JPH02197211A - Gas pressure abnormality detection device for compressed-gas-insulated equipment - Google Patents

Abstract

PURPOSE:To facilitate the installation of a device to a compressed-gas-insulated equipment by finding a differential pressure between the gas pressure in a standard gas container provided so as to be equal to the insulated gas temperature of the gas-insulated equipment with a pressure sensor. CONSTITUTION:The compressed gas in a compressed-gas-insulated equipment 4 is confined into the 1st container 1. The gas is filled up until the gas pressure becomes the same as the gas pressure in the 2nd container 18. Since the gas- insulated equipment 4 is set to the spot so that the gas temperature in the 2nd container 18 will be the same as in the insulated gas, the gas leak will be able to be discovered if the insulated gas pressure in the gas-insulated equipment gets lower than the gas pressure in the 2nd container 18. With a pressure sensor 19 the difference of gas pressure between in the 1st container 1 and the 2nd container 18 is measured and this value is sent to an arithmetic circuit 21. If it is greater than the set value, an alarm signal is issued and sent to a monitoring device, etc.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a gas pressure abnormality detection device for gas insulated equipment that detects gas pressure abnormalities caused by internal flash faults or gas leaks in gas insulated equipment. be.

[Conventional technology]

Figure 2 shows, for example, Mitsubishi Electric Technical Report Vol. 53, No. 10 (197
This is a conventional gas pressure abnormal rise detection device shown in FIG. 10 on page 771 (Year 9). In the figure, (1) is a grounded first container, which is filled with gas pressurized to 2 to 5 atmospheres. (2) is a charging member such as a conductor placed in the first container (1), and (3) is an insulator that supports the charging member (2). In addition, (1) to (3) are gas insulated equipment (4)
It consists of (6) is a second container directly connected to the first container (1), (6) is a bellows that partitions the second container (5), and (7) is a partition between both containers (1) and (5). It is a small open hole.

Therefore, the second container (5) is also filled with the same gas as the first container (1). (8) is bellows (6)
The switch provided at the tip of the switch (9) is the switch (8)
is connected to a monitoring device (not shown) at its output terminal.

Next, these operations will be explained. Now, if a flashover accident occurs due to an arc as shown by A from the charging member (2) of the gas insulated equipment (4) to the container (1), the pressure of the gas inside the gas insulated equipment (4) It rises shockingly due to expansion due to heat. The pressure reaches the inside of the bellows (6), but the pressure of the gas inside the container (5) increases through the small hole (7), so the ground fault arc continues.
There is almost no change in a short period of time such as 0.1 seconds. Therefore, the difference in gas pressure between them causes the bellows (
6) is extended and the switch (8) is turned on (9), transmitting a signal indicating that abnormal pressure has occurred from the terminal (to) to the monitoring device.

FIG. 3 is shown, for example, on page 63 of Electric Kyodo Research Vol. 42, No. 43 (February 1988), and is a gas pressure detector for detecting gas leaks. In the figure, αQ is a second container filled with the same insulating gas as the first container (1), αυ is a third container communicating with the second container a0, and @ is the first The fourth container communicates with the container (1), and is disposed opposite the third container (b).

The bellows seal the third container αp and the fourth container @, respectively, and are arranged to face each other. Oq is a connecting link connecting both bellows α30→, α
The resistor is a constant resistor provided with terminals (16a) and (16b),
The α force is outputted to the terminal (17a) by sliding the face of the variable resistance αQ by a lever connected to the connecting link αQ.

Next, the operation will be explained. Since the gas in the gas insulated device (4) is sealed in a closed container, if the gas temperature is constant, a gas leak can be determined if the pressure is lowered when measured. However, if the temperature changes, the amount of change must be corrected. In the case of Fig. 3, since the second container αQ is placed at the same temperature as the first container (1), these gas pressures are controlled by the bellows (c)04.
In addition to this, if we look at the movement of the connecting link (c), there is no movement if there is no gas leak. However, when the insulating gas (5) of gas insulated equipment leaks, the bellows α
Overcoming the spring force of 3Q→, the connecting link (G) moves to the right and the 1<-α force rotates, the value of variable resistor 01 changes according to the change in pressure, and the terminals (16a) (16b) ( 17a
), the change is transmitted to the monitoring panel via electric wire, and it is determined that there is a leak.

