JPH08105811A - Gas leak monitoring apparatus for gas breakage electric equipment - Google Patents

Abstract

PURPOSE: To provide a monitoring apparatus inexpensive and easy to maintain which makes possible early detection of a gas leak by always accomplishing a highly accurate temperature correction of an actual measured value of a gas pressure detected with a gas pressure sensor to determine a gas pressure conversion value at a reference temperature without being affected by turbulence such as energized current, sunshine, wind and rain. CONSTITUTION: A closed tank 1 of gas breakage electric equipment is provided with a gas pressure sensor 4 to detect a pressure of an insulation gas 3 sealed and a temperature sensor 7 for detecting the temperature of the surface of a partition 6 is provided inside a box 5 adjoining the closed tank 1 and on the surface of the partition separating the closed tank 1 from the box 5. A temperature correcting means 9 is provided to correct an actually measured value of a gas pressure by the surface temperature of the partition with the temperature sensor 7 and calculates a gas pressure conversion value at a reference temperature. A gas leak judging means 10 is provided to judge the presence of a gas leak by comparing the gas pressure conversion value calculated with a criterion value set previously.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas leakage monitoring device for gas insulated electrical equipment for monitoring the leakage of insulating gas sealed in a closed tank such as a gas insulated switchgear.

[0002]

2. Description of the Related Art Insulating gas such as sulfur hexafluoride enclosed in gas-insulated electrical equipment electrically insulates electrical components such as current-carrying parts from a sealed tank and cools the sealed tank by convection. It has a function to do. Therefore, since the leakage of the insulating gas has a great influence on the performance of the electric device, it has been conventionally monitored using a gas density switch.

Further, in recent years, a gas leak monitoring device combining a gas pressure sensor and an air temperature sensor as shown in Japanese Patent Laid-Open No. 3-222613, and a maximum gas temperature as shown in Japanese Patent Laid-Open No. 4-192509. A gas leak detection device for detecting gas pressure and load factor has been introduced.

[0004]

Of the above-mentioned conventional techniques,
In monitoring using a gas density switch, the gas density switch may be installed at a location corresponding to the gas average temperature, but in reality, the temperature distribution in the closed tank is due to internal heat generation due to energizing current and disturbances such as solar radiation, wind and rain. There is a problem that an error occurs due to a complicated change due to the influence, a malfunction occurs when the judgment value of gas leak is strict, and a detection of gas leak is delayed when the judgment value is loosened. In addition, this method is a method of issuing an alarm for the first time when a predetermined judgment value set in advance is reached, and gas pressure is constantly monitored and a minute gas leak is judged early from its decreasing tendency, It was difficult to systematically take measures such as investigation of gas leaks, repairs, and supplementation of insulating gas.

In order to improve the above-mentioned problems, a device for constantly detecting the value of gas pressure using a gas pressure sensor has been introduced. However, since the gas pressure changes depending on the temperature,
It is difficult to determine whether the gas pressure drop is due to a temperature drop or a gas leak. That is, in the gas leak monitoring device in which the gas pressure sensor and the air temperature sensor are combined, since the correction is performed by using the outside air temperature as a substitute for the gas average temperature, the energization current is small, and it is not affected by solar radiation or wind and rain. Is a prerequisite for gas leak judgment, and there are restrictions on application. Further, in the device for detecting the maximum gas temperature, the gas pressure, and the load factor, in order to obtain the gas average temperature from the load factor that changes with time, a complicated operation considering the heat capacity of the electric device and the time constant of the temperature change is complicated. Calculation processing is required, the monitoring device becomes expensive, and errors due to the effects of sunlight and wind and rain are unavoidable. In addition, since the temperature detector that measures the maximum gas temperature is installed in a closed tank, it is necessary to stop the electric equipment and perform gas processing when inspecting, repairing, or replacing the temperature detector, which is troublesome for maintenance. I needed it.

Therefore, an object of the present invention is to constantly perform a highly accurate temperature correction on a measured value of gas pressure detected by a gas pressure sensor without being affected by disturbances such as a current flow, solar radiation, and wind and rain to obtain a reference temperature. It is an object of the present invention to provide a low-cost and easy-to-maintain monitoring device capable of obtaining a gas pressure conversion value in (1) and detecting a gas leak at an early stage.

[0007]

According to the present invention, a gas pressure sensor for detecting the pressure of a sealed insulating gas is provided in a sealed tank of a gas-insulated electric device, and a gas is sealed inside a box adjacent to the sealed tank. A temperature sensor for detecting the partition wall surface temperature is provided on the surface of the partition wall that separates the tank and the box. Furthermore, the gas pressure measured value detected by the gas pressure sensor,
Corrected by the partition wall surface temperature detected by the temperature sensor, a temperature correction means for calculating a gas pressure conversion value at the reference temperature is provided, and the calculated gas pressure conversion value is compared with a preset judgment value. Gas leak determining means for determining the presence or absence of gas leak is provided.

