JPH08105813A - Gas leak detector for gas-insulated switch gear - Google Patents

Abstract

PURPOSE: To provide an inexpensive monitoring apparatus which makes possible early detection of a gas leak by accomplishing a highly accurate temperature correction of individual gas pressures detected with a plurality of gas pressure sensors without being affected by energized current to determine a gas pressure conversion value at a reference temperature CONSTITUTION: A plurality of closed tanks 1A-1C of a gas-insulated switch gear are provided with gas pressure sensors 4A-4C respectively and a surface temperature sensor 5 is provided on the surface of an external wall of any one closed tank 1C, an air temperature sensor 6 is provided near the gas- insulated switch gear and auxiliary contacts 8A and 8B are provided to output the state of the switching parts 7A and 7B. A temperature correction means 9 is provided to fetch output signals of the gas pressure sensor 4A-4C, the surface temperature sensor 5 and the air temperature sensor 6 so that the presence of energized current is recognized from the state of the auxiliary contacts 8A and 8B to calculate a gas pressure conversion value at a reference temperature and a gas leak judging means 10 is provided to judge the presence of a gas leak by comparing the gas pressure conversion value 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 a gas insulation switchgear for monitoring the leakage of insulating gas sealed in a closed tank.

[0002]

2. Description of the Related Art An insulating gas such as sulfur hexafluoride enclosed in a gas-insulated switchgear has a function of electrically insulating a high-voltage conductor and an opening / closing part from a sealed tank and cooling the inside of the sealed tank by convection. I have it. Therefore, since the leakage of the insulating gas has a great influence on the performance of the switchgear, the gas density switch is conventionally used for monitoring.

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,
For monitoring using a gas density switch, the gas density switch may be installed at a location corresponding to the average gas temperature, but in reality the temperature distribution inside the sealed tank changes intricately due to the internal heat generated by the energizing current. Therefore, an error occurs, and if the judgment value of gas leakage is made strict, malfunction occurs, and if the judgment value is loosened, detection of gas leakage is delayed. 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 slight 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, in order to perform correction by using the outside air temperature as a substitute for the gas average temperature, it is a premise at the time of gas leak determination that the internal heat generation due to the energization current is small. 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. Since the number of sensors and the amount of data are large due to the necessity of arithmetic processing and the need to provide a temperature sensor in each closed tank, the monitoring device is expensive.

Therefore, an object of the present invention is to obtain a gas pressure conversion value at a reference temperature by highly accurately correcting the respective gas pressures detected by a plurality of gas pressure sensors without being affected by the energizing current. An object of the present invention is to provide an inexpensive monitoring device capable of detecting a gas leak at an early stage.

[0007]

SUMMARY OF THE INVENTION In the present invention, a gas pressure sensor for detecting the pressure of insulating gas enclosed in a plurality of closed tanks of a gas-insulated switchgear for accommodating a high-voltage conductor having a branch part and an opening / closing part. A surface temperature sensor for detecting the outer wall surface temperature is provided on the surface of any one of the outer walls of the closed tank, and an air temperature sensor for detecting the outer air temperature is provided near the gas-insulated switchgear. Further, the output signals of the respective gas pressures detected by the plurality of gas pressure sensors, the outer wall surface temperature detected by the surface temperature sensor, and the outside air temperature detected by the temperature sensor are fetched, and a conducting current flows through the high-voltage conductor. The temperature of the outer wall surface is regarded as the gas average temperature in the closed tank, and the outside air temperature is regarded as the gas average temperature in the closed tank in which the energizing current does not flow in the high-voltage conductor, and the temperature correction means for calculating the gas pressure conversion value at the reference temperature is calculated. Provided is gas leakage determination means for comparing the calculated gas pressure conversion value with a determination value set in advance to determine the presence or absence of gas leakage.

[0008]

