JP3049702B2 - Gas leak monitoring device for gas insulated switchgear - Google Patents

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 insulated switchgear for monitoring leakage of insulating gas sealed in a closed tank.

[0002]

2. Description of the Related Art An insulating gas such as sulfur hexafluoride sealed in a gas insulated switchgear has a function of electrically insulating a high-voltage conductor and a switchgear from a closed tank and cooling the inside of the closed tank by convection. Have. Therefore, since the leakage of the insulating gas has a great effect on the performance of the switchgear, it has been conventionally monitored using a gas density switch.

[0003] In recent years, a gas leak monitoring device combining a gas pressure sensor and an air temperature sensor as disclosed in Japanese Patent Application Laid-Open No. 3-222613, and a maximum gas temperature and a maximum gas temperature as disclosed in Japanese Patent Application Laid-Open No. 4-192509 have been disclosed. A gas leak detector that detects gas pressure and load factor has been introduced.

[0004]

SUMMARY OF THE INVENTION Among the above prior arts,
In monitoring using a gas density switch, a gas density switch may be installed at a location corresponding to the average gas temperature, but in practice, the temperature distribution in the closed tank changes complicatedly due to the internal heat generated by the current flow. Therefore, there is a problem in that an error occurs when the determination value of the gas leak is made strict, and a malfunction occurs when the determination value is made loose, and when the determination value is made loose, the detection of the gas leak is delayed. In addition, this method is a method of issuing an alarm only when a predetermined determination value set in advance is reached, and constantly monitors the gas pressure and determines a small gas leak early from the decreasing tendency, It was difficult to systematically perform measures such as investigating gas leaks, repairing and refilling the insulating gas.

[0005] In order to improve the above-mentioned difficulties, a device for constantly detecting the gas pressure value 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 that combines the gas pressure sensor and the air temperature sensor, in order to perform correction using the outside air temperature as a substitute for the gas average temperature, it is assumed that the internal heat generation due to the supplied current is small at the time of the gas leak determination. 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 over time, a complicated method considering the heat capacity of the electric device and the time constant of the temperature change is used. The arithmetic processing is required, and the number of sensors and the amount of data are increased due to the necessity of providing a temperature sensor in each closed tank, so that the monitoring device is expensive.

Accordingly, an object of the present invention is to obtain a gas pressure conversion value at a reference temperature by performing a high-precision temperature correction on each gas pressure detected by a plurality of gas pressure sensors without being affected by an applied current. Another object of the present invention is to provide an inexpensive monitoring device capable of detecting a gas leak at an early stage.

[0007]

According to the present invention , a plurality of hermetic seals are provided.
A high-voltage conductor having a branch portion and a switching unit in the tank
And a gas filled with an insulating gas at a predetermined pressure.
Insulated switchgear, the closed tanks
Each is provided to detect the pressure of the enclosed insulating gas
A plurality of gas pressure sensors and a plurality of the closed tanks;
That is, the high-voltage conductor in which the current flows constantly is stored.
Provided on the surface of any one of the outer walls of the closed tank,
A surface temperature sensor for detecting an outer wall surface temperature;
An air sensor installed near the edge opening and closing device to detect the outside air temperature
A temperature sensor and the plurality of gas pressure sensors.
Outer wall surface detected by each gas pressure and surface temperature sensor
Output of surface temperature and outside air temperature detected by the temperature sensor
A signal is taken, and a current is flowing through the high-voltage conductor.
In the closed tank, the outer wall surface temperature is regarded as the gas average temperature.
And the hermetic tap having no current flowing through the high-voltage conductor.
In the link, the outside air temperature is regarded as the gas average temperature,
Temperature correction method to calculate the gas pressure conversion value in
Set the stage and the calculated gas pressure conversion value in advance.
Gas to determine the presence or absence of gas leakage by comparing with the set judgment value
A leak determining means is provided.

