JPH0311978A - Gas-insulated water-cooled thyristor bulb - Google Patents

Abstract

PURPOSE:To measure a quantity of water at a high accuracy by building a corona detector in a thyristor bulb vessel. CONSTITUTION:Two or more thyristor bulbs 2 are provided in the inside of a gas-insulated thyristor bulb vessel 1 in which a material SF6 is placed. While a corona detector 3 is provided in the vessel 1 and connected in parallel to a voltage divider 4 which is connected in series to the before described bulbs 2. A generated amount of electric charge in the vessel is measured by a tuning corona measuring device 7 in the outside of the vessel 1 through a circuit, formed of a capacitor 5 and a resistor 6, and an amount of water is detected.

Description

Detailed Description of the Invention [Objective of the Invention] (Industrial Application Field) The present invention is directed to a gas insulator filled with SF6 gas used in direct current power transmission fi (HVDC), static static power compensator (SVC), etc. Concerning water-cooled thyristors and valves (prior technology) When moisture gets into gas-insulated equipment containing SF6, it accelerates insulation deterioration due to condensation on the surface of the insulating spacer and deterioration of insulation performance due to the combination of SF6 gas and moisture. may cause dielectric breakdown. Therefore, from the perspective of preventive maintenance, we regularly control the moisture content in the gas in the gas chamber, sample the SF6 gas in the sealed container and analyze it with a moisture analyzer, or use internal partial discharges built into the equipment. A method is used to detect abnormalities in advance using measuring devices.

In particular, the conventional partial discharge measurement device for gas-insulated equipment containing SF6 uses a detection electrode embedded inside an insulating spacer that insulates and supports a live part to generate corona caused by the amount of moisture in the SF6 gas adhering to the insulating surface. There is a method that measures changes in the corona level, and a method that measures changes in the corona level using corona pulses flowing through the ground wire of gas-insulated equipment containing SF6.

(Problems to be Solved by the Invention) Thyristor valves used in DC power transmission lines <1lVOc), static static power compensators (SVC), etc. are designed to have high voltage, large capacity, and be compact and lightweight. SF6
A method of insulating the thyristor valve by storing it in a sealed container is being considered from the viewpoint of reducing the size of the insulation and ensuring long-term stability.

Regarding cooling, consideration is being given to using water cooling, which has a proven track record in air and has excellent cooling efficiency.

The dielectric strength of the SF6 gas itself is not significantly affected by moisture in the SF6 gas, but if a solid insulator is present in the SF6 gas, the creeping insulation properties are affected by moisture adhering to the surface of the insulator. Regarding the water content in the SF6 gas and the creeping voltage characteristics on the surface of the insulator, if the amount of water can be controlled so that the dew point is 0°C or less, the deterioration in insulation can be almost ignored. This is because when the dew point of the moisture in the SF6 gas is 0° C. or lower, the moisture freezes and does not cause a decrease in insulation.

Based on these facts, the control value for the moisture content in SF6 gas of gas insulated equipment containing SF6 is based on the permissible value as the moisture content at the moisture dew point of 0°C in Sl'6 gas, and the control value for this as the moisture content in SF6 gas. This is the amount of water contained when the water dew point is -5°C or less.

Furthermore, since the S[6 gas pressure of each company is different, the applicable SF'6 gas pressure range is defined as 2.0 to 5.0 kg/-.'', and the following moisture management value is adopted.

Tolerance value = 1,000 ppn + (vol,) management value - 5
001) Dis(■0!,) On the other hand, the gas insulated water-cooled thyristor valve containing SF6 has a rated SF6 gas of 0.3bl.
Since the adoption of r/-.g can be omitted, if the moisture management value is calculated using the same concept as the conventional SF6 gas insulated equipment, it will be a relatively large value as shown below.

Tolerance value - 4,000 ppn (vol,) Management value - 3,0
00paIl (vol,) Figure 2 is a characteristic diagram showing the relationship between the amount of anal corona generated charge and the amount of moisture in SF6 gas.As is clear from the figure, as the amount of moisture in SF6 gas increases, the amount of corona generated charge increases. The amount tends to decrease.

As shown in Fig. 2, the conditions were that electrode plates with a thickness of 10 mm were arranged on an insulating support, and a voltage of 10 was applied to one of the electrodes, and the SF in that case was
The gas pressure in No. 6 is Okf/-.g, and the gas temperature is 11 to 13°C.

In the conventional measurement method, in order to distinguish between external noise and the object to be measured, the amount of charge generated by the object to be measured is approximately 100pc.
Considering the above requirements, there was a problem that the detection level was too low in the case of the control value.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a gas-insulated water-cooled thyristor valve equipped with a measuring means capable of detecting water content with high accuracy.

