CN101044410B - Partial discharge detection device and detection method for rotating electric machine - Google Patents

Abstract

A partial discharge detection device of a rotating electrical machine includes a metal frame (5) connected to a stator frame (7) of the rotating electrical machine; a power supply line (4) connected to one of a stator winding (6) corresponding to one of three phases in the metal frame and a neutral point wire connected to a neutral point of the three-phase stator winding and provided in the metal frame (5), for propagating a partial discharge signal generated by degradation of the stator winding (6); a sensor comprising a rod antenna (2) mounted around a power supply line or neutral lead (4) in a metal frame (5) for electrostatically and magnetically inducing a partial discharge signal propagating to the power supply line or neutral lead (4); and a detector (3) that receives the signal generated in the sensor via the signal lead (2) and detects the partial discharge by signal processing.

Description

Partial discharge detection device and detection method of rotating electric machine

technical field

The invention relates to a partial discharge detection device and a detection method of a rotating electrical machine.

Background technique

When a high-voltage rotating electrical machine operates continuously for a long time, the electrical insulation performance inside the electrical machine is continuously degraded due to electrical, thermal, mechanical and environmental stresses. This will eventually lead to dielectric breakdown and failure of the motor.

From a reliability and operational management perspective, high voltage rotating electrical machines need to monitor and diagnose internal insulation degradation. In particular, the stator windings of rotating electric machines are subjected to high electrical, thermal and mechanical stresses, therefore, it is very important to monitor and diagnose the insulation degradation of the stator windings.

In order to detect insulation degradation in the stator winding, a method of detecting a pulse-like signal caused by a partial discharge generated by insulation degradation of the stator winding is used. However, it is difficult to directly detect partial discharges occurring in coils inside rotating electric machines.

Generally, as disclosed in, for example, Japanese Laid-Open Patent Application Laid-Open No. Hei 4-299048, a detection sensor is installed in the stator winding, or installed in an end space inside a rotating electric machine, in order to detect a partial discharge in the Electromagnetic waves propagating in a rotating electrical machine or electrical pulse signals flowing through coils, coil connecting wires, and power lines.

In this method, since the distance between the position where the partial discharge occurs and the sensor is very short, the detection sensitivity is high and the detection noise will be small. However, the installation of the sensor has to be done after removing the coil, so it is time consuming. In addition, it is difficult to install the sensor.

Diagnosis of insulation degradation is especially necessary for existing rotating electrical machines that have been operating for decades. For this reason, there is a need for a partial discharge detection sensor that can be easily additionally mounted to such an existing rotating electric machine.

For example, Japanese Laid-Open Patent Publication No. Hei 4-299050 discloses a method of detecting a partial discharge signal by connecting a direct detection sensor such as an electrostatic capacitor or an inverter to a high-voltage charging unit such as a rotating electrical machine Stator windings in or connected to power lines of rotating electrical machines.

This detection method can ensure high detection sensitivity. However, since high electrical stress is applied to the direct detection sensor, the sensor itself needs to have high insulation performance.

Contents of the invention

As mentioned above, in the conventional partial discharge detection method, labor and time are required to install the detection sensor, and the sensor itself needs to have high insulation performance.

An object of the present invention is to provide a partial discharge detection method and device which can be easily mounted to a high-voltage component in a non-contact state and ensure high detection sensitivity and detection accuracy.

The partial discharge detecting device of a rotating electric machine according to the present invention includes: a metal frame connected to a stator frame of a rotating electric machine; Partial discharge signals from the degradation of stator windings; sensors consisting of rod or loop antennas mounted around a supply line or neutral lead in a metal frame so as to propagate electrostatically or magnetically inductively into the supply line or neutral a partial discharge signal of the neutral point lead; and a detector which receives a signal generated in the sensor via the signal lead and detects the partial discharge through signal processing.

The partial discharge detection method for a rotating electrical machine according to the present invention includes: in a metal frame connected to a stator frame of a rotating electrical machine, arranging a power line or neutral wire connected to a stator winding corresponding to each of three phases in the metal frame neutral lead; install two in-phase transducers, each of which includes a rod antenna, loop antenna, or multiple rod antennas each having one end electrically connected, and for each phase of the neutral lead or power line, at least separating two sensors at two points by a predetermined distance; and comparing the arrival time difference (arrival time lag), to detect the partial discharge signal generated by the degradation of the stator winding.

A partial discharge detection device for a rotating electric machine according to the present invention comprises: a conductive element electrostatically coupled to a power line or a neutral point lead connected to a stator winding of a rotating electric machine and not in contact with the power line or a neutral point lead; an impedance transformer having an input terminal of the terminal of the conductive element and having an input impedance greater than the output impedance; and a signal processing device for processing a detection signal obtained from an output terminal of the impedance transformer to detect a partial discharge pulse signal.

The partial discharge detection method of a rotating electric machine according to the present invention comprises: electrically connecting the output end of a conductive element to the input end of an impedance transformer, wherein the conductive element is connected to a power line or a neutral point lead of a stator winding of a rotating electric machine The electrostatic coupling is not greater than 10pF and is not in contact with the power line or the neutral point lead, the impedance transformer has an input impedance of not less than 500Ω and an output impedance of 50Ω to 75Ω; and by processing the detection obtained from the output of the transmission circuit The signal is used to detect the partial discharge signal, wherein the transmission circuit has a characteristic impedance of 50Ω to 75Ω and is connected to the output terminal of the impedance converter to match the impedance.

Description of drawings

FIG. 1A is a diagram showing a partial discharge detecting device for a rotating electrical machine using a power line connected to a stator winding according to a first embodiment of the present invention;

1B is a diagram showing a partial discharge detecting device for a rotating electric machine according to a first embodiment of the present invention, the device using a neutral point lead connected to a neutral point of a stator winding;

2 is a diagram showing a rod antenna and its supporting structure used as a sensor according to the first embodiment;

FIG. 3 is a block diagram showing a configuration example of a detector according to the first embodiment;

Fig. 4 is a graph showing output voltage waveforms in order to explain detector function;

5 is a waveform diagram showing an example of a partial discharge pulse propagating to a conductor and a waveform detected by a rod antenna in the first embodiment displayed on a waveform observer;

6 is a diagram showing a loop antenna and its supporting structure used as a sensor according to the first embodiment;

7A is an axial sectional view showing a partial discharge detection device for a rotating electric machine according to a second embodiment of the present invention;

7B is a radial cross-sectional view of the partial discharge detection device of the second embodiment;

Fig. 8 is a waveform diagram showing the relationship between the number of rod antennas and the antenna output voltage in the second embodiment;

9 is a diagram showing an example in which a plurality of rod antennas connected in series on one side are arranged on one line or on one circular arc as sensors according to the second embodiment;

10A is an axial sectional view showing a partial discharge detection device for a rotating electric machine according to a third embodiment of the present invention;

Figure 10B is a radial cross-sectional view of the device according to the third embodiment;

11A is an axial sectional view showing a connection arrangement for receiving a high-frequency current flowing through a resistor connected between an electrode and a metal frame to a detector in a third embodiment;

FIG. 11B is a radial cross-sectional view showing the connection arrangement for receiving a high-frequency current flowing through a resistor at the detector;

12 is a waveform diagram showing an example of a partial discharge pulse propagating to a conductor and a waveform detected by a resistor connected to an electrode in a third embodiment displayed by a waveform viewer;

13A is an axial sectional view showing a connection arrangement for receiving a high-frequency current at a detector at a detector in a third embodiment, wherein the current transformer is inserted in the connection electrode and the metal frame. in the conductor;

Figure 13B is a radial cross-sectional view showing the connection arrangement for receiving high frequency current from a current transformer at the detector;

14A is an axial sectional view showing an arrangement in the third embodiment in which arc-shaped divided electrodes are arranged concentrically around the power supply line;

14B is a radial cross-sectional view showing the arrangement, in which arc-shaped divided electrodes are concentrically arranged around the power supply line;

15A is an axial sectional view showing a partial discharge detection device for a rotating electrical machine according to a fourth embodiment of the present invention;

Fig. 15B is a radial sectional view of the fourth embodiment;

16A is an axial sectional view showing a connection arrangement for receiving a high-frequency current from a high-frequency transformer inserted at a connection electrode at a detector in a fourth embodiment. and metal frame conductors;

Fig. 16B is a radial cross-sectional view showing the connection arrangement for receiving high-frequency current from a high-frequency transformer at the detector;

17 is a diagram showing a partial discharge detection device for a rotating electrical machine according to a fifth embodiment of the present invention;

18 is a waveform diagram showing pulse waveforms obtained by connecting detection leads having the same length to two sensors and observing outputs using a synchronized waveform observation device in the fifth embodiment;

19 is a waveform diagram showing a pulse waveform obtained by observing an output with a synchronous waveform observation device upon detection when the pulse propagates in a direction entering into the rotating electrical machine from the opposite side;

FIG. 20 is a view showing a partial discharge detection device for a rotating electric machine according to a sixth embodiment of the present invention;

FIG. 21 is a waveform diagram showing waveforms obtained when a signal propagates in a direction entering the rotary electric machine in the sixth embodiment;

Fig. 22 is a waveform diagram showing a waveform obtained when a signal propagates from the rotating electric machine to the outside;

23A is a longitudinal sectional view showing the structure of a microstrip antenna used as a sensor according to a seventh embodiment of the present invention;

Figure 23B is a cross-sectional view of the microstrip antenna;

Fig. 24 is the equivalent circuit diagram of microstrip antenna;

FIG. 25 is a diagram showing the directivity of currents I ₀ and I ₁ generated in the microstrip antenna by electromagnetic waves propagating in space in this embodiment;

26 is a diagram showing a state in which a microstrip antenna of a seventh embodiment is connected to the inner surface of a metal frame;

27 is a waveform diagram showing a waveform obtained by detecting partial discharge generated at a stator winding using a microstrip antenna installed between a high-voltage conductor and a metal frame in a seventh embodiment;

28 is a diagram showing a partial discharge detection device for a rotating electric machine according to an eighth embodiment of the present invention;

29 is an equivalent circuit diagram showing a partial discharge detection device according to the eighth embodiment, viewed from a power supply line or a neutral point lead;

30 is a diagram showing a partial discharge detection device in which a transmission line having a characteristic impedance is directly connected to a conductive element without using an impedance transformer;

