JPH05126773A - Method and apparatus for monitoring moisture in gas insulating apparatus - Google Patents

Abstract

PURPOSE:To detect the rise-up of the dew point of insulating gas in a gas insulating apparatus, i.e., the rise-up of the concentration of moisture automatically at an early stage. CONSTITUTION:A dew-condensation sensor 5, wherein surface temperature is kept at a constant temperature lower than 0 deg.C and which outputs a signal 7S when the dew is condensed at the surface, is provided. A display part 9, which displays the presence or absence of the output signal 7S of the dew condensation sensor 5, is provided. The dew condensation sensor 5 is arranged in a container 3 for containing SF6 gas 1. The rise-up of the concentration of the moisture in insulating gas is detected with the presence or absence of the output signal from the dew condensation sensor 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and a device for detecting an increase in the moisture content in gas of a gas insulated switchgear in which a main body of an electric device is housed in a container together with SF ₆ gas.

[0002]

2. Description of the Related Art In electrical equipment in which SF ₆ gas is sealed, it is important to keep the moisture concentration in SF ₆ gas below a certain value. That is, the dew point temperature in SF ₆ gas
The (condensation temperature of water in the SF ₆ gas) increases as the water concentration increases. When the temperature of the SF ₆ gas becomes lower than the dew point, moisture in the SF ₆ gas may condense and adhere to the surface of the insulator of the electric device body to deteriorate the insulation performance. on the other hand,
It is known that if the dew point is lower than 0 ° C, even if the temperature of the SF ₆ gas falls below the dew point, the condensed water immediately freezes and cannot exist as a liquid, so that it does not affect the insulation performance. .. Therefore, in the SF ₆ gas insulation device, consideration is given to maintaining the dew point at a temperature slightly lower than 0 ° C., for example, −10 ° C. or lower.

Conventionally, in order to manage the dew point of the SF ₆ gas, a SF ₆ gas in the electrical equipment container was measured periodically sampled and its dew point by a commercially available hygrometers. SF
_{If the 6} gas has a high dew point, the water adsorbent in the container has been replaced, or the gas in the container has been replaced with dry SF ₆ gas. As a commercially available dew point meter, for example, there is a type that slowly lowers the temperature of the taken-in gas and obtains the temperature of the gas when the dew condensation is visually observed on the surface of the built-in mirror.

[0004]

However, the conventional moisture monitoring method as described above has a problem in that it is not possible to automatically detect an increase in dew point due to an increase in moisture concentration. That is, it is necessary to manually sample SF ₆ gas, which requires a great deal of labor. In addition, some gas insulation devices are gas-separated into a plurality of containers, and it has been complicated to find out all the dew points of each gas classification. Further, since it is impossible to constantly monitor, when the water concentration in the electric equipment suddenly rises, the dehydration treatment of SF ₆ gas may be delayed and an insulation accident may occur.

An object of the present invention is to provide a method for automatically and early detecting an increase in the dew point of an insulating gas, that is, an increase in the water concentration, and an apparatus therefor.

[0006]

In order to achieve the above object, according to the method of the present invention, the moisture in the insulating gas in the container of the gas-insulated device in which the electric device body is housed in the container together with the insulating gas. A method for monitoring the concentration, wherein a dew condensation sensor that outputs a signal when dew condensation is formed on the surface of the container, the surface is kept at a constant temperature lower than 0 ° C. The presence or absence of water will be used to detect an increase in water concentration.

