JPH0553288B2 - - Google Patents

Description

Detailed Description of the Invention [Objective of the Invention] (Industrial Field of Application) The present invention relates to a gas leak detection device for gas-insulated electrical equipment, and in particular, the present invention relates to a gas leak detection device for gas-insulated electrical equipment. The present invention relates to a gas leak detection device that determines gas leakage.

(Prior Art) Urban construction facilities such as buildings, underground malls, transportation facilities, and public facilities are becoming larger and more complex, and there is a need to strengthen fire prevention and disaster prevention measures. In addition, there is an increasing demand for the power receiving and substation equipment installed in these facilities to be more compact and nonflammable, and sulfur hexafluoride (SF ₆ ) gas, which is a nonflammable, harmless, and non-polluting insulating gas, is being used as the insulating medium. Gas-insulated electrical equipment such as gas-insulated switchgear, reactors, and transformers are now being applied.

These gas-insulated electric devices have an insulating gas sealed in a tank together with the main body of the electric device at a predetermined pressure, and this insulating gas serves to insulate and cool the electric device. Therefore, if this insulating gas leaks to the outside of the tank for some reason,
In terms of insulation, cooling, etc., it has a significant impact on the performance of electrical equipment, and in some cases, it may be necessary to stop the operation of electrical equipment.

Conventional gas-insulated electrical equipment is equipped with a gas density switch as a gas leak detection device for monitoring leaks of insulating gas from such tanks. This gas density switch not only simply detects the pressure of the insulating gas, but also corrects this pressure based on the ambient temperature and monitors that a specified gas pressure (gas density) is always maintained. Gas-insulated electrical equipment has an insulating gas sealed inside the tank at a predetermined pressure, so the gas pressure inside the tank changes depending on the temperature of the insulating gas, making it difficult to detect just the gas pressure. ,
Unable to detect insulating gas leak.

FIG. 3 is a conceptual diagram for explaining the principle of a conventional gas density switch. A gas pipe 3 is installed in a tank 2 of a gas-insulated electric device that needs to detect gas leaks, and the pressure of the insulation 1 in the tank 2 is transmitted to a predetermined position, and the pressure is maintained at a certain temperature at a certain temperature. A standard gas filled tank 5 filled with a standard gas 6 is provided, and the respective gas pressures are sent to a differential pressure detection device 4 that detects the differential pressure between the gas pressure in the tank 2 and the gas pressure in the standard gas filled tank 5. Gas pipes 3 are connected so as to communicate, and a differential pressure detection device 4 and a standard gas filled tank 5 are housed in a density switch storage box 7.

Since the ambient temperature of the standard gas filled tank 5 and the temperature of the insulating gas in the tank 2 are approximately the same, changes in ambient temperature due to climate etc. will have the same effect on the pressure of the standard gas 6 and the gas pressure in the tank 2. As long as the pressure difference between the two is detected, the influence of ambient temperature changes will not appear.

However, if the insulating gas 1 inside the tank 2 leaks out of the tank 2 for some reason, the differential pressure will naturally change, so gas leakage can be detected by detecting this change. .

(Problems to be Solved by the Invention) FIG. 2 shows that the contents of a transformer are constructed by winding a winding 11 around an iron core 10, and that the contents of the transformer are stored in a transformer tank 9 and an insulating gas 12 is provided. A conceptual diagram of a gas insulated transformer sealed within a transformer tank is shown.
The transformer tank 9 is equipped with a cooler 8 for cooling the insulating gas 12.

In the gas insulated transformer shown in FIG. 2, it is also necessary to monitor leakage of the insulating gas 12 sealed in the transformer tank 9 in order to maintain insulation and cooling characteristics. As mentioned above, gas leaks cannot be detected simply by detecting gas pressure, so it is necessary to correct gas pressure using gas temperature. However, in the conventional gas density switch, the pressure is compensated by the gas temperature at the temperature around the standard gas-filled tank 5, but in the case of a gas insulated transformer, the winding 11,
The losses occurring within the core 10 warm the insulating gas 12 to a temperature higher than the surrounding outside temperature. Generally, this temperature is about 20 to 50 degrees Celsius, and conventional gas density switches are unable to accurately compensate for pressure based on gas temperature, making it impossible to detect gas leaks with high precision.

The present invention has been made in consideration of the above points, and
The purpose is to provide a gas leak detection device for gas insulated electrical equipment that can detect gas leaks with high accuracy when there is a temperature difference between the gas temperature of the gas insulated electrical equipment and the surrounding outside air temperature. It is in.