FIG. 31 is an equivalent circuit diagram showing a circuit formed by connecting an electrostatic capacitance and an impedance in series in FIG. 30;

FIG. 32 is a waveform diagram showing a comparison of frequency characteristics of detection gain between the arrangement of the eighth embodiment and the arrangement shown in FIG. 30;

Fig. 33 is an equivalent circuit diagram viewed from the signal processor in the eighth embodiment;

34A is a waveform diagram showing a voltage waveform obtained from one end of a transmission line when a resistive terminator equivalent to a transmission line is connected to both ends of the transmission line;

34B is a waveform diagram showing the voltage waveform obtained from one end of the transmission line when the resistive terminator is removed from both ends of the transmission line to open it;

FIG. 35A is a waveform diagram showing an example of a waveform when a partial discharge pulse is observed by using the detection method performed by the apparatus shown in FIG. 28;

35B is a waveform diagram showing an example of a waveform when a partial discharge pulse is observed by using the detection method performed by the apparatus shown in FIG. 30;

36 is a diagram showing a partial discharge detection device for a rotating electrical machine according to a ninth embodiment of the present invention;

37 is a diagram showing detection functions of two impedance converters according to a ninth embodiment of the present invention;

38 is a diagram showing inverter noise considered to be a main cause of noise at the time of partial discharge detection and a generation frequency band of a partial discharge waveform in a rotating electric machine;

39 is a waveform diagram showing signal waveforms appearing on the power supply line and the output terminals of the transmission paths of the two impedance converters in the ninth embodiment;

Fig. 40 is a diagram showing a partial discharge detecting device for a rotating electric machine according to a tenth embodiment of the present invention;

Fig. 41 is a diagram showing the process and time required for installing the partial discharge detection device according to the tenth embodiment of the present invention;

Fig. 42 is a diagram showing a partial discharge detection device for a rotating electric machine according to an eleventh embodiment of the present invention;

Fig. 43 is a diagram showing a partial discharge detecting device for a rotating electric machine according to a twelfth embodiment of the present invention;

Fig. 44 is a function explanatory diagram for distinguishing the propagation direction of pulses delivered to the signal processor in the twelfth embodiment;

45A is a waveform diagram showing voltage waveforms of partial discharge signals from two sensors caused by partial discharge pulses flowing from the stator winding of the electric rotating machine to the outside in the twelfth embodiment;

45B is a waveform diagram showing voltage waveforms of pulses from two sensors caused by noise pulses flowing from the outside to the stator windings of a rotating electric machine;

Fig. 46 is a diagram showing a partial discharge detecting device for a rotating electric machine according to a thirteenth embodiment of the present invention;

FIG. 47 is an equivalent circuit diagram showing a partial discharge detection device according to a thirteenth embodiment of the present invention viewed from a power line or a neutral point lead; and

FIG. 48 is a graph showing a comparison of frequency characteristics of detection gain between the thirteenth embodiment of the present invention and the setup shown in FIG. 30 .

Detailed ways

FIG. 1A is a diagram showing a partial discharge detection device for a rotating electrical machine using a power supply line connected to a stator winding according to a first embodiment of the present invention. FIG. 1B is a diagram showing a partial discharge detection device for a rotating electric machine using a neutral point lead connected to a neutral point of a stator winding.

1A and 1B, the stator winding 6 corresponding to one of the three phases of the rotating electric machine (one phase is shown in FIGS. 1A and 1B ) is held in a slot formed in the stator core (not shown), The stator core is mounted to the inner surface of the stator frame 7 .

Install the cylindrical metal frame 5 to the stator frame 7 . In FIG. 1A , insulating supports (not shown) support the supply wires 4 connected to the stator windings 6 . The power cord 4 is set on the central axis of the metal frame 5 . In Figure IB, an insulating support (not shown) supports the neutral point lead 4 connected to the neutral point 6a of the three-phase stator winding. The neutral point lead wire 4 is arranged on the central axis of the metal frame 5 . A rod antenna 1 made of a conductive material and used as a sensor is mounted in a non-contact state with respect to a power line or a neutral point lead 4 .

In this case, the rod antenna 1 is arranged parallel to the power line or the neutral point lead 4, and is fixed to the antenna support insulating member 8, which is mounted to two appropriate ends of the metal frame 5. Click on it, as shown in Figure 2.

A signal lead 2 is connected to one end of the rod antenna 1 . The partial discharge pulse input through the signal lead 2 is received by the detector 3 through a resistor or a high frequency transformer (not shown). A preamplifier for signal amplification amplifies the partial discharge pulse input to the detector 3, if necessary.

As shown in Figure 3, the detector 3 includes an analog signal processing circuit 54 with a comparison circuit 51, a gate circuit 52, and an operation circuit 53, and the operation circuit 53 includes an integrating circuit and a peak detection circuit; A display device 55 for the peak output of the analog signal processing circuit 54; an analog-to-digital conversion circuit 56 for converting the integrated value output from the analog signal processing circuit 54 into digital data;

In the partial discharge pulse detection device with the above arrangement, when a partial discharge occurs due to insulation degradation of the stator winding 6, a partial discharge signal is propagated to the power line or the neutral point lead 4.

The partial discharge signal is electrostatically or electromagnetically induced to the rod antenna 1 from the power line or the neutral point lead 4, and is input to the detector 3 from the signal lead 2 through a resistor or a high frequency converter.

In the detector 3 , a comparison circuit 51 compares a predetermined threshold 62 with a signal waveform value 61 , as shown in FIG. 4 . Gate 52 ignores signals equal to or less than the threshold. Gate 52 receives a signal greater than the threshold for a predetermined period of time 63 . The peak detection circuit 53 detects, for example, a peak 64 appearing for the first time within the period, or an amplitude (integral value) 65 of partial discharge. The detected value is displayed on a waveform observation device such as an oscilloscope or a display device 55 of a recorder. The analog-to-digital conversion circuit 56 simultaneously converts the peak value into a digital value, and stores the digital value in the storage device 57 .

FIG. 5 shows examples of waveforms displayed on the waveform observation device obtained by causing the detector 3 and the rod antenna 1 to detect a partial discharge pulse propagating to the power line or neutral point lead 4 . As shown in Figure 5, a pulsed signal 31 propagating to the power line or neutral lead 4 results in a pulsed waveform 32 in the antenna having a first wave of the same polarity as the first wave of the propagating pulse in the wire.

By observing the pulse waveform with the same polarity as the first wave displayed on the waveform observation device, it can be known that the partial discharge pulse occurs in the stator winding.

A rod antenna 1 serving as a sensor is installed in a metal frame 5 in a non-contact state corresponding to a power line or a neutral point lead 4 connected to a stator winding 6 . The detector 3 can receive and detect the partial discharge signal generated due to the degradation of the stator winding and induced electrostatically or electromagnetically to the whip antenna 1 from the power line or the neutral point lead 4 . There is no need to change the internals of the rotating motor. The non-contact sensor can be mounted relatively easily to the high voltage part only by changing the metal frame around the power line or neutral point lead 4 of the rotating electric machine.

In the above-described embodiments, if the power line or neutral point lead 4 provided in the metal frame 5 is the power line connected to the stator winding 6, a high voltage is applied near the antenna. Therefore, it is necessary to alleviate electric field concentration by covering the antenna with an insulating material such as epoxy resin or processing the end of the antenna.

In the above-described embodiments, the rod antenna 1 is used as a sensor. The loop antenna 9 shown in FIG. 6 can also detect electrostatically or electromagnetically induced partial discharge signals from the power line or neutral point lead 4 .

In the above-described embodiments, the rod antenna 1 or the loop antenna 9 is installed parallel to the power line or the neutral point lead 4 . The antenna can be arranged perpendicular to the mains or neutral lead 4 .

7A is an axial sectional view showing a partial discharge detection device for a rotating electrical machine according to a second embodiment of the present invention. Fig. 7B is a radial sectional view. The same reference numerals as in Figs. 1A, 1B and 2 denote the same components in Figs. 7A and 7B.

In the second embodiment, as shown in FIGS. 7A and 7B, a plurality of rod antennas 1 serving as sensors are provided on the inner surface of a metal frame 5, which surround a power line or a neutral point lead 4 and have the same angle interval. The antenna support insulating member 8 fixed to the metal frame 5 supports the rod antenna 1 . A connecting conductor 10 usually connects one end of each rod antenna 1 . The connecting conductor 10 is connected to the detector 3 via the signal lead 2 .

FIG. 8 shows the relationship between the number of rod antennas and detection sensitivity=(the first peak value of the detection waveform of the sensor)/(the first peak value of the waveform propagated through the power line or the neutral point lead).

When the number of rod antennas is 1, the detection sensitivity is defined as 1.

It is obvious from the graph shown in FIG. 8 that the greater the number of rod antennas, the higher the output of the sensor. The detection sensitivity of the sensor is higher in an arrangement comprising a plurality of rod antennas than in an arrangement with one rod antenna.

With this arrangement, it is not necessary to change the inside of the rotary electric machine, which is the same as the first embodiment. Non-contact sensors can be mounted to high voltage components relatively easily simply by changing the metal frame around the power wire or neutral lead of a rotating electrical machine. In addition, detection sensitivity can be improved.

In the second embodiment, a plurality of rod antennas 1 are arranged in a circular shape. Alternatively, as shown in FIG. 9, a plurality of rod antennas 1 are arranged concentrically with respect to the power line or neutral point lead wire 4 (the lower half of FIG. 9) or are arranged linearly (the upper half of FIG. 9). half). Alternatively, as shown in FIG. 9 , the upper half of the rod antenna is arranged in a straight line, and the lower half of the rod antenna is arranged in an arc shape, and vice versa. These settings can even produce the same functions and effects as above.

10A is an axial sectional view showing a partial discharge detection device for a rotating electrical machine according to a third embodiment of the present invention. Fig. 10B is a radial sectional view thereof. The same reference numerals as in FIGS. 1A and 1B denote the same components in FIGS. 10A and 10B .

Referring to FIGS. 10A and 10B, the stator winding 6 corresponding to one of the three phases of the rotating electrical machine (one phase is shown in FIGS. 10A and 10B ) is stored in a slot formed in the stator core (not shown), and The stator core is installed on the inner surface of the stator frame 7.