[Structure of the Invention (Means for Solving the Problem) In order to achieve the above object, the present invention provides a gas insulated water-cooled thyristor equipped with a means for detecting the amount of water in the thyristor valve container filled with Sr6 gas.・In the valve, corona detection consists of counter electrodes installed at a predetermined interval on an insulating support and connecting wires connected to each of the counter electrodes for the thyristor valve application circuit in the container. The corona detector was configured to be connected to a corona measuring device outside the container.

(Function) It is known that as the amount of water in SF6 gas increases, the amount of corona generated charge decreases. Therefore, by detecting a change in the amount of corona generated charge using a corona detector and a corona measuring device connected to the corona detector, the amount of water in the SF6 gas can be detected.

(Example) Examples will be described below with reference to the drawings.

FIG. 1 is a block diagram of one embodiment of a gas-insulated water-cooled syrisk valve according to the present invention. In Figure 1, 1 is SF
This is a thyristor valve container containing six gases, and a plurality of thyristor valves 2 are connected in series to a power source (not shown) inside. The other is a corona detector (described later), which is connected across the terminals of a voltage divider 4 connected in series with the thyristor valve 2. Also, there is a capacitor 5 in the corona detector unit.
A circuit consisting of a resistor 6 and a resistor 6 are connected in parallel outside the container, and a tunable corona measuring device 7 is further connected between the terminals of the resistor 6 via a circuit such as a resistor.

FIG. 3 is a block diagram of the corona detector, with FIG. 3(a) being a plan view and FIG. 3(b) being a side view. As shown in the figure, the corona detector unit includes a plate-shaped insulating support (hereinafter referred to as an insulating plate) 30, and a plate-shaped facing f! 31 and a connection line 32 connected to the counter electrode.

Next, I will explain the effect.

First, the voltage of the thyristor valve is applied to the corona detector via the voltage divider 4, and corona is generated when the corona is detected. The amount of charge generated by this corona changes depending on the amount of moisture in the SF6 gas, as shown in FIG.

The amount of generated charge is measured by a tunable corona measuring device 7 via a circuit including a capacitor 5 and a resistor 6 connected in parallel.

As mentioned above, SF6 gas insulated water cooled thyristor
An insulating plate 30 is installed inside the valve container 1 at a predetermined interval on the insulating plate; By providing a corona detection circuit consisting of a plate-shaped counter electrode 31 and a connecting wire 32 connected to the counter electrode, an SF6 gas-insulated water-cooled silica
The amount of moisture in the SF6 gas inside the valve container 1 can be determined.

FIG. 4 is a block diagram of another embodiment.

In this embodiment, the voltage divider 4 is constituted by a capacitor, and a resistor 8 is further connected in series with this, and a tunable corona measuring device is connected to the end of this resistor. The other configurations are the same as in FIG. 1.

With the above configuration, it is possible to reduce the terminal voltage of the resistor output to the outside of the SF6-containing gas-insulated water-cooled thyristor valve container 1 to several tens of volts or less, making it easier to handle the gas-insulated water-cooled thyristor valve. is obtained.

FIG. 5 is a block diagram of still another embodiment.

In this embodiment, only a corona detector 8 is installed in the thyristor pulp chamber Bl, and a circuit consisting of a capacitor 5 and a resistor 6 is connected in parallel with the corona detector 3 outside, and a tunable corona detector is connected to the resistor 6 in parallel with the corona detector 3. A measuring device 7 is connected to it. Note that 9 is an AC power source.

With the above configuration, the voltage applied to the corona detection 8 can be made into a sine wave, unlike the voltage waveform of the thyristor valve. This enables highly accurate measurement without being affected by thyristor valve body noise. Furthermore, since it is possible to apply a voltage to the corona detector unit only during measurement, it is possible to suppress the production of decomposed gas due to corona, which is always generated, and to prevent electrical damage without affecting other components. The amount of moisture in SF6 gas can be measured.

[Effects of the Invention] As explained above, according to the present invention, a corona detector is incorporated into a thyristor valve container containing SF6 gas,
Since the corona detector is configured to measure the degree of corona generation, it is possible to provide a gas-insulated water-cooled thyristor valve that can measure moisture in SF6 gas with high accuracy.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram of an embodiment of the gas insulated water-cooled thyristor valve according to the present invention, Fig. 2 is a characteristic diagram showing the relationship between the Sf6 scum water content and the amount of corona generated charge, and Fig. 3 is a corona detector. FIG. 4 is a schematic diagram of another embodiment, and FIG. 5 is a diagram of still another embodiment. 1... Thyristor/valve container 2... Thyristor/valve unit... Corona detector 4... Voltage divider 7... Tunable corona measuring device

Claims (1)

[Claims] In a gas-insulated water-cooled thyristor valve having means for detecting the amount of water in a thyristor valve container filled with SF6 gas, a predetermined portion on an insulating support is provided for a thyristor valve application circuit located in said container. By incorporating a corona detector consisting of counter electrodes installed at intervals of A gas insulated water cooled thyristor valve characterized by detecting the amount of water corresponding to the amount of water.