[Structure of the invention]

(Means for Solving the Problems and Their Effects) In order to achieve the above object, the present invention provides a device for measuring the average temperature of the insulating gas in the tank of gas-insulated electrical equipment and a device for measuring the pressure of the insulating gas. The present invention is characterized in that a measuring device is attached, the gas density is calculated by a calculation device from the average temperature of the insulating gas and the gas pressure, and gas leakage is detected with high accuracy by monitoring this gas density.

(Example) An example of the present invention will be described below with reference to FIG.

As shown in FIG. 1, a gas insulated transformer is constructed by storing the contents of a transformer, which is constructed by winding a winding 11 around an iron core 10, in a transformer tank 9, and filling insulating gas 12 at a predetermined pressure. Gas temperature detectors 14 are installed at the top and bottom of the transformer tank 9 to detect the average temperature of the insulating gas 12, and a pressure detector 14 is installed on the top surface of the transformer tank 9 to detect the pressure of the insulating gas 12. 13 is attached.

The upper and lower insulating gas temperatures in the transformer tank 9 are sent via a temperature information transmission path 16 to a calculation device 17 that calculates the average gas temperature, and the average gas temperature is determined by simple arithmetic averaging or an appropriate calculation. Calculate. In addition, the insulating gas pressure is determined by the pressure detection unit 13.
is detected and sent via the pressure information transmission line 15 to the calculation device 19 that calculates the gas density. The average gas temperature calculated by the calculation device 17 is also simultaneously sent to the calculation device 19 via the transmission line 18, and the gas density is accurately calculated in the calculation device 19 from the average gas temperature and gas pressure. The gas density corresponds to the number of gas molecules, and the gas density remains unchanged even if the pressure changes due to changes in the ambient temperature. Here, the volume of the insulating gas 12, which is another important element for calculating the gas density, is constant because gas-insulated electrical equipment is sealed, and can be set in advance in the calculation device 19 as a constant. It is. The calculated gas density is transmitted to the gas density determining device 21 via the gas density information transmission path 20. In the gas density determining device 21, a specified insulating gas density initially sealed in the gas-insulated electrical equipment is set in advance, and this specified value is compared with the gas density obtained by calculation. Pressure detector 1
3 and the error of the temperature detector 14, when making a comparison, give an appropriate range of error in the gas density.
When the difference in gas density deviates from this range, it is determined that there is an abnormality in the gas density.

When calculating the average gas temperature, it is also possible to measure an arbitrary constant gas temperature in the tank 9 that is considered to be at the average gas temperature and use it as the average gas temperature, and 2. It is also possible to measure the insulating gas temperature at measurement points exceeding the above points and calculate the average gas temperature with higher accuracy by performing appropriate calculations. It goes without saying that the point at which the gas pressure is measured is not limited to the top surface of the tank, and can be measured at any arbitrary point.

〔Effect of the invention〕

As described above, according to the present invention, in a gas leak detection device for gas-insulated electrical equipment in which an insulating gas is housed in a tank at a predetermined density together with the main body of the electrical equipment, gas temperature detection detects the average gas temperature in the tank. a gas pressure detector for detecting the gas pressure in the tank, and a calculation device for calculating the density of the insulating gas from the average gas temperature and the gas pressure, and the gas density determined by the calculation device is provided. This gas leak detection device for gas insulated electrical equipment can detect gas leaks with high accuracy even when there is a temperature difference between the temperature of the insulating gas and the surrounding outside air temperature. can be obtained.

[Brief explanation of drawings]

Figure 1 is a front view showing one embodiment of the present invention, Figure 2 is a front view showing one embodiment of the present invention;
The figure is a front view showing a schematic configuration of a gas insulated transformer, and FIG. 3 is a front view showing a conventional gas insulated electric device. 9...Transformer tank, 10...Iron core, 11...
Winding wire, 13...Pressure detector, 14...Temperature detector, 17, 19... Arithmetic device, 21... Gas density determination device.

Claims (1)

[Claims] 1. A gas leak detection device for gas-insulated electrical equipment in which an insulating gas is housed in a tank at a predetermined density along with the main body of the electrical equipment, including a gas temperature detector for detecting the average gas temperature in the tank, and a gas temperature detector for detecting the average gas temperature in the tank; It consists of a gas pressure detector that detects pressure, and a calculation device that calculates the density of the insulating gas from the average gas temperature and gas pressure. Gas leakage can be detected by monitoring the gas density determined by this calculation device. A gas leak detection device for gas insulated electrical equipment, characterized in that it detects a gas leak.