Install the cylindrical metal frame 5 to the stator frame 7 . An insulating support (not shown) supports the supply or neutral lead 4 connected to the stator winding 6 . The power line or neutral point lead 4 is set on the central axis in the metal frame 5 . A cylindrical electrode 11 electrostatically coupled to the mains or neutral lead 4 is arranged concentrically around the mains or neutral lead 4 . In this case, the electrode 11 is fixed to an electrode supporting insulating member 12 which is fitted to an appropriate point on the inner surface of the metal frame 5 .

A resistor 13 is connected between the electrode 11 and the metal frame 5, as shown in FIGS. 11A and 11B. The signal lead 2 is connected to one end of the resistor 13 on the electrode side. A high-frequency current generated based on a partial discharge pulse flowing through the signal wire 2 is received by the detector 3 through a resistor or a current transformer (not shown). A preamplifier for signal amplification amplifies the partial discharge pulse input to the detector 3, if necessary.

The arrangement of the detector 3 is the same as that shown in FIG. 3 described in the first embodiment, and thus description thereof will be omitted.

In the partial discharge pulse detection device with the above arrangement, when a partial discharge occurs due to insulation degradation of the stator winding 6 , the partial discharge signal propagates to the power line or the neutral point lead 4 .

When the partial discharge signal propagates to the power line or the neutral point lead 4, the partial discharge signal of a high-frequency current greater than several KHz flows through the resistor 13 connected between the metal frame 5 and the electrode 11, which is electrostatically coupled to the power line or neutral lead 4. A high-frequency current is input to the detector 3 from the signal lead 2 through a resistor or a current transformer (not shown).

The detector 3 can detect a signal in the optimum high frequency band by the same signal processing as that described in the first embodiment.

Fig. 12 shows a partial discharge pulse 33 propagating to a power line or neutral point lead 4, and a waveform 34 detected by a resistor 13 connected to an electrode 11, arranged concentrically with respect to the power line or neutral point lead 4. The electrode 11.

It is evident from Figure 12 that a partial discharge pulse 33 propagating to the supply line or neutral lead 4 results in a pulse waveform 34 in the detection circuit comprising the electrode 11 and resistor 13, which has a polarity consistent with that in the conductor The first wave of the same polarity as the first wave of the propagating pulse.

By observing the pulse waveform with the same polarity as the first wave displayed on the waveform observation device, it can be known that the partial discharge pulse occurs in the stator winding.

Concentrically arranged around the circumference of the supply line or neutral point lead 4 is a cylindrical electrode 11 electrostatically coupled to the supply line or neutral point lead 4 arranged in the metal frame 5 and connected to the stator winding 6 . The detector 3 receives and processes a high frequency current flowing through a resistor 13 connected between the electrode 11 and the metal frame 5 (ground). Therefore, the detector 3 can detect the partial discharge signal due to the degradation of the stator winding. There is no need to change the internals of the rotating motor. Non-contact sensors can be mounted to high voltage components relatively easily simply by changing the metal frame around the power wire or neutral lead of a rotating electrical machine.

In the above-described embodiment, the detector 3 receives a high-frequency current flowing through the resistor 13 connected between the electrode 11 and the metal frame 5 (ground). Alternatively, as shown in FIGS. 13A and 13B , a high-frequency current transformer 14 may be inserted in the connecting conductor connecting the electrode 11 and the metal frame 5 (ground). The detector 3 can receive the high frequency current detected by the high frequency converter 14 .

In the above-described embodiments, the cylindrical electrode 11 electrostatically coupled to the power line or neutral lead 4 is arranged concentrically around the power line or neutral lead 4 . As shown in FIGS. 14A and 14B , it is also possible to divide the cylindrical electrode 11 in the axial direction into a plurality of divided electrodes 15 each having a ring shape, and to arrange the divided electrodes 15 concentrically around the power line or neutral point lead 4 . In this case, a plurality of divided electrodes 15 may be provided in the longitudinal direction of the power line or neutral point lead 4 .

This arrangement makes it possible to adjust the electrostatic capacitance between the high-frequency transformer 14 and the divided electrodes 15 so that a signal in an optimum high-frequency band can be detected.

In the above-described embodiments, electrical stress is applied to the electrode surface. Therefore, electric field concentration can be moderated by covering the surface of the electrode with an insulating material such as epoxy resin or appropriately treating the end of the electrode.

15A is an axial sectional view showing a partial discharge detection device for a rotating electric machine according to a fourth embodiment of the present invention. Fig. 15B is a radial sectional view. The same reference numerals as in FIGS. 11A and 11B denote the same components in FIGS. 15A and 15B .

In the fourth embodiment, as shown in FIGS. 15A and 15B , the metal frame 5 is radially cut and separated at an intermediate point. A cylindrical electrode 16 having the same diameter as the metal frame is inserted at the point of separation and arranged concentrically around the power line or neutral point lead 4 . Both open ends of the cylindrical electrode 16 are mounted to the open ends of the separated metal frame 5 via the ring-shaped electrode supporting insulating member 17 . End portions of the connection conductors 18 disposed across the electrodes 16 are respectively connected to the separate metal frames 5 .

Resistor 13 is connected between electrode 16 and metal frame 15 . The signal lead 2 is connected between one end of the resistor 13 on the electrode side and a detector 3 provided to receive a high-frequency current flowing through the resistor 13 .

This arrangement even allows detection of partial discharge based on the same function as the third embodiment. Therefore, there is no need to change the internal structure of the rotating electrical machine. Non-contact sensors can be mounted to high voltage components relatively easily simply by changing the metal frame around the power wire or neutral lead of a rotating electrical machine.

In the fourth embodiment, the detector 3 receives a high frequency current flowing through a resistor 13 connected between an electrode 16 and the metal frame 5 (ground). Alternatively, as shown in Figures 16A and 16B, the high frequency current transformer 14 may be coupled to a conductor connected between the electrode 16 and the metal frame 5 (ground). The detector 3 can receive the high frequency current detected by the high frequency converter 14 .

Fig. 17 is a diagram showing a partial discharge detection device for a rotating electric machine according to a fifth embodiment of the present invention. The same reference numerals as in FIGS. 1A and 1B denote the same components in FIG. 17 .

Referring to FIG. 17, the stator winding 6 corresponding to one of the three phases of the electric rotating machine (one phase is shown in FIG. 17) is held in a slot formed in the stator core (not shown), and the stator The iron core is mounted to the inner surface of the stator frame 7 .

Install the cylindrical metal frame 5 to the stator frame 7 . Insulating supports (not shown) support the supply wires 4 connected to the stator windings 6 . The power cord 4 is set on the central axis in the metal frame 5 . Alternatively, an insulating support (not shown) supports the neutral point lead 4 connected to the neutral point of the three-phase stator winding 6 . The neutral point lead 4 is set on the central axis in the metal frame 5 .

For each phase of the power line or neutral point lead 4, sensors 21 and 22 each including a rod antenna are installed corresponding to the power line or neutral point lead 4 at two points A and B separated by a predetermined distance. The waveform comparator 23 receives the outputs from the sensors 21 and 22 and compares the waveforms. The results can be observed by using a waveform observation device.

FIG. 18 shows waveforms obtained by connecting the sensors 21 and 22 to the waveform comparator 23 via detection leads of the same length, and by observing the output with the simultaneous waveform observation device in the partial discharge detection device having the above arrangement. Fig. 19 shows a pulse waveform obtained by detecting a pulse propagating in a direction entering the rotating electrical machine from the opposite side thereof. 18 and 19, the abscissa represents time, and the ordinate represents waveform output (amplitude).

When the pulse propagates from the rotating electrical machine to the power line or neutral point lead 4, the output waveform 35 from the sensor 21 is first observed, and then after a delay of several nanoseconds, the output waveform 36 from the sensor 22 is observed, as shown in Fig. 18 shown. When the pulse propagates from the power system to the power line or neutral point lead 4, the output waveform 39 from the sensor 22 is first observed, and then after a delay of several nanoseconds, the output waveform 38 from the sensor 21 is observed, as shown in Figure 19 shown.

The delay times 37 and 40 of a few nanoseconds correspond to the pulse propagation times between the sensors 21 and 22 . Therefore, the direction of pulse propagation can be estimated by detecting the difference in arrival time of the waveform 37 or 40 between the sensors 21 and 22 .

It is necessary to separate the sensors 21 and 22 by such a distance that the waveform time difference between them can be recognized.

For example, the time width of about 1/4 of the time width of the first half-wave of the first leading edge pulse signal (for example, 35 ) allows the waveform observation device to easily identify the arrival time difference. Therefore, when the frequency of the pulse signal is 10 MHz, the necessary distance between the sensor installation points A and B is about 4 m.

The lower the frequency of the signal, the longer the pulse waveform oscillation period. In order to accurately detect the arrival time differences 37 and 40 of the pulse waveforms, the distance between the sensors 21 and 22 must be long.

Typically, signals including partial discharge signals are propagated from rotating electrical machines, while noise is mainly propagated from the side of the power system opposite to the generator side. Therefore, noise can be separated from the power system by measuring the difference in arrival time of the waveform between the sensors 21 and 22 .

Since the sensor 21 is close to the stator winding 6 serving as a source of partial discharge, the above arrangement can improve partial discharge detection sensitivity.

Even when the signal leads connected to the sensors 21 and 22 have different lengths, correction can be made at the time of pulse detection if the lengths are known. Therefore, noise can be separated from the power system as described above.

In this embodiment, for each phase of the supply or neutral lead 4, sensors 21 and 22 are mounted at two points separated by a predetermined distance in a metal frame 5 which holds the Power line or neutral point lead 4. Partial discharge can be detected by measuring the arrival time difference between output signal waveforms from two sensors installed in the same phase. No need to change the internals of the rotating motor. Non-contact sensors can be mounted to high voltage components relatively easily simply by changing the metal frame around the power wire or neutral lead of a rotating electrical machine. In addition, noise pulses from the power system can be separated from pulses from the rotating electrical machine. Therefore, partial discharge can be accurately detected.

In the fifth embodiment, two sensors 21 and 22 each including a rod antenna are installed. Two sensors each comprising a loop antenna or a plurality of rod antennas electrically connected at one end may be installed.

