JP2006311756A - Slow leak detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a slow leak detector which detects a slow leak of gas filled in gas-insulated electrical equipment without being affected by an external environment and a structure in the gas-insulated electrical equipment, and in distinction from the slow leak from an abnormality caused by local heating. <P>SOLUTION: In the slow leak detector, long tanks 1a are connected through spacers 1b, gas divisions are formed by each of the long tanks 1a and the spacers 1b, pressure vessels with SF<SB>6</SB>filled in each gas division are attached to the detector, and the slow leak of the SF<SB>6</SB>is detected by measuring a change in pressure of the SF<SB>6</SB>in the pressure vessels. Gas pressure sensors 3a, 3b are connected to monitor zones for each gas division, and a gas pressure sensor 3c is connected to the monitor zone where two gas divisions are continuously connected by piping 2. A signal processor 4 obtains a finite difference of the change in pressure between the gas pressure sensors 3a, 3b, 3c at the three monitor zones continuously connected, and judges existence or nonexistence of the slow leak from a change of the finite difference. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to an apparatus for detecting leakage of gas (SF ₆ ) enclosed in gas-insulated electrical equipment such as GIS (Gas Insulated Switchgear), and more particularly to an apparatus capable of detecting a slow leak. .

As a method of detecting gas leakage of SF ₆ enclosed in GIS or the like, there is a method of detecting that the gas pressure has been reduced to a certain control value by a gas density switch.

In the method using the gas density switch, SF ₆ is detected after considerable leakage. However, the atmospheric release of SF ₆ encapsulated in GIS or the like has an adverse effect on global warming, so it is necessary to minimize the amount released into the atmosphere, and a slow leak that is a minute leak Is required to be detected.

  As a method for detecting a gas leak, there is a method for detecting a pressure fluctuation by a pressure sensor. The gas pressure value varies greatly depending on the environmental temperature of the gas atmosphere. Therefore, for example, in order to measure the fluctuation of the gas pressure at the divided measurement site in the metal container, a pipe is connected to the measurement site, and a gas pressure sensor and a temperature sensor are provided at the same location of the pipe. The temperature correction of the measured gas pressure is performed by an arithmetic processing system (for example, refer to Patent Document 1).

  In addition, when a relatively gradual rise in temperature occurs due to a local abnormality inside the gas-insulated electrical equipment, a pressure sensor is provided in each of the first compartment and the second compartment to detect the temperature rise. A monitoring device is disclosed that obtains the difference between the pressure changes of the first compartment and the second compartment, and outputs an abnormal signal when the difference exceeds a certain reference value (for example, Patent Documents). 2).

Japanese Patent Laid-Open No. 8-247887 (page 5, FIG. 1, FIG. 2) Japanese Patent Laid-Open No. 2-7830 (Page 2, FIGS. 1 and 2)

  However, the tank capacity of GIS etc. is a huge scale of several hundred liters to several thousand liters, and the shape varies depending on the divided measurement sites, and there are also complex measurement sites, and it is installed outdoors. In the GIS, the gas temperature inside the tank does not become constant due to the influence of weather such as sunshine, and it is difficult to accurately correct the gas pressure by the temperature correction method, and it is difficult to detect the slow leak. is there.

  Another problem is that the characteristics of the arithmetic processing system change over a long period of time.

  Further, when there is a change in the pressure difference in the method for obtaining the pressure difference between the two compartments, there is a problem that it cannot be determined whether the pressure change is due to local heating or due to a slow leak.

  The present invention has been made in order to solve the above-described problems. The slow leak of gas sealed in a gas-insulated electrical device such as GIS is reduced to the external environment and the structure in the gas-insulated electrical device. It is an object of the present invention to provide a slow leak detection device that can be detected without being influenced and distinguished from an abnormality caused by local heating.

The slow leak detection device according to the present invention is provided in a pressure vessel in which a plurality of tanks are connected via spacers, and gas sections having a sealed structure are formed by the tanks and the spacers, and each gas section is filled with an insulating gas. In the slow leak detection device for detecting the slow leak of the insulating gas from the pressure vessel by measuring the pressure change of the insulating gas in the pressure vessel,
A sealed area for each gas section or a sealed area in which a plurality of the gas sections are in communication is set as a monitoring section for measuring a pressure change of the insulating gas,
Find the difference in pressure change between three or more connected monitoring zones,
The presence or absence of a slow leak of the insulating gas is determined from the change in the difference obtained.

  The slow leak detection apparatus according to the present invention can be detected without being affected by the external environment and the structure in the gas-insulated electric apparatus and distinguished from an abnormality caused by local heating.