According to the monitoring apparatus of the present invention configured as described above, when the gas pressure is corrected and the gas pressure conversion value at the reference temperature is calculated, the temperature used for the correction is determined by the presence or absence of the energizing current. By selecting the surface temperature or the outside air temperature, it is possible to eliminate the influence of the energizing current. That is, in a closed tank in which a current is flowing through the high-voltage conductor,
Since the rise of the gas average temperature due to the energizing current raises the wall temperature of the closed tank, the surface temperature sensor provided on the surface of the outer wall can detect the gas average temperature rise. By using it, the influence of the energizing current can be canceled. On the other hand, in a closed tank in which the energizing current does not flow in the high-voltage conductor, the correction can be performed without being affected by the energizing current by using the outside air temperature. As described above, in any case, highly accurate temperature correction can be performed, and gas leakage can be detected early.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 shows an embodiment of a gas leakage monitoring device for a gas insulated switchgear according to the present invention. The high-voltage conductor 2A to the void inside the closed tank 1A to 1C of the gas insulated switchgear.
2C and the opening / closing sections 7A and 7B are electrically insulated from the closed tanks 1A to 1C, and the closed tanks 1A to 1C are formed by convection.
Insulating gases 3A to 3C are sealed at a predetermined pressure to cool the inside of C. In order to detect this gas pressure, gas pressure sensors 4A to 4C are provided in the closed tanks 1A to 1C by using pipes and flanges. Also,
A surface temperature sensor 5 for detecting the outer wall surface temperature is provided on the surface of the outer wall of the closed tank 1C, and an air temperature sensor 6 for detecting the outer air temperature is provided near the gas insulated switchgear. Further, in order to detect the presence / absence of a current flowing through the high voltage conductors 2A to 2C, auxiliary contacts 8A, 8 for outputting the open / closed state of the open / close parts 7A, 7B.
B is provided. Furthermore, a plurality of gas pressure sensors 4A-4C
Each of the gas pressures detected in step 1, the outer wall surface temperature detected by the surface temperature sensor 5, and the output signal of the outside air temperature detected by the temperature sensor 6 and the signals of the auxiliary contacts 8A, 8B are taken in, and the auxiliary contact 8A or 8B is opened and closed. If the closed state of the section 7A or 7B, that is, the state in which the energized current is flowing, the outer wall surface temperature is regarded as the gas average temperature, and if the open circuit of the opening / closing section 7A or 7B, that is, the state in which the energized current is not flowing, indicates the outside air. The temperature is regarded as the gas average temperature, and the temperature correction means 9 for calculating the gas pressure conversion value at the reference temperature is provided, and the calculated gas pressure conversion value is fetched and compared with a preset judgment value to leak gas. A gas leak determination means 10 for determining the presence or absence of the above is provided.

The gas pressure sensors 4A to 4C are semiconductor strain gauges and pressure gauges with potentiometers, and the surface temperature sensor 5 and the temperature sensor 6 are platinum resistance temperature detectors, thermocouples, temperature correction means 9, and gas leak determination. For the means 10, a microprocessor, 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 1C changes depending on the gas average temperature as shown by the curve X in FIG. 2, the rated enclosed gas pressure is normally 0 in FIG. 2, that is, the reference temperature t0.
It is expressed by the gas pressure P0 at. During the actual operation of the equipment, in addition to the change in the outside air temperature, the mean gas temperature changes in a complicated manner under the influence of disturbances such as energizing current, solar radiation and wind and rain, and the gas pressure also changes accordingly. Now, the device corresponds to the state Y in FIG. 2, the gas average temperature t1 and the gas pressure P.
Assuming the case of 1, the gas pressure sensor 4C and the surface temperature sensor 5 detect the pressure P1 and the temperature t1, respectively, and output an electric signal corresponding to these. The temperature correction means 9 can obtain the gas pressure conversion value P2 at the reference temperature t0 shown by the state Z in FIG. 2 by taking in these electric signals and using a predetermined correction formula. When the gas pressure conversion value P2 is smaller than a preset determination value PN, the gas leakage determination means 10 determines that there is a gas leakage, and issues a contact output or lamp abnormality notification.

Here, 11A, 11B, and 11C in FIG. 1 respectively represent the lead terminals of the gas-insulated switchgear,
Operate in coordination with other equipment and power lines. Assuming that the opening / closing part 7A is closed and the opening / closing part 7B is open, the lead terminals 11A and 11C are connected to each other, and a conducting current flows through the high-voltage conductors 2A and 2C, causing internal heat generation such as Joule heat, thereby causing a sealed tank. Insulating gas 3A and 3 inside 1A and 1C
The temperature of C rises, and the gas pressure rises accordingly. At this time, as the temperature of the insulating gas 3C rises, the temperature of the outer wall of the closed tank 1C also rises, and the surface temperature of the outer wall almost matches the gas average temperature. Therefore, the surface temperature sensor 5 provided on the surface of the outer wall of the closed tank 1C The average temperature of the insulating gas 3C can be indirectly obtained. Therefore, the gas pressure sensor 4C provided in the closed tank 1C in the temperature correction means 9
By correcting the pressure detected in 1 above with the outer wall surface temperature detected by the surface temperature sensor 5, it is possible to cancel the influence of the energized current and obtain an accurate gas pressure conversion value.

In the case of the closed tank 1A, the insulating gas 3 inside
Although the temperature of A is not detected on the outer wall surface of the tank 1A, the degree of temperature rise due to the amount of the energizing current is the same as that of the closed tank 1C. Therefore, the temperature correction means 9 recognizes that the energizing current is flowing through the auxiliary contact 8A, and corrects the gas pressure detected by the gas pressure sensor 4A with the outer wall surface temperature detected by the outer wall surface temperature sensor 5 of the closed tank 1C. By doing so, it is possible to cancel the influence of the energizing current and obtain an accurate gas pressure conversion value.