[0008]

According to the monitoring device of the present invention configured as described above, the partition wall surface temperature is used when the gas pressure measured value is corrected to calculate the gas pressure conversion value at the reference temperature. It is possible to reduce the influence of disturbances such as solar radiation and wind and rain. That is, when the gas average temperature rises above the outside air temperature due to internal heat generation due to the energizing current, the partition wall surface temperature also rises due to heat conduction in the partition thickness direction, so the gas average temperature is indirectly detected on the partition wall surface. be able to. In addition, when the gas average temperature changes from the outside air temperature due to the influence of disturbance such as solar radiation or wind and rain, these disturbances have the same effect not only on the sealed tank but also on the adjacent box, so insulating gas in the sealed tank, The air inside the box and the partition wall separating the two trace the same temperature history, and the gas average temperature can be indirectly detected on the surface of the partition wall.
In practice, the above-mentioned energizing current and the disturbance are overlapped at the same time to affect the gas average temperature, but by using the partition wall surface temperature, it is possible to perform highly accurate temperature correction without being affected by these. Gas leaks can be detected early.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment of a gas leakage monitoring device for gas insulated electric equipment according to the present invention. Insulation tank 3 of the gas-insulated electrical equipment is electrically isolated from electrical component 2 in closed tank 1 by insulating gas 3 in order to cool the inside of closed tank 1 by convection. It is sealed by pressure. To detect this gas pressure,
The gas pressure sensor 4 is provided in the closed tank 1 by using a pipe, a flange and the like. On the other hand, inside the box 5 adjacent to the closed tank 1, on the surface of the partition wall 6 separating the closed tank 1 and the box 5,
A temperature sensor 7 for detecting the partition wall surface temperature is provided. Also,
The electric signals output from the gas pressure sensor 4 and the temperature sensor 7 are taken in, and the gas pressure actual measurement value output from the gas pressure sensor 4 is corrected by the surface temperature of the partition wall 6 output from the temperature sensor 7 to obtain the reference temperature at the reference temperature. A temperature correction means 9 for calculating a gas pressure conversion value is provided. Further, the temperature correction means 9
A gas leak determination means 10 is provided for fetching the temperature-corrected gas pressure converted value output from the device and comparing the gas pressure converted value with a preset determination value to determine the presence or absence of gas leakage.

The gas pressure sensor 4 is a semiconductor type strain gauge or a pressure gauge with a potentiometer, the temperature sensor 7 is a platinum resistance thermometer or a thermocouple, and the temperature correction means 9 and the gas leakage determination means 10 are microprocessors or the like. A personal computer or the like is used.

Next, a method for monitoring gas leakage in the embodiment configured as described above will be described. Since the gas pressure inside the closed tank 1 changes depending on the gas average temperature as shown by the curve A in FIG. 2, the rated enclosed gas pressure is normally the state 0 in FIG. 2, that is, at the reference temperature t0. It is expressed by the gas pressure P0. During actual equipment operation, in addition to changes in the outside air temperature, the average gas temperature changes intricately under the influence of disturbances such as current flow, solar radiation, and wind and rain.
The gas pressure also changes accordingly. Assuming now that the equipment has a gas average temperature t1 and a gas pressure P1 corresponding to the state B of FIG. 2, the gas pressure sensor 4 and the temperature sensor 7 detect the pressure P1 and the temperature t1, respectively,
An electric signal corresponding to this is output. The temperature correction means 9 can obtain the gas pressure conversion value P2 at the reference temperature t0 shown in the state C of FIG. 2 by taking in these electric signals and using a predetermined correction formula. Gas leak determination means 1
When the gas pressure conversion value P2 is smaller than the preset judgment value PN, it is judged that there is a gas leak, and an abnormality notification such as contact output or lamp lighting is performed.