[Problem to be solved by the invention]

Conventional gas pressure abnormality detection devices are configured as described above, so consideration must be given to securing the mounting area and the arrangement and configuration of gas insulated equipment, as well as the risk of gas leakage and malfunctions caused by improper installation of many of these detectors. There are many mechanical parts, so there is a high risk of trouble occurring due to friction and wear, and it is also necessary to install two types of detectors to detect gas leaks and related accidents.
It was also economically disadvantageous.

This invention was made to solve the above-mentioned problems.It is easy to install on gas insulated equipment, and is economical and can be used with two types of conventional detectors with one sensor. The purpose is to obtain a gas pressure abnormality detection device for gas insulated equipment.

[Means to solve the problem]

A first aspect of the present invention is that a gas pressure abnormality detection device for gas insulated equipment includes a container filled with a standard gas, a pressure sensor that detects a difference between the pressure of the standard gas and the gas pressure of the gas insulated equipment; An arithmetic circuit is provided which generates a full signal when this differential pressure exceeds a certain value. Further, the second invention calculates the difference between the differential pressure at the time of measurement and the differential pressure a certain time ago,
It is composed of an arithmetic circuit that generates a signal when this difference exceeds a certain value.

[Operation] The gas pressure abnormality detection device for gas insulated equipment according to the present invention detects the difference between the gas pressure in the standard gas container, which is set to be equal to the insulating gas temperature of the gas insulated equipment, and the gas pressure in the gas insulated equipment. Since the differential pressure is determined using a pressure sensor, a pressure drop due to gas leakage can be detected even when there is a change in temperature. Furthermore, since the difference between the value at the time of measurement and the value measured a certain time before the time of measurement is obtained for the differential force, it is also possible to detect a sudden increase in gas pressure due to internal flashover.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings.

In Figure 1, (to) is a second container sealed with the same gas as the insulating gas in the first container (1), and is a gas insulated equipment (
It is installed so that the temperature is almost the same as the temperature of the insulating gas (4) in 4), and in the case of this figure, it is installed in the first container (1) of the gas insulated equipment (4). 0 is a pressure sensor that measures the entire differential pressure between the gas pressure in the gas insulated device (4) and the gas pressure in the second container (c). Note that as the pressure sensor, a piezoelectric type, a strain gauge type, or other type having good sensitivity and accuracy can be used. The wire is a delay circuit, which delays the measured value of the pressure sensor 0 for a short period of time, about a minute, and then sends it to the next one. 01
) is an arithmetic circuit that calculates the difference between the measured value directly from the pressure sensor 0 and the measured value a short time ago that came through the delay circuit (e), and outputs a signal when the value exceeds the set value. .

The Q calculation circuits also output a signal when the differential pressure of the insulating gas in the second insulating gas container (to) of the gas insulated equipment (4) exceeds a certain set value.

Next, the operation will be explained.

The insulating gas of the gas insulated equipment (4) is sealed in the first container (1), and is filled until the pressure becomes the same as the gas pressure in the second container (to). The gas pressure is filled to a specified pressure at a specified temperature, for example, 4 kq/df when the gas temperature is 20°C. The temperature of the gas in the second container (G) is the same as that of the insulating gas in the gas insulated equipment (4), so the pressure of the insulating gas in the gas insulated equipment is the same as that in the second container. If the pressure drops below the gas pressure in (c), you will know that a gas leak is currently occurring. The pressure sensor α1 is the first
Since the difference in gas pressure between the container (1) and the second container (g) is measured, this value is sent to the arithmetic circuit 11), and if it becomes larger than the set value, an alarm signal is issued. , sent to monitoring equipment, etc. Note that the measured value of this differential pressure is calculated by the calculation circuit Q.
]) to the monitoring device so that it can be determined that there is a tendency for gas leakage before the gas leakage reaches a set value. Since a decrease in gas pressure due to gas leakage leads to a decrease in insulation performance, the amount of gas used during operation is also one of the items to be careful of when using gas insulated equipment (4).