20 is a diagram showing a partial discharge detection device for a rotating electric machine according to a sixth embodiment of the present invention. The same reference numerals as in FIGS. 1A and 1B denote the same components in FIG. 20 .

Referring to FIG. 20, the stator winding 6 corresponding to one of the three phases of the electric rotating machine (one phase is shown in FIG. 20) is held in a slot formed in a stator core (not shown), and the stator The iron core is mounted to the inner surface of the stator frame 7 .

Install the cylindrical metal frame 5 to the stator frame 7 . An insulating support (not shown) supports a conductor 4a, such as a phase-separated bus bar, a coil connection conductor, or a neutral lead to which the partial discharge pulse signal propagates. The conductor 4 a is set on the central axis in the metal frame 5 .

Two loop antennas 24 and 25 are arranged at points A and B separated by a predetermined distance in the same direction along the conductor 4a. The terminals Aa and Ab and the terminals Ba and Bb connected to the signal leads of the loop antennas 24 and 25 are arranged in opposite directions so that the first peaks of the output waveforms from the signal leads of the loop antennas have opposite polarities.

In addition, the length of the signal lead wire connected to the loop antenna 25 away from the rotating electric machine is set long so that when the pulse flows through the conductor 4a in the direction entering the rotating electric machine, the output waveform generated between the terminals Aa and Ab is the same as that at the terminal Aa and Ab. The output waveforms generated between terminals Ba and Bb have the same timing. That is to say, the signal lead wire of the loop antenna 25 is made longer, so that the signal propagation time of the signal lead wire of the loop antenna 25 becomes longer than the signal propagation time of the signal lead wire of the loop antenna 24, and the longer time is the length of the loop antenna 24 and the loop antenna 24. 25 the signal propagation time difference between.

Connect the signal leads to extract pulse voltages with opposite polarities corresponding to a single propagating pulse. The signal processor 26 receives a voltage signal obtained from the common connection points X and Y as the sum of pulse waveforms of opposite polarity. The results can be observed by using a waveform observation device.

FIG. 21 shows an example of output waveforms from terminals Aa-Ab and Bb-Ba and the sum of both waveforms when a signal propagates in the direction entering the rotating electrical machine in the partial discharge detection apparatus having the above arrangement.

Referring to FIG. 21 , reference numeral 41 denotes a voltage waveform observed across terminals Aa-Ab, 42 denotes a voltage waveform observed across terminals Ba-Bb, and 43 denotes a sum waveform of voltage waveforms 41 and 42 .

FIG. 22 shows an example of output waveforms observed at the terminals Aa-Ab and Ba-Bb and the sum of these two waveforms when the signal propagates from the rotating electrical machine to the outside.

Referring to FIG. 22 , reference numeral 44 denotes a voltage waveform observed at terminals Aa-Ab; 45 denotes a waveform observed at terminals Ba-Bb; and 46 denotes a sum waveform of voltage waveforms 44 and 45 .

As shown in FIG. 22, the waveform sum of the loop antennas 24 and 25 maintains the peak value of the first half wave of the pulse waveform propagating from the rotating electric machine. However, the peak value of the first half wave of the pulse waveform propagating in the direction entering the rotating electrical machine is cancelled.

In order to maintain the waveform shown in FIG. 22 and the first half wave of 46 when the pulse propagates from the rotating electric machine to the outside, the loop antennas 24 and 25 must have a distance corresponding to the time width of the first half wave of the waveform and 46 .

For example, when the frequency of the pulse signal (such as the waveform 41 in FIG. 21) is 10 MHz, the necessary distance between the loop antennas 24 and 25 is about 7 m. Typically, signals including partial discharge signals are propagated from rotating electrical machines, while noise is mainly propagated from the power system. Therefore, noise propagating from the system can be separated.

In the above-described embodiment, the terminals Aa and Ab and the terminals Ba and Bb connected to the signal leads of the loop antennas 24 and 25 arranged in the same direction are arranged in opposite directions so that the output waveforms from the signal leads of the loop antennas The first wave of peaks has the opposite polarity. Alternatively, loop antennas 24 and 25 may be arranged in opposite directions to induce voltages in opposite directions.

As described above, in this embodiment, the loop antennas 24 and 25 are separated by a predetermined distance and placed in the metal frame 5 holding the conductor 4a such as a phase-separated bus bar, a coil connection conductor, or a propagation part Discharge pulse signal to the neutral point lead of a rotating electrical machine. The signal lead from the antenna is arranged such that the peaks of the output pulse waveform obtained from the signal lead connected to the antenna have opposite polarities. The setting is adjusted so that the pulse output to the signal lead terminals of the antenna connected to the stator winding remote from the rotating electric machine arrives at the same time as the pulse output to the signal lead terminals of the antenna connected to the stator winding close to the rotating electric machine. The signal processor 26 receives the pulse signals induced in the two antennas, and detects the sum of the pulse waveforms. There is no need to change the internal settings of the rotating motor. It is relatively easy to mount the non-contact sensor to the high voltage part only by changing the metal frame around the conductor 4a. In addition, detection sensitivity can be improved.

In the sixth embodiment, two loop antennas 24 and 25 are installed. Two sets of multiple loop antennas connected in series can be installed. This setup can even produce the same functions and effects as above.

23A is a longitudinal sectional view showing the structure of a microstrip antenna used as a sensor for a partial discharge detection device for a rotating electric machine according to a seventh embodiment of the present invention. Fig. 23B is a cross-sectional view.

Referring to Figs. 23A and 23B, the coaxial cable 61 has a characteristic impedance of 50Ω. The coaxial cable 61 includes a planar portion and a 50Ω resistive terminator 62 . The plate portion has a three-layer structure including an insulating material 64 and a transmission line 65 formed on a plate electrode 63 . An insulating layer 66 covers the structure.

According to the geometric setting, the characteristic impedance between the transmission line 65 and the plate electrode 63 is 50Ω, which is equal to the characteristic impedance of the terminator 62 .

The coaxial cable used as the signal lead has a characteristic impedance of 50Ω. The transmission line 65 of the plate is connected to the center line of the coaxial cable 60 . The plate electrode 63 is connected to the shielded wire of the coaxial cable.

A coaxial cable used as a signal lead prevents noise from mixing with surrounding components other than the antenna.

Fig. 24 shows an equivalent circuit of the microstrip antenna shown in Figs. 23A and 23B.

Referring to FIG. 24, reference numeral 67 denotes a characteristic impedance of a coaxial cable; 68, an electric field component of an electromagnetic wave; and 69, a magnetic field component of an electromagnetic wave. The angle formed by the transmission line 65 and the propagation direction 70 of the electromagnetic wave propagating through space is denoted by θ.

FIG. 25 shows the directivity of currents I ₀ and I ₁ generated in a microstrip antenna by electromagnetic waves propagating in space.

When the angle formed by the transmission line 65 with respect to the electromagnetic wave propagation direction is 0°, the sensitivity of the microstrip terminal current I ₀ generated in the coaxial cable 61 is maximized. In other words, the output of the coaxial cable is maximized with respect to electromagnetic waves propagating in the direction of the coaxial cable 61 .

In the stator frame of the rotating pole, or in the space inside the metal frame that holds the power line connected to the stator winding or the neutral point lead connected to the stator winding of the rotating electrical machine, once a partial discharge occurs on the stator winding, the electromagnetic wave be disseminated.

Therefore, by installing the microstrip antenna 60 (as shown in FIG. 26 ) having the above-mentioned structure on the inner surface of the metal frame 5 along the direction of the stator winding, it is possible to detect partial discharge signals with high sensitivity.

FIG. 27 is a waveform diagram showing waveforms obtained by installing the above-described microstrip antenna 60 between a high-voltage conductor and a metal frame and detecting partial discharge of a stator winding.

As is apparent from the waveforms shown in FIG. 27, since the partial discharge pulse signal 71 generates the pulse waveform 72 in the coaxial cable connected to the antenna, the partial discharge signal can be detected.

If the frame 7 or the metal frame 5 of the electric rotating machine has a portion where electromagnetic waves leak to the outside, partial discharge can be detected by installing a microstrip line on the outer surface of the frame near the portion.

As described above, in this embodiment, the microstrip antenna 60 is mounted on the inner or outer surface of the stator frame of the rotating electrical machine by connecting one end to the resistive terminator 62 and including the plate electrode 63, the insulating material 64 and the transmission line 65. Partial discharges can be detected on or mounted on the inner or outer surface of a metal frame holding the supply wires or neutral point leads connected to the stator windings of rotating electrical machines. It is not necessary to change the internals of the rotating electrical machine. Non-contact sensors can be mounted to high voltage components relatively easily simply by changing the metal frame around the power wire or neutral lead of a rotating electrical machine.

In the seventh embodiment, a plurality of microstrip antennas 60 can be installed in a metal frame or a stator frame of a rotating electric machine by utilizing the directivity of the antenna. When partial discharge occurs due to degradation of the stator winding, electromagnetic waves propagate through the space between the stator winding and the stator frame. By comparing the signal strengths output from antennas that detect electromagnetic waves, the source of partial discharge can be determined.

Fig. 28 is a diagram showing a partial discharge detection device for a rotating electric machine according to an eighth embodiment of the present invention.

Referring to FIG. 28, the stator winding or winding 101 corresponding to one of the three phases of the rotating electric machine (one phase is shown in FIG. 28) is held in a slot formed in the stator core (not shown), and the The stator core is mounted to the inner surface of the stator frame 100. Power lines 102 are connected to the stator windings 101 of each phase. Alternatively, the neutral lead 102 may be connected to the neutral of the three-phase stator windings. A support member (not shown) supports a non-contact conductive element 103 made of copper or aluminum and electrostatically coupled to the power or neutral lead 102 .

An input 106 of an impedance transformer 105 in which at least the input impedance Zin is greater than the output impedance Zout is electrically connected to the conductive element 103 via a lead 104 . The partial discharge pulse signal is detected by inputting the detection signal from the output terminal 109 of the transmission line 108 (characteristic impedance Z ₀ ) to the signal processor 110 . The output terminal 109 is connected to the output terminal 107 of the impedance transformer 105 so as to match impedance.

A coaxial cable having a characteristic impedance of 50Ω or 75Ω is usually used as the transmission line 108 . Therefore, Zout is usually 50Ω or 75Ω.