In the above gas leakage monitoring method, accurate determination of the average gas temperature is essential for highly accurate temperature correction, and the effectiveness of determining the temperature at the surface of the partition wall 6 will be described below. Sealed tank 1 by energizing current
If heat is generated inside the chamber, the gas temperature T of the insulating gas 3
G, the partition wall surface temperature TW of the partition wall 6, and the air 8 in the box 5
The air temperature TI is higher than the outside air temperature TO, and exhibits a temperature distribution as schematically shown in FIG. 3 in accordance with the respective heat resistance and convection heat transfer characteristics. At this time, the gas temperature TG is different in the height direction of the closed tank 1, and the gas average temperature TG0 is usually obtained near the center of the closed tank 1. When the partition wall 6 is relatively thin, its thermal resistance is small and the temperature drop ΔT in the thickness direction of the partition wall 6 is small, so the temperature TW0 near the center of the partition wall 6 is small.
Almost coincides with the average gas temperature TG0. As the partition wall 6 becomes thicker, the temperature decrease ΔT becomes larger and cannot be ignored. To remove the error due to this temperature drop ΔT, 2
There are two possible ways. The first is a method of obtaining a temperature TW0 near the center of the partition wall 6 and adding a value corresponding to the temperature decrease ΔT, and the second is a method of adding the partition wall 6 as shown in FIG.
Of the partition wall surface temperature TW1 corresponding to the gas average temperature TG0 at a position higher than the center of the temperature sensor 7
Is a method of providing. The value corresponding to the temperature decrease ΔT in the first method and the location where the partition wall surface temperature TW1 in the second method can be obtained can be experimentally obtained by using an actual electric device. By using any one of the above methods, even if the partition wall 6 is thick, by detecting the partition wall surface temperature TW1, the gas average temperature TG0 when the energizing current is flowing can be obtained.

Next, the case where there is a disturbance such as solar radiation or wind and rain will be described. In the gas-insulated electrical equipment installed outdoors, the temperature of the outer wall of the closed tank 1 and the box 5 rises due to radiative heat transfer due to solar radiation, and along with this, the insulating gas 3 inside the closed tank 1 and air 8 inside the box 5 Temperature also rises. On the contrary, when there is the effect of wind and rain, these temperatures fall. At this time, the influence of the disturbance has the same effect on the closed tank 1 and the box 5, so that the gas temperature and the air temperature in the box 5 have similar temperature histories. Therefore, since the partition wall surface temperature of the partition wall 6 existing in the middle also follows a similar temperature history,
The gas temperature changed due to the influence of disturbance can be indirectly obtained.

Strictly speaking, the temperature history of the gas temperature and the air temperature in the box 5 described above is different in the shape and material of the closed tank 1 and the box 5, the thickness, and the thermal characteristics of the insulating gas 3 and the air 8. Therefore, there is a case where the partition wall surface temperature cannot be regarded as a gas temperature as it is. In this case, the error between the partition wall surface temperature and the gas temperature may be experimentally obtained in advance, and the error may be compensated when the temperature of the gas pressure is corrected by the temperature correction means 9.

As described above, by detecting the partition wall surface temperature, the average gas temperature can be accurately obtained without being affected by disturbances such as a current flowing, solar radiation, and wind and rain. Therefore, perform highly accurate temperature correction of gas pressure,
Gas leaks can be detected early.

[0016]

According to the present invention, since the temperature of the gas pressure is corrected at the partition wall surface temperature corresponding to the gas average temperature, the accuracy of the correction can be improved and the gas leak can be detected early. In addition, since secondary signals such as load factor are not required, the monitoring device can be simplified and the cost can be reduced by simplifying the arithmetic processing, and the temperature sensor in the sealed tank is not required. Is also easy.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of a gas leakage monitoring device for gas insulated electrical equipment according to the present invention.

FIG. 2 is a diagram showing a method for temperature correction of gas pressure according to the present invention.

FIG. 3 is a diagram showing a method for obtaining a gas average temperature according to the present invention.

[Explanation of symbols]

 1 Airtight Tank 2 Electrical Components 3 Insulating Gas 4 Gas Pressure Sensor 5 Box 6 Partition 7 Temperature Sensor 8 Air Inside Box 9 Temperature Corrector 10 Gas Leakage Judge

Front page continuation (72) Takehiko Yamada Inventor Takehiko Yamada 3-1-1 Yoshino-cho, Nishibiwajima-cho, Nishikasugai-gun, Aichi Takadake Works Nagoya Works

Claims (1)

[Claims] 1. A gas-insulated electric device in which an electric component such as a current-carrying part is housed in a sealed tank, and an insulating gas is sealed in a gap at a predetermined pressure. A gas pressure sensor for detecting the pressure of the insulating gas, inside the box adjacent to the closed tank, provided on the surface of the partition wall separating the closed tank and the box, a temperature sensor for detecting the partition wall surface temperature, the gas The gas pressure conversion value calculated by correcting the gas pressure measurement value detected by the pressure sensor with the partition wall surface temperature detected by the temperature sensor and calculating the gas pressure conversion value at the reference temperature is preset. A gas leak monitoring device for gas insulated electrical equipment, comprising: a gas leak judging means for judging the presence or absence of a gas leak by comparing it with a predetermined judgment value.