Embodiment 1 FIG.
FIG. 1 is a configuration diagram showing a first embodiment of a slow leak detection apparatus according to the present invention, and shows a GIS as an example.
As shown in FIG. 1, the GIS 1 has a configuration in which a plurality of long tanks 1a are connected. Adjacent tanks are separated by a spacer 1b made of an insulating material to form respective gas sections. Each gas section is filled with an insulating gas such as SF _{6 at a} predetermined pressure. The gas pressure monitoring section is a gas section unit, and when the gas pressure sensors 3a and 3b are connected via the pipe 2 for each gas section unit, the gas pressure monitoring section is a plurality of gas sections and a plurality of monitoring sections are piped. 2 and the gas pressure sensor 3c may be connected to the connected pipe 2 in some cases. Signals from the gas pressure sensors 3a, 3b, and 3c are output to the signal processing device 4 and processed by the signal processing device 4.

FIG. 2 is a diagram illustrating an example of the configuration of the signal processing device 4.
The signals of the gas pressure sensors 3a, 3b, 3c output to the signal processing device 4 are converted into digital signals by the A / D converter 6, respectively, and the converted digital signals are input to the calculator 7, where 7, the difference between the digital signals obtained by converting the signals of the gas pressure sensors 3a, 3b, 3c is calculated, and a determination process is performed.

  FIG. 3 shows an example of the result of the signal processing device 4 calculating the sensor output A of the gas pressure sensor 3a, the sensor output B of the gas pressure sensor 3b, the sensor output C of the gas pressure sensor 3c, and the difference between these sensor outputs. FIG. In this example, the initial values (filled gas pressure) of the sensor output A, the sensor output B, and the sensor output C are the same.

  Here, the monitoring section measured by the gas pressure sensor 3a and the monitoring section measured by the gas pressure sensor 3b are adjacent to each other, and the monitoring section measured by the gas pressure sensor 3b and the monitoring section measured by the gas pressure sensor 3c are Since three adjacent monitoring sections are continuously connected, and each monitoring section can be regarded as having almost the same external environment, changes in sensor output A, sensor output B, and sensor output C are caused by this change. If it is only due to the external environment and there is no pressure change due to gas leakage, sensor output A, sensor output B and sensor output C show the same change, and the difference shows a value of zero. On the contrary, as shown in FIG. 3, when the sensor output B decreases and shows a change different from the sensor outputs A and C, and a difference occurs, an abnormality occurs in the monitoring section measured by the gas pressure sensor 3b, and the gas It can be determined that a leak has occurred.

  FIG. 4 is a diagram illustrating an example of a normal case and an abnormal case in the result of the determination processing by the signal processing device 4. FIG. 4A shows that sensor output A, sensor output B, and sensor output C tend to decrease, but show the same change tendency, and the difference between sensor output A, sensor output B, and sensor output C is 0. It is determined that no gas leak occurred. FIG. 4B shows that the sensor output A and the sensor output C have the same decreasing tendency, the sensor output B has a decreasing tendency larger than the decreasing tendency of the sensor output A and the sensor output C, The difference from the sensor output B decreases (-value increases), it is determined that an abnormality has occurred in the monitoring section measured by the gas pressure sensor 3b, and gas leakage has occurred. FIG. 4C shows that sensor output A and sensor output C tend to increase while sensor output B tends to decrease, and the difference between sensor output A and sensor output C and sensor output B decreases. Then, it is determined that an abnormality has occurred in the monitoring section measured by the gas pressure sensor 3b and gas leakage has occurred. Although not shown, when the difference indicates an increase, it is determined that an abnormality accompanied by a heat generation factor such as local heating has occurred.

  As described above, according to the slow leak detection device of the first embodiment, the slow leak sealed in the gas insulated electrical equipment such as GIS is affected by the external environment and the structure in the gas insulated electrical equipment. In addition, it is possible to detect in which monitoring section the slow leak is generated as distinguished from the abnormality due to the local heating.

  In the first embodiment, an example in which the pressure change in the three connected monitoring sections is detected has been described. However, when the external environment of the three or more connected monitoring sections is determined to be substantially the same, three pressures are detected. You may make it detect the pressure change of the above monitoring divisions.

Embodiment 2. FIG.
FIG. 5 is a block diagram showing Embodiment 2 of the slow leak detection apparatus according to the present invention, and shows GIS as an example.
In the second embodiment, a simple memory 15 for accumulating data of the gas pressure sensor 3 is provided. Note that FIG. 5 shows an example in which the simple memory 15 is connected to the gas pressure sensor 3 connected to one monitoring section. However, in practice, the gas pressure sensor connected to each of the plurality of monitoring sections is simplified. Memory is connected. One simple memory may be connected to a plurality of gas pressure sensors.