[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 based on the presence or absence of the energizing current. By selecting from the surface temperature or the outside air temperature, the influence of the energizing current can be eliminated. In other words, in a closed tank where a current flows through the high-voltage conductor,
Since the rise in the average gas temperature due to the flowing current raises the wall temperature of the closed tank, the surface temperature sensor provided on the surface of the outer wall can detect the increase in the average gas temperature. By using this, it is possible to cancel the influence of the flowing current. On the other hand, in a closed tank in which no current flows through the high-voltage conductor, the correction can be performed without being affected by the 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]

FIG. 1 shows an embodiment of a gas leak monitoring device for a gas insulated switchgear according to the present invention. The gaps inside the sealed tanks 1A to 1C of the gas insulated switchgear are connected to the high voltage conductors 2A to 2C.
2C and the opening / closing portions 7A, 7B are electrically insulated from the closed tanks 1A-1C, and the closed tanks 1A-1
Insulating gases 3A to 3C are sealed at a predetermined pressure in order to cool the inside of C. In order to detect the gas pressure, gas pressure sensors 4A to 4C are provided in the closed tanks 1A to 1C using pipes and flanges, respectively. Also,
A surface temperature sensor 5 for detecting an outer wall surface temperature is provided on a surface of an outer wall of the closed tank 1C, and an air temperature sensor 6 for detecting an outside air temperature is provided near the gas insulated switchgear. Auxiliary contacts 8A, 8 for outputting the open / closed state of the switching units 7A, 7B in order to detect the presence or absence of a current flowing through the high voltage conductors 2A to 2C.
B is provided. Further, a plurality of gas pressure sensors 4A to 4C
The output signals of the respective gas pressures detected by the above, the outer wall surface temperature detected by the surface temperature sensor 5, the outside air temperature detected by the air temperature sensor 6, and the signals of the auxiliary contacts 8A and 8B are taken in, and the auxiliary contacts 8A or 8B are opened and closed. If it indicates a closed state of the portion 7A or 7B, that is, a state in which the energizing current is flowing, the outer wall surface temperature is regarded as the gas average temperature. Temperature correction means 9 is provided to calculate the gas pressure conversion value at the reference temperature by assuming the temperature as the gas average temperature, take in the calculated gas pressure conversion value, and compare the gas pressure conversion value with a preset judgment value to determine the gas leakage. Gas leak determining means 10 for determining the presence or absence of the gas leak is provided.

The gas pressure sensors 4A to 4C have a semiconductor strain gauge or a pressure gauge with a potentiometer, and the surface temperature sensor 5 or the temperature sensor 6 has a platinum resistance temperature detector or thermocouple, a temperature correcting means 9, a gas leak judging means. As the means 10, a microprocessor, a personal computer, or the like is used. The surface temperature sensor 5 is provided for the closed tanks 1A to 1C.
Of which, the high-density
It is provided on the surface of the outer wall of the closed tank 1C. That is, the surface temperature
The degree sensor 5 houses a high-voltage conductor through which a constant current flows.
It is installed in one of the closed tanks.
In the case of an example, in a general operation mode, the opening / closing units 7A and 7
B is open when one is closed
From the high voltage conductor 2A or the high voltage conductor 2B.
The high-voltage conductors 2A and 2B are
The flow may or may not flow, and the high voltage conductors 2A, 2A
B is not always energized, so it is always energized
In a closed tank 1C containing a high-voltage conductor 2C through which current flows
A surface temperature sensor 5 is provided.

Next, a method of 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 sealed gas pressure is usually the state 0 in FIG. 2, that is, the reference temperature t0.
At the gas pressure P0. During the actual operation of the equipment, the average gas temperature changes in a complicated manner due to the influence of disturbances such as current flow, solar radiation, wind and rain, in addition to changes in the outside air temperature, and the gas pressure also changes accordingly. Now, the apparatus is in the state Y of FIG.
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 thereto. The temperature correction means 9 takes in these electric signals, and can obtain the gas pressure conversion value P2 at the reference temperature t0 indicated by the state Z in FIG. 2 by using a predetermined correction formula. If the gas pressure conversion value P2 is smaller than a predetermined judgment value PN, the gas leak judgment means 10 judges that the gas is leaking, and issues an abnormality report such as contact output or lamp lighting.