Further, the apparatus for carrying out the method of the present invention is an apparatus for monitoring the moisture concentration in the insulating gas in the container of the gas insulation device in which the main body of the electric device is housed in the container together with the insulating gas. Is kept at a constant temperature lower than 0 ° C., and includes a dew condensation sensor that outputs a signal when the surface of the dew condensation occurs, and a display unit that displays the presence or absence of an output signal of the dew condensation sensor. Be placed in

[0008]

According to the method of the present invention, the dew condensation sensor that outputs a signal when dew condensation occurs on the surface is placed in the container containing the insulating gas, and the surface is kept at a constant temperature lower than 0.degree. The rise in water concentration is detected by the presence or absence of the output signal of the dew condensation sensor. If the dew point of the SF ₆ gas is lower than the surface temperature of the dew condensation sensor, dew condensation does not occur, so the dew condensation sensor does not output a signal. When the dew point of the SF ₆ gas becomes higher than the surface temperature of the dew condensation sensor, dew condensation occurs on the sensor surface and the dew condensation sensor outputs a signal, so that the rise of the dew point is automatically and instantaneously detected.

[0009]

EXAMPLES The present invention will be described below based on examples.
FIG. 1 is a cross-sectional view showing the structure of a moisture monitoring device for gas-insulated equipment for carrying out the method of the present invention. SF ₆ gas 1
In addition, the electric device body 2 is housed in the container 3. A dew condensation sensor 5 having a constant temperature device 4 is arranged in the container 3,
It is attached to the inner wall of the container 3 via a support (not shown). Power supply unit 6 of constant temperature device 4 and dew condensation sensor 5
The control unit 7 for operating the is connected to the constant temperature device 4 and the dew condensation sensor 5 via the airtight terminal 8. The display unit 9 receives the output signal 7S from the control unit 7, and outputs the relay contacts, lights the indicator lamp, and issues an alarm.

Although various dew condensation sensors 5 are commercially available, for example, there is one in which the resistance value of the surface of the reaction film changes rapidly due to dew condensation. The control unit 7 constantly measures the resistance value of the dew condensation sensor 5 and outputs a signal to the display unit 9 when the resistance value suddenly increases. Constant temperature device 4 for keeping the surface temperature of the dew condensation sensor 5 at a constant value lower than 0 ° C.
For example, the one using a Peltier element is compact. In the apparatus of FIG. 1, when the moisture content of the SF ₆ gas 1 increases, the dew condensation sensor 5 automatically detects it, and the display unit 9 instantly displays that the moisture concentration of the SF ₆ gas 1 exceeds a predetermined value.

[0011]

As described above, according to the present invention, the dew condensation sensor that outputs a signal when the surface is dewed is placed in a container containing an insulating gas and the surface is kept at a constant temperature lower than 0 ° C. , The rise of the water concentration is detected by the presence or absence of the output signal of the dew condensation sensor. With this method, SF ₆
The rise in the dew point of the gas is automatically and instantaneously detected, and the maintenance of the water concentration can be saved. Further, since the automatic detection is possible, the water concentration of each container can be easily monitored even if there are a plurality of gas divisions of the device. Furthermore, since the moisture concentration can be detected early, it is possible to eliminate the insulation accident due to the internal dew condensation of the gas insulation device.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing the configuration of a moisture monitoring device for gas-insulated equipment according to an embodiment of the present invention.

[Explanation of symbols]

1 SF ₆ gas 2 electric device main body 3 container 4 thermostatic device 5 condensation sensor 6 power supply section 7 control section 7S output signal 8 airtight terminal 9 display section

Claims (2)

[Claims] 1. A method for monitoring the moisture concentration in an insulating gas in a container of a gas insulation device in which a main body of an electric device is housed in a container together with an insulating gas, the dew condensation sensor outputting a signal when dew condensation occurs on the surface. Is placed in the container, the surface thereof is kept at a constant temperature lower than 0 ° C., and an increase in water concentration is detected by the presence or absence of an output signal of the dew condensation sensor. .. 2. A device for monitoring a moisture concentration in an insulating gas in a container of a gas insulation device in which a main body of an electric device is housed in a container together with an insulating gas, the surface temperature being maintained at a constant temperature lower than 0 ° C. And a dew sensor for outputting a signal when dew condensation occurs on the surface, and a display section for displaying the presence or absence of an output signal of the dew sensor, wherein the dew sensor is arranged in the container. Moisture monitoring device for insulation equipment.