  Since the purpose of the slow leak detection is to see a change of about 1% per year, for example, the gas pressure measurement data of one point per day is recorded in the simple memory 15 and the simple memory 15 is read once a year. Data may be collected and a slow leak determination process may be performed based on the data.

  The collected simple memory 15 data is read by a personal computer or the like, and, for example, is processed by a general-purpose application, or the data is graphed to compare the pressure values of three or more connected monitoring sections, thereby causing a slow leak The determination process can be performed. By performing such data collection and slow leak determination processing off-line, the system configuration of the slow leak detection can be simplified and the cost can be reduced.

Embodiment 3 FIG.
FIG. 6 is a block diagram showing Embodiment 3 of the slow leak detection apparatus according to the present invention.
In the first embodiment (see FIGS. 1 and 2), the sensor outputs A, B, and C of the gas pressure sensors 3a, 3b, and 3c are compared with each other in the S / W manner by the computing unit 7. In the third embodiment, as shown in FIG. 6, the differential amplifier 5 is used to compare the sensor outputs A, B, and C of the gas pressure sensors 3a, 3b, and 3c.

  The signals of the gas pressure sensors 3a, 3b and 3c are input to the differential amplifier 5, and the difference between the signals of the gas pressure sensors 3a, 3b and 3c is output to the A / D converter 6, and the A / D converter 6 It is converted into a digital signal, and a determination process is performed by the arithmetic unit 7 based on the digital signal from the A / D converter 6. Since the digital signal of the A / D converter 6 has already been obtained by the differential amplifier 5 as the differential pressure between the gas pressure sensors 3a, 3b and 3c, does the arithmetic unit 7 tend to increase the differential pressure? The presence / absence of abnormality can be confirmed by a simple determination of whether it is decreasing or not, and the arithmetic program of the arithmetic unit 7 can be simplified.

  As shown in FIG. 6, when A and B increase and C does not change, there is an abnormality in heat generation in the monitoring section of the gas pressure sensor 3a, A and B decrease, and C does not change. If there is a slow leak in the monitoring section of the gas pressure sensor 3a, a and u increase, and if i does not change, there is a slow leak in the monitoring section of the gas pressure sensor 3b, and a and u decrease. When a is not changing, there is an abnormality in heat generation in the section of the gas pressure sensor 3b, and when a is decreasing, c increases, and when a is not changing, there is an abnormality in the generation of heat in the monitoring section of the gas pressure sensor 3c. Yes, it is determined that there is a slow leak in the section of the gas pressure sensor 3c when A increases, C decreases, and A does not change.

  According to the third embodiment, the differential amplifier 5 obtains the differential pressure between the gas pressure sensors 3a, 3b and 3c, whereby the calculation program of the calculator 7 can be simplified and the cost of the apparatus can be reduced. can do.

Embodiment 4 FIG.
FIG. 7 is a block diagram showing Embodiment 4 of the slow leak detection apparatus according to the present invention.
In the third embodiment, the differential pressure between the gas pressure sensors in each monitoring section is obtained by a differential amplifier. However, in the fourth embodiment, as shown in FIG. It is determined by the differential pressure sensor 3d.

  By adopting a differential sensor that has a narrow detection range and can handle minute changes as the differential pressure sensor 3d, the pressure change can be captured with higher sensitivity.

  As shown in the block diagram of FIG. 8, the differential pressure between each gas section is output to the A / D converter 6 and converted into a digital signal, and is obtained by the computing unit 7 as in the third embodiment. The presence or absence of abnormality can be confirmed by a simple determination of whether the differential pressure is increasing or decreasing.

  According to the fourth embodiment, by calculating the differential pressure between each gas section with the differential pressure sensor, the calculation program of the calculator 7 can be simplified, and the cost of the apparatus can be reduced.

  Further, since the differential amplifier is not necessary, the slow leak detection device is simplified and the cost is reduced.

Embodiment 5. FIG.
FIG. 9 is a block diagram showing Embodiment 5 of the slow leak detection apparatus according to the present invention.
In the fifth embodiment, a reference signal generator 9 that outputs a signal of a predetermined value is provided, and the gas pressure sensor 3 and the reference signal generator 9 are switched by a switch 11 in accordance with an instruction from the controller 10 to generate a reference signal. Predetermined predetermined values of the calculator 9 are input to the A / D converter 6, the characteristic values of the A / D converter 6 are read into the calculator 7, and the initial characteristics held in the calculator 7 are stored in advance. The characteristic change is read by comparing with the value, and the digital signal converted by the gas pressure sensor 3 is corrected by the characteristic change, and the computing unit 7 performs determination processing based on the corrected digital signal.