Here, reference numerals 11A, 11B and 11C in FIG. 1 denote lead terminals of the gas insulated switchgear, respectively.
Each is operated in conjunction with other equipment or transmission lines. Assuming that the opening / closing section 7A is closed and the opening / closing section 7B is open, a connection is established between the lead terminals 11A and 11C, and an energizing current flows through the high-voltage conductors 2A and 2C, generating internal heat such as Joule heat and causing a closed 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, so that 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 obtained indirectly. Therefore, the gas pressure sensor 4C provided in the closed tank 1C in the temperature correcting means 9
By correcting the pressure detected by the above with the outer wall surface temperature detected by the surface temperature sensor 5, 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 1A, the inner insulating gas 3
Although the temperature of A is not detected on the outer wall surface of the tank 1A, the degree of the temperature rise due to the amount of the supplied current is the same as that of the closed tank 1C. Therefore, the temperature corrector 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 section 7B is opened and no current flows through the high-voltage conductor 2B,
The temperature of the inside insulating gas 3B does not rise, and the average gas temperature matches the outside air temperature. Therefore, the temperature correction means 9 recognizes that no current is flowing through the auxiliary contact 8B, and corrects the gas pressure detected by the gas pressure sensor 4B with the outside air temperature detected by the air temperature sensor 6, thereby
An accurate gas pressure conversion value can be obtained.

Contrary to the above assumption, when the opening / closing section 7A is open and the opening / closing section 7B is closed, the energizing current is applied to the high voltage conductors 2B and 2B.
Flow to C. Accordingly, the temperature correction means 9 corrects the pressures detected by the gas pressure sensors 4B and 4C with the average gas temperature detected by the surface temperature sensor 5, and calculates the gas pressure detected by the gas pressure sensor 4A which is not affected by the current. 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 described above, the temperature correction means 9
In the case of selecting the outer wall surface temperature or the outside air temperature as the temperature at the time of performing the correction, the opening and closing unit 7A,
The following determination is made 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 or absence of the current is recognized based on 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 energized current always flows in the closed tank 1C, the outer wall surface temperature may be selected at all times.

As described above, the presence or absence of an energizing current is recognized based on the open / closed state 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 achieving accurate gas pressure. A gas conversion value can be obtained. Therefore, the determination value in the gas leak determination means 10 is set strictly, and the gas leak can be detected at an early stage.

[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 is obtained. , Gas leakage can be detected early.
In addition, the number of temperature sensors can be reduced as compared with the related art, and the cost of the monitoring device including the amount of data to be processed can be reduced.

In the above-described embodiment, three gas pressure sensors, one surface temperature sensor, and one air temperature sensor are used in three closed tanks, whereas in the prior art, the gas pressure is stored in each of the three closed tanks. Need a sensor and a temperature sensor,
One temperature sensor can be saved. When many gas insulated switchgears are installed in one place, the effect of saving the temperature sensor is remarkable. For example, when 10 gas insulated switchgears shown in the above-described embodiment are installed, the temperature in the conventional technology is reduced. According to the present invention, a total of 11 surface temperature sensors provided in any one of the closed tanks and one common air temperature sensor are required, whereas the total number of sensors required is 3 × 10 = 30. Only 19 temperature sensors are required, and 19 temperature sensors can be saved.

[Brief description of the drawings]

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

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

[Explanation of symbols]

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

Continuation of the front page (56) References JP-A 62-141745 (JP, U) JP-A 1-131141 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01M 3 / 26

Claims (1)

(57) [Claims] A gas-insulated switchgear in which a high-voltage conductor having a branch portion and an opening / closing section 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 provided for detecting the pressure of the sealed insulating gas, and a plurality of closed tanks, before a current is constantly supplied therethrough.
A surface temperature sensor provided on the surface of any one of the outer walls of the closed tank containing the high-voltage conductor to detect an outer wall surface temperature; and a surface temperature sensor provided near the gas insulated switchgear to detect an outside air temperature. An air temperature sensor, and an output signal of each gas pressure detected by the plurality of gas pressure sensors, an outer wall surface temperature detected by the surface temperature sensor, and an outside air temperature detected by the air temperature sensor, and an energizing current is supplied to the high-voltage conductor. In the closed tank that is flowing, the outer wall surface temperature is regarded as the gas average temperature, and in the closed tank where no current flows through the high-voltage conductor, the outside air temperature is regarded as the gas average temperature, and the gas pressure conversion value at the reference temperature is calculated. The calculated temperature correction means and the calculated gas pressure conversion value are compared with a preset judgment value to judge the presence or absence of gas leakage. A gas leak judgment means for, gas leak monitoring device for a gas insulated switchgear having.