On the other hand, if some kind of malfunction occurs while power is being applied to the gas insulated equipment (4) and a flash fault occurs internally, the operation will be as follows.

If a flash short circuit occurs internally, the insulating gas of the gas insulated device (4) will undergo an explosive pressure rise due to expansion and chemical changes due to the heat of the arc. That is, the fault current is cut off and the arc is extinguished by the protective relay and the circuit breaker (not shown) in about 0.05 to 0.1 seconds, so that the pressure rises in a short time. At this time, the pressure sensor α sends the measured value directly to the arithmetic circuit.

In addition, the measured value of the pressure sensor 0 is also sent to the delay circuit (A), so the value that passes through this and enters the arithmetic circuit Q is the value before a certain set time, and is a normal value without a flashover accident. It shows the entire pressure difference in the state. Therefore, if there is a difference in the pressure difference between the time of measurement and a certain time before, it is determined that there is an abnormal pressure increase due to flash flash or the like. When this value exceeds a certain value, taking into account errors, a signal is generated from the arithmetic circuit (c).

As described above, in the present invention, two types of abnormal states can be detected with one sensor, but since the calculation methods in the calculation circuits η are different, it is possible to distinguish which abnormality is occurring by using different outputs.

Note that if the internal flash fault is detected by another method (for example, by a current difference using a current transformer), only the first half of the gas leak detection function may be used.

〔Effect of the invention〕

As described above, according to the present invention, the pressure difference between the insulating gas of the gas-insulated equipment and the gas having the same temperature as that is measured by a pressure sensor, and a pressure drop due to gas leakage is detected based on the pressure difference. Alternatively, by calculating the difference between the value measured at the time of measurement and the value measured a short time before that time, it is possible to detect pressure increases due to flash faults inside gas-insulated equipment, which can be handled with a single sensor. This has the effect of making it easy to attach to gas insulated equipment, eliminating problems in arrangement, and providing a highly reliable and economical device free from mechanical troubles such as friction and wear.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a gas pressure abnormality detection device for gas insulated equipment according to one embodiment of the present invention, and FIG. 2 is a configuration diagram of an example of a conventional gas pressure abnormality detection device for detecting internal flash faults. FIG. 3 is a configuration diagram of a conventional gas pressure abnormality detection device for detecting gas leakage. In the figure, (1) is the first container, (4)
(G) is a second container, (10 is a pressure sensor, (E) is a delay circuit, and Q◇ is an arithmetic circuit. In each figure, the same reference numerals indicate the same or equivalent parts. .

Claims (2)

[Claims] (1) In a gas pressure abnormality detection device for gas insulated equipment that detects an abnormality in gas pressure in a first container filled with an insulating gas, a second container having a predetermined volume and filled with the above insulating gas is used. A gas insulated device in which a container is placed near the first container, a pressure sensor detects the pressure difference between the two containers, and a signal is output from an arithmetic circuit when the pressure difference exceeds a predetermined value. Gas pressure abnormality detection device. (2) In a gas pressure abnormality detection device for gas insulated equipment that detects an abnormality in gas pressure in a first container filled with an insulating gas, a second container having a predetermined volume and filled with the above insulating gas is used. A container is placed near the first container, the detected value of the pressure sensor is delayed for a predetermined time by a delay circuit, and the difference between the output of the delay circuit and the output of the pressure sensor is a predetermined value. A gas pressure abnormality detection device for gas insulated equipment that outputs a signal from an arithmetic circuit when the pressure is exceeded.