Next, the function of the partial discharge detecting device of the rotating electrical machine having the above arrangement will be described.

FIG. 29 shows an equivalent circuit viewed from the power line or neutral point lead 102 in FIG. 28 . The power line or neutral point lead 102 is connected in series to the input impedance Zi and the electrostatic capacitance C of the impedance converter 105 , and is grounded to the ground point 111 . The ratio between the output _Vo at the output 107 of the impedance transformer 105 and the peak value Vi of the AC voltage flowing to the supply line or neutral lead 102 is given by:

$\mathrm{<span\; class="notranslate">\; Vo</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; Vi</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; /</span>\sqrt{<span\; class="notranslate">\; \{</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>{<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; /</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&pi;fCZin</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ]</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; \}</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

Figure 30 shows an arrangement configured to connect a transmission line 108 having a characteristic impedance Z ₀ directly to the conductive element 103 without using an impedance converter.

FIG. 31 shows an equivalent circuit formed by connecting the electrostatic capacitance C and the characteristic impedance Z ₀ in series in FIG. 30 . The ratio of the output _Vo of the sense terminal 114 to the peak value Vi of the AC voltage flowing to the supply line or neutral lead 102 is given by:

$\mathrm{<span\; class="notranslate">\; Vo</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; Vi</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; /</span>\sqrt{<span\; class="notranslate">\; \{</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>{<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; /</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&pi;fCZ</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ]</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; \}</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$

A coaxial cable having a characteristic impedance of 50Ω or 75Ω is usually used as the transmission line 108 .

Fig. 32 shows the frequency characteristic 117 (20*Log(Vo/Vin)) in Figs. 28 and 29 and the frequency characteristic 116 in Figs. Impedance converter, and obtained by setting C=1pF, Zin=50kΩ, and Zout=50Ω, and the frequency characteristic 116 is obtained by setting C=1pF and Z0=50Ω without using an impedance converter .

Among them, the electrostatic capacitance and impedance form a high-pass filter.

As can be clearly seen from FIG. 32, in the detection method using the impedance transformer 105 connected to the conductive element 103 shown in FIG. The output gain is greater in the method.

FIG. 33 shows an equivalent circuit viewed from the signal processor 110 in FIG. 28 . A resistance value (Z ₀ ) 118 equal to characteristic impedance Z ₀ terminates both ends of transmission line 108 to prevent reflections of signals propagating in transmission line 108 from ends 107 and 109 .

34A and 34B are waveform diagrams showing the effect of preventing reflection at the terminal. 34A shows a voltage signal waveform 119 obtained from terminal 109 when a terminator (Z ₀ ) 118 equal to characteristic impedance Z ₀ terminates both ends 107 and 109 of transmission line 108 .

FIG. 34B shows the waveform 122 obtained from the terminal 109 when the terminator (Z ₀ ) 118 is removed from both ends of the transmission line 108 to open it. The waveform 122 is the sum of the waveform 120 obtained by directly inputting the waveform output from the terminal 107 to the terminal 109 and the voltage waveform 121 appearing on the terminal 109 after a time T during which the waveform is completely reflected by the terminal 109 by Transmission line 108 propagates, is reflected by terminal 107 , and propagates through transmission line 108 . Depending on the length of the transmission line 108 , the propagation time T is shortened and produces an output waveform that is substantially different from the original waveform 120 .

That is, when the output impedance Zout of the impedance transformer 105 shown in FIG. 28 , the characteristic impedance Z ₀ of the transmission line 108, and the input impedance of the signal processor 110 are set equal (Zout=Z ₀ ), the waveform are accurately transmitted to the signal processor 110.

FIG. 35A shows an example of a partial discharge pulse observed by using the detection method in FIG. 28 . Reference numeral 124 in FIG. 35A denotes a partial discharge signal 125 flowing to the power supply line, and 126 denotes a signal output to the transmission line terminal 108 . In FIG. 35A, the partial discharge pulse waveform 127 can be accurately detected. FIG. 35B shows an example of a partial discharge pulse observed by using the detection method in FIG. 30 . Reference numeral 128 in FIG. 35B denotes a partial discharge signal 129 flowing to a power supply line, and 130 denotes an output signal from a transmission line terminal whose pulse peak value is smaller than that of the partial discharge signal 129 .

In the embodiments described above, a conductive element electrostatically coupled to the supply or neutral lead 102 connected to the stator winding connection of the rotating electrical machine is provided in a non-contact state. Even by providing a capacitor connected to the power line or the neutral point lead 102 instead of the conductive element, partial discharge can be detected as described above.

In the partial discharge detecting device for a rotating electrical machine according to the eighth embodiment, one end of the conductive member 103 that is electrostatically coupled to the power supply line 102 or the neutral point lead 102 and is in a non-contact state with respect to it, or is connected to the power supply line or One end of the capacitor of the neutral point lead 102 is electrically connected to the input of an impedance converter whose input impedance is greater than the output impedance, wherein the power line 102 is connected to the stator winding corresponding to one of the three phases of the rotating electrical machine, the middle The neutral point lead 102 is connected to the neutral point of the three-phase stator winding. The partial discharge pulse signal is detected from an output terminal of the impedance converter or an output terminal of a transmission circuit connected to the output terminal of the impedance converter so as to match impedance. It is not necessary to change the internals of the rotating electrical machine. Non-contact sensors can be mounted to high voltage components relatively easily simply by changing the metal frame around the power wire or neutral lead of a rotating electrical machine. In addition, partial discharge can be detected with high detection sensitivity and accuracy.

36 is a diagram showing a partial discharge detection device for a rotating electric machine according to a ninth embodiment of the present invention.

Referring to Fig. 36, a power supply line 102 is connected to a stator winding 101 corresponding to one of three phases of the electric rotating machine. Alternatively, the neutral point lead 102 may be connected to the neutral point of the three-phase stator winding 101 . At least two conductive elements 103 and 138 are electrically connected via leads 104 and 140 to the input terminals 106 and 133 of two impedance converters 105 and 132 having different input impedance values and wherein at least the input impedance is greater than the output impedance, the at least two Each conductive element 103 and 138 has the same or different electrostatic coupling with the power line or neutral lead 102 and is not in contact with the power line or neutral lead 102 . The partial discharge pulse signal is detected by inputting the detection signal to the signal processor 137 from the output terminals 109 and 136 of the transmission lines 108 and 135 connected to the output terminals 107 and 134 of the impedance converters 105 and 132 for matching impedance.

As shown in Figure 37, the signal processor 137 has the function (S1) of determining the peak detection moment of the pulse signal output from the output terminal 107 of the impedance converter 105, wherein the impedance converter 105 has a smaller input impedance value, And has a function (S2) of determining the pulse signal output from the output terminal 134 of the impedance converter 132 having a larger input impedance value as a partial discharge signal (S2).

Fig. 38 is a graph showing inverter noise considered as a noise factor at the time of partial discharge detection and a generation frequency band of a partial discharge waveform in a rotating electric machine. Converter noise typically includes frequencies up to several MHz. However, partial discharge signals include frequencies of several MHz or higher.

The input impedance Zin and the electrostatic capacitance C of the impedance converter 105 form a high-pass filter that allows only high-frequency components of a signal to pass, as shown in FIG. 32 . The cutoff frequency of the high pass filter is given by

fc=1/2πZ _in C (3)

When the input impedance value of the impedance converter 105 is selected such that the cutoff frequency I exists in a frequency band of at least 10 MHz in which only partial discharge signal components exist, only partial discharge pulses are output from the output terminal 107 of the impedance converter 105 shown in FIG. 38 .

However, as shown in Fig. 38, partial discharge sometimes includes broadband components in one pulse. Therefore, it is impossible to reproduce an accurate discharge waveform flowing in the power supply line by the output of the impedance converter 105 . When a low cutoff frequency (cutoff frequency II) is set up to a frequency band where noise exists, as shown in FIG. 38 , an accurate partial discharge waveform can be detected.

39 shows a partial discharge signal 139 flowing to the power line, a waveform 141 appearing at the output 109 of the transmission line 108 of the impedance transformer 105, and a waveform 143 appearing at the output 136 of the transmission line of the impedance transformer 132, wherein The impedance of the impedance converter 105 is selected such that a cutoff frequency I exists in a frequency band in which only partial discharges are generated, and the impedance converter 132 has a cutoff frequency II existing in a low frequency band containing noise.

As is apparent from FIG. 39, the output terminal 107 of the impedance converter 105 outputs a partial discharge waveform 141 containing only high frequency components of the partial discharge. The output terminal 134 of the impedance converter 132 accurately outputs a partial discharge waveform 143 .

However, since the low frequency region is likely to contain converter noise, as shown in Figure 38, a noise detection error occurs.

The signal processor 137 receives the waveform detected by the impedance transformer 132 having a low cut-off frequency by using the generation of the partial discharge waveform detected by the impedance transformer 105 having a frequency band for detecting only the partial discharge as a trigger. cutoff frequency, as shown in Figure 37. This allows noise to be removed and partial discharge waveforms to be accurately received.

In the above-described embodiments, the two conductive elements 103 and 138 electrostatically coupled to the power line 102 or the neutral point lead 102 connected to the stator winding of the electric rotating machine are provided in a non-contact state. Even by providing a capacitor connected to the power supply line or the neutral point lead 102 instead of the conductive members 103 and 138, it is possible to remove noise and accurately receive the partial discharge waveform in a similar manner to the above.

In the ninth embodiment of the present invention, the power supply line is connected to the stator winding corresponding to one of the three phases of the electric rotating machine. Alternatively, the neutral lead can be connected to the neutral of the three-phase stator windings. Each of the at least two conductive elements or each of the at least two capacitors connected to the supply line or the neutral lead is electrically connected to a corresponding one of the input terminals of the two impedance transformers, wherein the at least two The conductive element has the same or different electrostatic coupling with the power line or the neutral point lead and does not touch the power line or the neutral point lead, and the two impedance transformers have different input impedance values and between the two impedances In a converter, the input impedance is greater than the output impedance. At the same moment as the peak detection moment of the pulse signal at the output of the impedance transformer with the smaller input impedance value, the output terminal of the impedance transformer with the larger input impedance value will be generated by one of the two impedance transformers. The pulse signal is determined to be a partial discharge signal. It is not necessary to change the internals of the rotating electrical machine. Non-contact sensors can be mounted to high voltage components relatively easily simply by changing the metal frame around the power wire or neutral lead of a rotating electrical machine. In addition, partial discharge can be detected with high detection sensitivity and accuracy.