  According to the fifth embodiment, it is possible to correct the characteristic change of the arithmetic processing system over a long period of time and perform accurate slow leak determination.

  The configurations of the reference signal generator 9, the switch 11 and the controller 10 in the fifth embodiment can be applied to the third and fourth embodiments.

The slow leak detection apparatus according to the present invention can be effectively used as an apparatus for detecting a slow leak of gas (SF ₆ ) sealed in a gas insulated insulated electric device such as GIS.

It is a block diagram which shows Embodiment 1 of the slow leak detection apparatus which concerns on this invention. It is a block diagram which shows an example of a structure of a signal processing apparatus. It is a figure which shows an example of the result of having calculated the sensor output A of the gas pressure sensor 3a, the sensor output B of the gas pressure sensor 3b, the sensor output C of the gas pressure sensor 3c, and the difference of these sensor outputs with the signal processing apparatus 4. . It is a figure which shows the example in the normal case in the result of the judgment process by the signal processing apparatus 4, and an abnormal case. It is a block diagram which shows Embodiment 2 of the slow leak detection apparatus which concerns on this invention. It is a block diagram which shows Embodiment 3 of the slow leak detection apparatus which concerns on this invention. It is a block diagram which shows Embodiment 4 of the slow leak detection apparatus which concerns on this invention. FIG. 10 is a block diagram illustrating a signal processing device in a fourth embodiment. It is a block diagram which shows Embodiment 5 of the slow leak detection apparatus which concerns on this invention.

Explanation of symbols

1 GIS, 1a long tank, 1b spacer, 2 piping,
3, 3a, 3b, 3c gas pressure sensor, 3d differential pressure sensor, 4 signal processing device,
5 differential amplifier, 6 A / D converter, 7 arithmetic unit, 9 reference signal generator,
10 controller, 11 switcher.

Claims (6)

A plurality of tanks are connected via spacers, and each tank and the spacer form a gas section having a sealed structure, and each gas section is provided in a pressure vessel in which an insulating gas is sealed, and the insulating gas in the pressure vessel is provided. In the slow leak detection device that detects the slow leak of the insulating gas from the pressure vessel by measuring the pressure change of
A sealed area for each gas section or a sealed area in which a plurality of the gas sections are in communication is set as a monitoring section for measuring a pressure change of the insulating gas,
Find the difference in pressure change between three or more connected monitoring zones,
Judging whether there is a slow leak of the insulating gas from the change in the obtained difference,
A slow leak detection device characterized by that. A gas pressure sensor for measuring a pressure change in each of the monitoring sections;
An A / D converter that converts each signal measured by the gas pressure sensor into a digital signal and outputs the digital signal;
An arithmetic unit that calculates a difference between digital signals output from the A / D converter and determines the presence or absence of a slow leak based on the calculated difference;
The slow leak detection apparatus according to claim 1, further comprising: A gas pressure sensor for measuring a pressure change in each of the monitoring sections;
A simple memory for storing the pressure change measured by the gas pressure sensor;
The slow leak detection apparatus according to claim 1, further comprising: A gas pressure sensor for measuring a pressure change in each of the monitoring sections;
A differential amplifier that outputs a difference between the pressure changes measured by the gas pressure sensor;
An A / D converter that converts each difference output from the differential amplifier into a digital signal and outputs the digital signal;
An arithmetic unit that determines the presence or absence of a slow leak based on the digital signal output by the A / D converter;
The slow leak detection apparatus according to claim 1, further comprising: A differential pressure gauge that measures and outputs the differential pressure between the monitoring sections; and
An A / D converter that converts each output of the differential pressure gauge into a digital signal and outputs the digital signal;
An arithmetic unit that determines the presence or absence of a slow leak based on the digital signal output by the A / D converter;
The slow leak detection apparatus according to claim 1, further comprising: A reference signal generator for outputting a signal of a predetermined value;
A switch for switching the measured value of the gas pressure sensor and the output of the reference signal generator and inputting the output of the reference signal generator to the A / D converter;
A controller for giving a switching command to the switch and for inputting a characteristic value of the A / D converter when the output of the reference signal generator is input to the A / D converter to the calculator. Prepared,
The arithmetic unit has an initial characteristic value of the A / D converter,
The arithmetic unit compares the initial characteristic value with the characteristic value of the A / D converter input from the controller, and corrects the digital signal output from the A / D converter. The slow leak detection device according to claim 2, 4, or 5.

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