In the case of the closed tank 1B, since the opening / closing part 7B is opened and no current is flowing through the high voltage conductor 2B,
The temperature of the insulating gas 3B inside does not rise, and the gas average temperature matches the outside air temperature. Therefore, in the temperature correction means 9, by recognizing that the energizing current is not flowing through the auxiliary contact 8B and correcting the gas pressure detected by the gas pressure sensor 4B with the outside air temperature detected by the temperature sensor 6,
An accurate gas pressure conversion value can be obtained.

Contrary to the above assumption, when the opening / closing portion 7A is open and the opening / closing portion 7B is closed, the energizing current is equal to the high voltage conductors 2B and 2B.
It flows to C. Therefore, in the temperature correction means 9, the pressure detected by the gas pressure sensors 4B and 4C is corrected by the gas average temperature detected by the surface temperature sensor 5, and the gas pressure detected by the gas pressure sensor 4A that is not affected by the energizing current is calculated. By correcting with the outside air temperature detected by the temperature sensor 5,
An accurate gas pressure conversion value can be obtained for any of the closed tanks 1A and 1B.

As mentioned above, the temperature correction means 9
In regard to which of the outer wall surface temperature and the outside air temperature is selected as the temperature at the time of correction, the opening / closing unit 7A,
It is determined as follows with reference to the auxiliary contact that outputs the open / closed state of 7B. That is, in the closed tanks 1A and 1B, the presence / absence of the energizing current is recognized by the state of the opening / closing portions 7A and 7B,
The outside air temperature may be selected in the open state, and the outer wall surface temperature may be selected in the closed state. Since the energization current always flows in the closed tank 1C, the outer wall surface temperature may be always selected.

As described above, the presence / absence of the energizing current is recognized from the open / closed states of the open / close sections 7A and 7B, and either the outer wall surface temperature or the outside air temperature is selected to correct the gas pressure, thereby making it accurate. It is possible to obtain a gas gas converted value. Therefore, the determination value in the gas leakage determination means 10 can be set strictly so that the gas leakage can be detected early.

[0018]

According to the present invention, the gas pressure is corrected by recognizing the presence or absence of an energizing current and selecting either the outer wall surface temperature or the outside air temperature, so that an accurate gas pressure conversion value can be obtained. The gas leak can be detected early.
Further, the number of temperature sensors can be reduced as compared with the conventional one, and the cost of the monitoring device including the amount of data to be processed can be reduced.

In the above-mentioned embodiment, three gas pressure sensors, one surface temperature sensor and one air temperature sensor are used for the three closed tanks, whereas in the prior art, the gas pressure is applied to each of the three closed tanks. I need a sensor and a temperature sensor,
You can save one temperature sensor. When a large number of gas-insulated switchgears are installed at one location, the effect of saving the temperature sensor is remarkable. For example, when 10 gas-insulated switchgears shown in the above-mentioned embodiment are installed, the temperature is reduced by the conventional technique. According to the present invention, the number of sensors is 3 × 10 = 30, whereas the surface temperature sensor provided in any one of the closed tanks and the air temperature sensor in common are 11 in total. Only 19 temperature sensors are needed, and 19 temperature sensors can be saved.

[Brief description of drawings]

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

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

[Explanation of symbols]

 1A to 1C Closed tank 2A to 2C Electrical components 3A to 3C Insulating gas 4A to 4C Gas pressure sensor 5 Surface temperature sensor 6 Air temperature sensor 7A, 7B Opening / closing part 8A, 8B Auxiliary contact 9 for outputting open / closed state 9 Temperature correction means 10 Gas leak determination means 11A to 11C Lead terminal

Claims (1)

[Claims] 1. A gas-insulated switchgear in which a high-voltage conductor having a branched portion and an opening / closing part are housed in a plurality of closed tanks, and an insulating gas is sealed in a gap at a predetermined pressure. A plurality of gas pressure sensors that are provided to detect the pressure of the enclosed insulating gas; a surface temperature sensor that is provided on the surface of any one of the outer walls of the closed tank to detect the outer wall surface temperature; An air temperature sensor provided in the vicinity of the insulating switchgear to detect the outside air temperature, each gas pressure detected by the plurality of gas pressure sensors, and an outer wall surface temperature detected by the surface temperature sensor and the air temperature sensor detected. The output signal of the outside air temperature is taken in, and in the closed tank in which a current is flowing through the high-voltage conductor, the outer wall surface temperature is regarded as the gas average temperature, In the closed tank where no current is flowing to the body, the outside air temperature is regarded as the gas average temperature, and the temperature correction means for calculating the gas pressure conversion value at the reference temperature, and the calculated gas pressure conversion value are set in advance. A gas leak monitoring device for a gas insulated switchgear, comprising: a gas leak judging means for judging whether or not there is a gas leak by comparing with a judgment value set.