Fig. 40 is a diagram showing a partial discharge detection device for a rotating electric machine according to a tenth embodiment of the present invention.

Referring to Fig. 40, the power line 102 is connected to the stator winding corresponding to one of the three phases of the electric rotating machine, or the neutral point lead 102 is connected to the neutral point of the three-phase stator winding. A conductive frame 151 having a rectangular parallelepiped shape or a cylindrical shape is provided around the power line or neutral point lead 102 .

The conductive frame 151 has an observation window 142 . A flat or circular insulating plate 144 is fixed to the viewing window 142 . The front or back surface of the insulating plate 144 supports a conductive element 145 that is electrostatically coupled to the power line or neutral lead 102 and is not in contact with the power line or neutral lead 102 . Furthermore, an impedance transformer 147 in which at least the input impedance is greater than the output impedance is supported on the insulating board 144 . The impedance converter 147 is connected to the signal processor 150 via the transmission line 148 .

An impedance transformer 147 selected according to the frequency band to be detected is connected to the conductive element 145 electrostatically coupled to the power line or the neutral point lead 102 so as to be fixed on the front surface of the insulating plate 144 of the observation window 142 of the conductive frame 151 or A high-pass filter is formed on the reverse surface, and the high-pass filter is represented by an equivalent circuit shown in Figs. 29 and 31 . This allows detection of partial discharge pulses.

Figure 41 shows the process and time required to install a partial discharge detection device. In conventional methods, coupling capacitors as conventional sensors are often mounted in racks as partial discharge detection sensors. In order to mount the sensor to the rotating electrical machine during operation, the following steps are required: stopping the rotating electrical machine, detaching the rack near the mounting point, installing the sensor and circuitry, and reinstalling the rack near the mounting point.

However, in the arrangement shown in FIG. 40, an insulating plate 144 supporting a conductive member 145 and an impedance transformer 147 is installed in the opening of the viewing window. In order to install the sensor, the following steps are necessary and sufficient: stop the rotating motor, separate the insulating plate 144 from the viewing window, and fit the insulating plate 144 onto the opening of the viewing window. This simplifies steps and reduces connection time compared to conventional methods.

As described above, in the tenth embodiment of the present invention, the conductive frame 151 having a rectangular parallelepiped shape or a cylindrical shape and having an observation window is provided around the stator winding of the rotary electric machine. The opening of the viewing window of the conductive frame 151 detachably supports the insulating plate 144 on which the conductive element 145 not in contact with the power line or the neutral point lead 102 and the conductive element 145 connected to the conductive element 145 and having an input impedance greater than the output impedance are fixed. The impedance transformer 147. Therefore, the partial discharge detection unit can be easily installed in a short time.

In the tenth embodiment, the conductive frame 151 is provided around the power line or the neutral point lead 102, as shown in FIG. 40 . For example, in an electric generator having a power line or neutral lead 102 and a grounded frame structure, placing the detection conductive element 145 in the frame covering the power line or neutral lead 102 may degrade the insulation properties. To prevent this from happening, a conductive element 145 is mounted on the viewing window 142 of the frame.

In this case, the distance between the conductive element 145 and the supply or neutral lead 102 is on the order of a few decimeters, although this also depends on the installation. The size of the observation window 142 is a few decimeters x a few decimeters. Therefore, on the basis of (dielectric constant 8.85pF/m×estimated area of the conductive member facing the power supply line 0.1×0.1m ² /distance between the conductive member and the power supply line 0.1m), the electrostatic capacitance C is about 1pF.

Assume that the input impedance Zin of the impedance converter 147 connected to the conductive element 145 having the electrostatic coupling as described above is 50,000Ω or more. According to equation (3) the cutoff frequency is about 3MHz. For this reason, accurate partial discharge detection not affected by noise is possible in a detection band corresponding to a frequency band of several MHz in which converter noise is reduced, as shown in FIG. 38 .

In the partial discharge detection method shown in FIG. 40, the observation window 142 may be larger, or the distance between the conductive member 145 and the power line 102 may be shorter in some cases. If it is assumed that the electrostatic coupling is as high as 10 pF, a cutoff frequency of about 3 MHz can be obtained by setting the input impedance of the impedance converter 147 to 5,000Ω or more.

A coaxial cable with a characteristic impedance of 50Ω or 75Ω is usually used as the transmission line 148 . For impedance matching, the output impedance of the impedance converter 147 is set to 50Ω or 75Ω.

As described above, the power line 102 is connected to the stator winding corresponding to one of the three phases of the electric rotating machine. Alternatively, the neutral lead 102 may be connected to the neutral of the three-phase stator windings. A conductive element having an electrostatic coupling of 10 pF or less to the power line or neutral lead 102 and not in contact with the power line or neutral lead 102 is electrically connected to the input of an impedance transformer having an input impedance of 5,000 Ω or greater . A partial discharge pulse signal is detected from an output of an impedance converter having an output impedance of 50Ω or 75Ω, or from an output of a transmission circuit having a characteristic impedance of 50Ω or 75Ω and connected to the output of the impedance converter for impedance matching. This enables partial discharge detection with high detection sensitivity and accuracy.

Even in this embodiment, as described above, it is possible to remove noise and accurately receive a partial discharge waveform by providing a capacitor instead of the conductive member 145 .

Fig. 42 is a diagram showing a partial discharge detection device for a rotating electric machine according to a thirteenth embodiment of the present invention.

As shown in FIG. 42, for example, in an electric power generator having a power line or a neutral point lead 102 and a conductive frame 151, a plurality of detecting conductive elements 152 and 153 will reduce the insulating properties. In order to prevent this from happening, a plurality of detection conductive elements 152 and 153 are arranged on the observation window 142 of the frame.

In this case, the distance between the test conductive elements 152 and 153 and the supply or neutral lead 102 is on the order of a few decimeters, although this is also device dependent. The size of the observation window 142 is a few decimeters x a few decimeters. Therefore, on the basis of (dielectric constant 8.85pF/m×estimated area of the conductive member facing the power supply line 0.1×0.1m ² /distance between the conductive member and the power supply line 0.1m), the electrostatic capacitance C is about 1pF.

Assume that the input impedance Zin of the impedance converter 154 connected to the detection conductive element 152 is 50,000Ω or more. According to equation (3) the cutoff frequency is about 3MHz. For this reason, partial discharge detection that is not affected by noise is possible in a detection band corresponding to a frequency band of several MHz or more in which converter noise is reduced, as shown in FIG. 38 .

However, since one pulse of partial discharge may have frequency components of several MHz or less in which noise is generated, the converter cannot completely reproduce the partial discharge pulse flowing to the power supply line 102 in some cases.

When the cutoff frequency (cutoff frequency II) is set to a low frequency band in which noise exists, as shown in FIG. 38 , an accurate partial discharge waveform can be detected. The cut-off frequency is 300kHz when the input impedance Zin of the impedance transformer 155 connected to the other detection conductive element 153 having about 1pF electrostatic coupling with the power line or neutral point lead 102 is 500,000Ω. The impedance converter 155 can accurately output the entire partial discharge waveform.

In the method shown in FIG. 40, the observation window 142 may be larger, or the distance between the detection conductive elements 152 and 153 and the power line 102 may be shorter in some cases. Assume electrostatic coupling up to 10pF. In order to set the cutoff frequency of the output signal from the impedance converter 154 to about 3 MHz, the input impedance of the impedance converter 154 is set to 5,000Ω or more. In order to set the cutoff frequency of the output signal from the impedance converter 155 to 300 kHz or more, the input impedance of the impedance converter 155 may be set to 50,000Ω or more.

Coaxial cables having a characteristic impedance of 50Ω or 75Ω are generally used as the transmission lines 167 and 168 . For impedance matching, the output impedances of the impedance converters 154 and 155 are set to 50Ω or 75Ω.

As described above, in the eleventh embodiment of the present invention, the partial discharge detecting device includes: two detecting conductive elements 152 and 153 having a voltage of 10 pF or more with respect to a power line or a neutral point lead connected to a stator winding of a rotating electric machine. Low electrostatic coupling and no contact with the power line or neutral lead; an impedance transformer 154 having an input impedance value of 5,000Ω or greater and an output impedance value of 50Ω or 75Ω; and an input impedance of 50,000Ω or greater Impedance converter 155 with an impedance value (that is, an input impedance value greater than that of the impedance converter 154 ) and an output impedance value of 50Ω or 75Ω. The detection conductive element 152 is electrically connected to an input terminal of an impedance transformer 154 . The other detecting conductive elements 153 are electrically connected to the impedance transformer 155 . A pulse signal generated from the output terminal of the impedance converter 155 at the same time as the peak detection timing of the pulse signal at the output terminal of the impedance converter 154 is determined as a partial discharge signal. This enables partial discharge detection with high detection sensitivity and accuracy.

Even in this embodiment, as described above, it is possible to remove noise and accurately receive the partial discharge waveform by providing two capacitors instead of the detection conductive members 152 and 153 .

Fig. 43 is a diagram showing a partial discharge detecting device for a rotating electric machine according to a seventeenth embodiment of the present invention.

Referring to Figure 43, a conductive element 103 is provided which is electrostatically coupled to a supply or neutral lead 102 which is connected to a stator winding 101 of a rotating electrical machine. As shown in FIG. 28 , the input terminal 106 of the impedance transformer 105 is electrically connected to the conductive element 103 via the lead wire 104 . The signal processor 160 receives the partial discharge pulse signal from the output 109 of the transmission line 108 connected to the output 107 of the impedance transformer 105 for impedance matching.

In addition, a coil 157 magnetically coupled to the supply line or neutral lead 102 is provided. A current detector 158 that outputs a voltage, such as a resistor, is connected to the coil 157 . The output of the current detector 158 is connected to the input 159 of the signal processor 160 through a transmission line.

As shown in Figure 44, the signal processor 160 has the following functions: according to the polarity of the pulse signal peak value (1) obtained from the output terminal 107 of the impedance converter 105 connected to the conductive element 103 and the current detected at the current connected to the coil 157 The product of the polarity of the peak (2) of the pulse signal induced in the detector 158 is positive or negative to distinguish the signal propagating from the rotating electrical machine from the signal propagating from the opposite side.

Figure 45A shows the pulse voltage waveform 161 of the partial discharge signal flowing to the outside from the stator winding of the rotating electrical machine through the power line 102 shown in Figure 43, and the pulse voltage waveform (P1) 162 at the output terminal 107 of the impedance converter 105, And the pulse voltage waveform ( P2 ) 163 induced in the current detector 158 of the coil 157 .

The waveform 163 induced in the coil 157 has a shape obtained by differentiating the waveform 161 of the power supply line 102 . The polarity of the pulse peak is equal to the polarity of the first wave. The coil 157 is arranged in such a direction that when a positive pulse signal flows from the rotating electric machine to the outside, the pulse peak has a positive polarity.

Figure 45B shows the pulse voltage waveform 164 of the partial discharge signal flowing from the outside through the power line 102 shown in Figure 43 to the stator winding of the rotating electrical machine, the pulse voltage waveform (P1) 165 at the output terminal 107 of the impedance converter 105, And the pulse voltage waveform (P2) 166 induced in the current detector 158 of the coil 157.

As shown in FIGS. 45A and 45B, the polarity of the voltage induced in the coil is reversed according to the flow direction of the partial discharge signal.

When a negative pulse signal flows to the power line, the polarity of the signal induced in the coil is opposite to that when a positive pulse signal flows to the power line. That is, as shown in FIGS. 44, 45A, and 45B, when the polarity of the pulse voltage waveform (P1) 162 or 165 at the output terminal 107 of the impedance converter 105 is consistent with the pulse induced in the current detector 158 of the coil 157 When the product of the polarities of the voltage waveform (P2) 163 or 166 is positive, the partial discharge signal flowing to the power line can be estimated to flow from the rotating electric machine to the outside. Signals flowing from the outside to the inside of the rotating electrical machine are identified as noise. Therefore, with the method shown in FIG. 44, detection can be performed while removing external noise.

As mentioned above, in the twelfth embodiment of the invention, there is provided at least one conductive element electrostatically coupled to the supply or neutral lead 102 connected to the stator winding 101 and at least one magnetically coupled to the supply or neutral lead 102 the coil. The signal propagating from the rotating electrical machine is compared with the signal propagating from outside the rotating electrical machine according to whether the polarity of the output signal peak from the impedance transformer connected to the conductive element is positive or negative multiplied by the polarity of the output signal peak induced in the coil differentiate. It is not necessary to change the internals of the rotating electrical machine. Non-contact sensors can be mounted to high voltage components relatively easily simply by changing the metal frame around the power wire or neutral lead of a rotating electrical machine. In addition, partial discharge can be accurately detected.

In the twelfth embodiment, a capacitor may be provided instead of the conductive element 103 . A resistor may be provided instead of the impedance converter 105 .

Fig. 46 is a diagram showing a partial discharge detecting device for a rotating electric machine according to a thirteenth embodiment of the present invention.

Referring to FIG. 46, the stator winding 101 corresponding to one of the three phases (one phase is shown in FIG. 46) of the electric rotating machine is stored in a slot formed in the stator core (not shown), and the The stator core is mounted to the inner surface of the stator frame 100 . Power lines 102 are connected to the stator windings 101 of each phase. Alternatively, the neutral lead 102 may be connected to the neutral of the three-phase stator windings. A support member (not shown) supports a non-contact conductive element 103 made of copper or aluminum and electrostatically coupled to the power or neutral lead 102 .

An electrical element 169 having an electrostatic capacitance Co is connected to the element 103, and an input terminal 106 of an impedance transformer 105 in which at least the input impedance Zin is greater than the output impedance Zout is electrically connected to the conductive element 103 via the lead 104. The partial discharge pulse signal is detected by inputting the detection signal from the output terminal 109 of the transmission line 108 (characteristic impedance Z ₀ ) to the signal processor 110 . The output terminal 109 is connected to the output terminal 107 of the impedance transformer 105 so as to match impedance.

A coaxial cable having a characteristic impedance of 50Ω or 75Ω is usually used as the transmission line 108 . Therefore, Zout is usually 50Ω or 75Ω.

Next, the function of the partial discharge detecting device of the rotating electrical machine having the above arrangement will be described.

FIG. 47 shows an equivalent circuit viewed from the power line or neutral point lead 102 in FIG. 46 . The power or neutral point lead 102 is connected in series with an electrostatic capacitance C and a parallel circuit comprising an electrostatic capacitance Co between the conductive element 103 and ground 111 and the input of an impedance transformer 105 grounded to ground 111 Impedance Zi. The ratio of the output Vo of the output terminal 107 of the impedance transformer 105 to the peak value Vi of the AC voltage at the supply line or neutral point lead 102 is given by

$\mathrm{<span\; class="notranslate">\; Vo</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; Vi</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; /</span>\sqrt{<span\; class="notranslate">\; \{</span>{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; co</span>}<span\; class="notranslate">\; /</span>\mathrm{<span\; class="notranslate">\; C</span>}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; +</span>{<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; /</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&pi;fCZ</span>}}_{\mathrm{<span\; class="notranslate">\; in</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ]</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; \}</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; )</span>$

Fig. 48 shows the frequency characteristic 170 [20*Log(Vo/Vin)] in Fig. 46 and Fig. 47, and this frequency characteristic is obtained by using an impedance converter whose input impedance Zin is greater than Zout and setting C=1pF, Co=10pF , obtained by Zin=50kΩ and Zout=50kΩ, Fig. 48 also shows the frequency characteristic 116 in Fig. 30 and Fig. 31, which is obtained by setting C=1pF and Z ₀ =50Ω without using an impedance transformer and obtained.

As is apparent from FIG. 48, in the partial discharge signal frequency band of several MHz or higher as shown in FIG. 38, compared with the detection method shown in FIG. The output gain is larger in the detection method in which the method shown in FIG. 30 does not use an impedance transformer and the method shown in FIG. 46 uses an impedance transformer 105 and an electrostatic capacitance Co connected to the conductive element 103.

FIG. 33 shows an equivalent circuit viewed from the signal processor 110 in FIG. 28 . A resistance value (Z ₀ ) 118 equal to characteristic impedance Z ₀ terminates both ends of transmission line 108 to prevent signals propagating in transmission line 108 from being reflected at terminals 107 and 109 .

That is to say, when the output impedance Zout of the impedance transformer ₁₀₅ shown in FIG _. to the signal processor 110.

In the embodiments described above, the conductive element electrostatically coupled to the power line or neutral lead 102 connected to the stator winding of the rotating electric machine is provided in a non-contact state. Even by providing a capacitor connected to the power line or the neutral point lead 102 instead of the conductive element, partial discharge can be detected as described above.

In the partial discharge detecting device for a rotating electrical machine according to the thirteenth embodiment, one end of the conductive member 103 or the capacitor connected to the power supply line or the neutral point lead 102 is connected to the input terminal of an impedance converter whose input impedance is larger than the output impedance, wherein The conductive member is electrostatically coupled to and is in a non-contact state with respect to the power line or neutral point lead 102 to have electrostatic capacitance with respect to the power line or neutral point lead 102 connected to the three phases corresponding to the rotating electrical machine. In one phase of the stator winding, the neutral point conductor 102 is connected to the neutral point of the three-phase stator winding. The partial discharge pulse signal may be detected from an output terminal of the impedance transformer or an output terminal of a transmission circuit connected to the output terminal of the impedance transformer so as to match impedance. It is not necessary to change the internals of the rotating electrical machine. Non-contact sensors can be mounted to high voltage components relatively easily simply by changing the metal frame around the power wire or neutral lead of a rotating electrical machine. In addition, partial discharge can be detected with high detection sensitivity and accuracy.

Industrial Applicability

The partial discharge detection device and detection method according to the present invention can facilitate installation in a non-contact state, and accurately perform partial discharge detection and insulation diagnosis, and help to formulate a suitable maintenance plan for a high-voltage rotating electrical machine and improve its reliability.

Claims (20)

1. the local discharge detection device of an electric rotating machine, it is characterized in that comprising: conducting element, its electrostatic coupling is to the neutral point lead-in wire that is connected to the neutral point with the threephase stator winding with the power lead that is connected corresponding to the stator winding mutually of one in the three-phase of electric rotating machine or electrostatic coupling, and do not contact with described power lead or neutral point lead-in wire; Impedance transformer, it has the input end of the output terminal that is electrically connected to described conducting element and has input impedance greater than its output impedance; And signal processing apparatus, be used to handle the detection signal that obtains from the output terminal of described impedance transformer detecting the Partial Discharge Detection pulse signal, and

The electrostatic capacitance of described conducting element and the input impedance of described impedance transformer have formed Hi-pass filter, so that from the output signal of described conducting element, obtain described Partial Discharge Detection pulse signal, and

The output impedance of described impedance transformer is configured to the input impedance matching with described signal processing apparatus.

2. the local discharge detection device of electric rotating machine according to claim 1, it is characterized in that: transmission circuit is connected to the described output terminal of described impedance transformer so that the output impedance of described impedance transformer and the input impedance of described transmission circuit are complementary, and makes described signal processing apparatus receive the detection signal that obtains from the output terminal of described transmission circuit.

3. the local discharge detection device of electric rotating machine according to claim 1, it is characterized in that: described conducting element and described impedance transformer are supported by insulcrete, described insulcrete is releasably attached on the view window in the conduction rack that is arranged on hollow, with described conduction rack be arranged on described power lead or neutral point lead-in wire around.

4. the local discharge detection device of electric rotating machine according to claim 1, it is characterized in that also comprising: corresponding to the coil of described conducting element magnetic coupling to described power lead or neutral point lead-in wire, and described signal processing apparatus is by being just or negative based on the product from the polarity of the output signal peak value of described impedance transformer and the polarity of the output signal peak value of responding in described coil, signal that differentiation is propagated from described electric rotating machine and the signal from described electric rotating machine external communication detect described local discharge signal.

5. the local discharge detection device of an electric rotating machine, it is characterized in that comprising: capacitor, one end are connected to the power lead that is connected corresponding to the stator winding mutually of one in the three-phase of described electric rotating machine or are connected to the neutral point lead-in wire that is connected with the neutral point of threephase stator winding; Impedance transformer, it has the input end of the other end that is connected to described capacitor and has input impedance greater than its output impedance; And signal processing apparatus, be used to handle the detection signal that obtains from the output terminal of described impedance transformer detecting the Partial Discharge Detection pulse signal, and

The electrostatic capacitance of described capacitor and the input impedance of described impedance transformer have formed Hi-pass filter, so that from the output signal of described capacitor, obtain described Partial Discharge Detection pulse signal, and

The output impedance of described impedance transformer is configured to the input impedance matching with described signal processing apparatus.

6. the local discharge detection device of electric rotating machine according to claim 5, it is characterized in that: transmission circuit is connected to the described output terminal of described impedance transformer so that the output impedance of described impedance transformer and the input impedance of described transmission circuit are complementary, and makes described signal processing apparatus receive the detection signal that obtains from the output terminal of described transmission circuit.

7. the local discharge detection device of electric rotating machine according to claim 5, it is characterized in that: described capacitor and described impedance transformer are supported by insulcrete, described insulcrete is releasably attached on the view window in the conduction rack that is arranged on hollow, with described conduction rack be arranged on described power lead or neutral point lead-in wire around.

8. the local discharge detection device of electric rotating machine according to claim 5, it is characterized in that also comprising: corresponding to the coil of described capacitor magnetic coupling to described power lead or neutral point lead-in wire, and described signal processing apparatus is by being just or negative based on the product from the polarity of the output signal peak value of described impedance transformer and the polarity of the output signal peak value of responding in described coil, signal that differentiation is propagated from described electric rotating machine and the signal from described electric rotating machine external communication detect described local discharge signal.

9. the local discharge detection device of an electric rotating machine, it is characterized in that comprising: at least two conducting elements with identical or different electric capacity, described conducting element electrostatic coupling is to corresponding to the stator winding of the phase in the three-phase of electric rotating machine or electrostatic coupling power lead or the neutral point lead-in wire to the neutral point that is connected to the threephase stator winding, and do not contact with described power lead or neutral point lead-in wire; At least two impedance transformers with different input resistance value, each impedance transformer have the input end that is electrically connected to corresponding one other end in the described conducting element, and have the input impedance greater than output impedance; And signal processing apparatus, be used to receive the detection signal that obtains from described impedance transformer, and the pulse signal that the detection of the peak value of the pulse detection signals that will obtain with the impedance transformer with less input impedance value from described impedance transformer obtains from the impedance transformer with big input impedance value constantly simultaneously is defined as local discharge signal.

10. the local discharge detection device of electric rotating machine according to claim 9, it is characterized in that: described conducting element and described impedance transformer are supported by insulcrete, described insulcrete is releasably attached on the view window in the conduction rack that is arranged on hollow, with described conduction rack be arranged on described power lead or neutral point lead-in wire around.

11. the local discharge detection device of electric rotating machine according to claim 9, it is characterized in that also comprising: corresponding to the coil of described conducting element magnetic coupling to described power lead or neutral point lead-in wire, and described signal processing apparatus is by being just or negative based on the product from the polarity of the output signal peak value of described impedance transformer and the polarity of the output signal peak value of responding in described coil, signal that differentiation is propagated from described electric rotating machine and the signal from described electric rotating machine external communication detect described local discharge signal.

12. the local discharge detection device of an electric rotating machine, it is characterized in that comprising: at least two capacitors, it has identical or different electric capacity and is connected to corresponding to the stator winding of the phase in the three-phase of electric rotating machine or is connected to power lead or the neutral point lead-in wire, and described power lead or neutral point lead-in wire are connected to the neutral point of threephase stator winding; At least two impedance transformers with different input resistance value, each impedance transformer have the input end that is electrically connected to corresponding one other end in the described capacitor, and have the input impedance greater than output impedance; And signal processing apparatus, be used to receive the detection signal that obtains from described impedance transformer, and the pulse signal that the detection of the peak value of the pulse detection signals that will obtain with the impedance transformer with less input impedance value from described impedance transformer obtains from the impedance transformer with big input impedance value constantly simultaneously is defined as local discharge signal.

13. the local discharge detection device of electric rotating machine according to claim 12, it is characterized in that: described capacitor and described impedance transformer are supported by insulcrete, described insulcrete is releasably attached on the view window in the conduction rack that is arranged on hollow, with described conduction rack be arranged on described power lead or neutral point lead-in wire around.

14. the local discharge detection device of electric rotating machine according to claim 12, it is characterized in that also comprising: corresponding to the coil of described capacitor magnetic coupling to described power lead or neutral point lead-in wire, and described signal processing apparatus is by being just or negative based on the product from the polarity of the output signal peak value of described impedance transformer and the polarity of the output signal peak value of responding in described coil, signal that differentiation is propagated from described electric rotating machine and the signal from described electric rotating machine external communication detect described local discharge signal.

15. the detection method for local discharge of an electric rotating machine, it is characterized in that comprising: the output terminal of conducting element is electrically connected to input impedance is not less than 500 Ω and output impedance is the input ends of 50 Ω to the impedance transformer of 75 Ω, described conducting element with corresponding to one in the three-phase of described electric rotating machine mutually stator winding or be connected to the power lead of neutral point of stator winding or the electrostatic coupling of neutral point lead-in wire is no more than 10pF, and do not contact with described power lead or neutral point lead-in wire; And detecting local discharge signal by handling the detection signal that obtains from the output terminal of transmission circuit, described transmission circuit has 50 Ω to the characteristic impedance of 75 Ω and be connected to the described output terminal of described impedance transformer so that matched impedance.

16. the detection method for local discharge of an electric rotating machine, described electric rotating machine comprises: two conducting elements, each described conducting element with corresponding to one in the three-phase of described electric rotating machine mutually stator winding or be connected to the power lead of neutral point of stator winding or the electrostatic coupling of neutral point lead-in wire is no more than 10pF, and do not contact with described power lead or neutral point lead-in wire; First impedance transformer has the input impedance value that is not less than 500 Ω and the 50 Ω output impedance value to 75 Ω; And second impedance transformer, having the input impedance value that is not less than 50,000 Ω and 50 Ω output impedance value to 75 Ω, the input impedance value of described second impedance transformer is greater than the input impedance value of described first impedance transformer;

The method is characterized in that: a conducting element is electrically connected to the input end of described first impedance transformer, and another conducting element is connected to the input end of described second impedance transformer; And, will detect the pulse signal of exporting from described second impedance transformer simultaneously constantly with the peak value of the pulse signal of exporting from described first impedance transformer and be defined as local discharge signal.

17. the detection method for local discharge of an electric rotating machine, it is characterized in that comprising: at least one conducting element or capacitor and at least one coil are set, described conducting element or capacitor electrostatic coupling are to going between to the neutral point that is connected with the neutral point of stator winding with power lead that is connected corresponding to the stator winding mutually of one in the three-phase of electric rotating machine or electrostatic coupling, and described at least one coil magnetic coupling is to described power lead or neutral point lead-in wire;

The impedance transformer that the electrostatic capacitance of described conducting element or capacitor is set and is connected to described conducting element or capacitor is to form Hi-pass filter, so that obtain described Partial Discharge Detection pulse signal from the output signal of described conducting element;

The output impedance of described impedance transformer is set to the input impedance matching with signal processing apparatus; And

By being just or negative based on product from the polarity of the output signal peak value of one of the resistor that is connected to described conducting element or described capacitor and described impedance transformer and the polarity of the output signal peak value of in described coil, responding to, signal that differentiation is propagated from described electric rotating machine and the signal from described electric rotating machine external communication detect local discharge signal.

18. the local discharge detection device of an electric rotating machine, it is characterized in that comprising: conducting element, its electrostatic coupling is to corresponding to the stator winding of the phase in the three-phase of described electric rotating machine or electrostatic coupling power lead or the neutral point lead-in wire to the neutral point that is connected to the threephase stator winding, and do not contact with described power lead or neutral point lead-in wire; The parallel circuit that comprises electrical equipment and impedance transformer, described electrical equipment has the electrostatic capacitance of the other end that is electrically connected to described conducting element, and described impedance transformer has the input impedance greater than output impedance; And signal processing apparatus, be used for detecting partial discharge pulse's signal by handling the detection signal that obtains from the output terminal of described impedance transformer.

19. the local discharge detection device of an electric rotating machine, it is characterized in that comprising: be connected to corresponding to the stator winding of the phase in the three-phase of electric rotating machine or be connected to power lead or the capacitor of neutral point lead-in wire, described power lead or neutral point lead-in wire are connected to the neutral point of threephase stator winding; The parallel circuit that comprises electrical equipment and impedance transformer, described electrical equipment has the electrostatic capacitance of the other end that is electrically connected to described capacitor, and described impedance transformer has the input impedance greater than output impedance; And signal processing apparatus, be used for detecting partial discharge pulse's signal by handling the detection signal that obtains from the output terminal of described impedance transformer.

20. the detection method for local discharge of an electric rotating machine, it is characterized in that comprising: in the metal frame of the stator frame that is connected to electric rotating machine, setting is corresponding to the power lead of threephase stator coil and one of them of neutral point lead-in wire that be connected to the neutral point of threephase stator coil, and described power lead or neutral point lead-in wire are propagated the local discharge signal that is produced by the degeneration of the described stator coil in the described stator frame; Two sensors are installed, each described sensor comprises around the tours antenna of described power lead or neutral point lead-in wire, make the separately predetermined distance of described sensor simultaneously, and described sensor is set or connects signal lead, so that make the peak value from the output pulse waveform of the described signal lead that is connected to described sensor have opposite polarity from described sensor; Regulate the length of the described signal lead of described sensor, so that make by the electric impulse signal induction that propagates into described power lead or neutral point lead-in wire along the direction that enters described electric rotating machine and output to the pulse signal that is connected to away from the signal lead terminal of the described sensor of described stator winding, arrive in the identical moment with pulse signal caused by the pulse signal that flows to described power lead or neutral point lead-in wire and that output to the signal lead terminal of the described sensor on the side that is connected to described stator coil; And the pulse waveform sum by obtaining via described two barss lead-in wire, detect the described local discharge signal that produces by the degeneration of described stator coil.

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