JPS6212311A - Gas insulation monitor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a gas insulation monitoring device, and more particularly to an alarm device for monitoring the insulation of a gas insulated switchgear.

[Technical background of the invention and its problems]

In recent years, gas insulated switchgear (hereinafter abbreviated as GIS)
As the use of substations continues to spread rapidly, the scale of each substation is also increasing year by year, coupled with the increase in demand for electricity. In a GIS, a live part is housed inside a grounded metal container, and a highly insulating gas such as SF or gas is sealed.

Gas is divided into each unit for transportation and operational advantages, and as the scale of GIS increases, the gas system that separates each unit becomes more complex.

In GIS, a pressure switch with temperature compensation (hereinafter referred to as a density switch) is usually installed in each gas classification unit as a means of monitoring the insulation performance status of the equipment.
An alarm is issued when the gas pressure in the gas classification unit falls below a certain set value.

However, during inspection, if an operator accidentally or unknowingly lowers the gas pressure in a gas division unit that has energized equipment, the density switch of that gas division unit will automatically lower the gas pressure. Since the alarm circuit is not activated due to the lowering operation, no alarm will be issued for erroneous operation. The insulating performance of normal insulating gas is as shown in FIG. In other words, the breakdown voltage (kV) is plotted on the vertical axis.
If we take the gas pressure (absolute pressure) on the horizontal axis, we get a characteristic curve (2) in accordance with so-called Paschen's law, in which when the gas pressure decreases and the gap length remains the same, the breakdown voltage also decreases. In other words, if the operator continues to lower the gas pressure without noticing even though some equipment is being charged, there is a risk of a ground fault or serious electrical accident.

Moreover, such operational errors are more likely to occur as the scale of the GIS becomes larger and the gas system becomes more complex.

[Purpose of the invention]

The present invention has been made in consideration of the above points, and its purpose is to prevent malfunctions in the event that the gas pressure of the gas division unit containing the device being charged is reduced due to malfunction. An object of the present invention is to provide a gas insulation monitoring device which can prevent electrical accidents such as ground faults by issuing an alarm and informing users of erroneous operation, and which can further improve the reliability of a GIS system.

[Summary of the Invention] In order to achieve the above object, according to the present invention, the output of the density switch and the output of a voltage detection circuit that detects that voltage is applied to the device and outputs the output are connected by an AND circuit. By issuing an alarm only when the gas pressure is below a certain set value and the equipment voltage is above a certain set value, it prevents electrical accidents such as ground faults due to incorrect operation and improves reliability. It is characterized by

[Embodiments of the invention]

An embodiment of the gas insulation monitoring device of the present invention will be described below with reference to FIG. That is, it shows a gas division unit 1 of a gas insulated switchgear (hereinafter abbreviated as GIS again), which has a structure in which power is sent from a bus bar 5 to a line 6.7 via a disconnector 2, 3.4. It has become. Gas divisions are made by insulating spacers 8, 9, and 10 for gas division, and during inspection and installation, gas is supplied or degassed using a normally closed valve 11. Further, the gas density of this gas division unit 1 is controlled by a density switch 13 via a normally open valve 12.

Further, a density switch 20 is connected directly to the grounded tank 14 by piping, and is turned on when the pressure falls below a certain set value at a certain temperature, for example, below 1 kg/cm''g.

Each of the insulating spacers 8, 9, and 10 is provided with a voltage detection circuit using a capacitor partial voltage, and the bus bar 5 is provided with a grounding device 15. Then, the voltage of the bus bar 5 can be detected by the voltage detection circuit. For example, in the figure, as shown by dotted lines on the insulating spacer 8, a voltage detection circuit and a voltage detection device using capacitor voltage division of the embedded electrode 21a! 22
Connect with. This voltage detecting device 22° is turned on and outputs when the voltage of the bus 5 is above a certain set value, for example above the operating voltage of 172°.

Then, the output of the density switch 20 and the output of the voltage detection device 22 are connected by an AND circuit 23, and the output is taken out as the output of the gas insulation monitoring device 24 surrounded by a dotted line.

The effects of this configuration of the present invention will be described. Considering the case of inspecting the disconnector 4, in the inspection work, the normally open valve 12 is first closed to disconnect the alarm of the density switch 13, and the normally closed valve 11 is opened to begin venting the gas. It is assumed that the new circuit devices 2, 3.4 are in an open state and the grounding device 15 is in a closed state, and in the unlikely event that the bus bar 5 is not disconnected from the grid and is being charged.

In such conditions, the GIS typically connects the ground link 14
Since each device is housed inside the battery, it is difficult to ground each device individually, and it is also difficult to confirm whether the device is being charged or not just by looking at it from the outside. The operator does not realize that the bus bar 5 is being charged, and releases gas from the valve 11 to begin lowering the gas pressure in the gas division unit 1. However, if the gas pressure is below a certain set value, for example 1 kg/cm
When the voltage drops below ``g, the density switch 20 turns on, and the voltage detection device 22 detects that the bus 5 is not disconnected from the grid.
Since it is charged, it is in the on state, and AND circuit 2
3, due to the AND condition, the output of the gas insulation monitoring device 24 is turned on and an alarm is issued.The operator notices this alarm and stops the first operation, thereby preventing the occurrence of electrical accidents such as ground faults.

Also, even if the bus 5 is disconnected from the grid and there is no voltage, the voltage detection device can be used! ! Since the output of the gas insulation monitoring device 22 is off, even if the density switch 20 is on, the output of the gas insulation monitoring device 24 is off and no alarm is issued. Therefore, the work can be continued and the predetermined work can be completed. .

Next, another embodiment of the present invention will be described with reference to FIG.

The same parts and parts having the same functions as those in FIG. 1 are given the same reference numerals. A pressure measuring device 1130 and a temperature measuring device 31 for measuring the gas pressure in each gas classification unit 1 are installed in place of the density switch, and a voltage detecting device 32 of the circuit is installed in place of the voltage detecting device, and the outputs of each are connected to a computer device, that is, a calculation device. The device 33 can diagnose the insulation state of the equipment and provide the output of the gas insulation monitoring device M24. In this way, the insulation state of the equipment can be determined under all gas pressure and temperature conditions, and more detailed monitoring becomes possible.

Further, the voltage measuring device 32 described above is a Pockels element 32a.
Measure the voltage by. This Pockels element 32a is an element having the Pockels effect, in which when light is applied to this element via an optical fiber, the polarized light emitted changes depending on the strength of the electric field in which this element is placed. Changes in the electric field can be measured from the outside using the Pockels element 32a, and changes in voltage can be observed.

In this way, the gas insulation monitoring device 24 does not require operations such as disconnecting the alarm circuit like the conventional density switch 13 when performing predetermined inspection work, so the gas insulation monitoring device 24 can be operated manually. The gas insulation monitoring device 24 can be kept in operation at all times without being artificially affected.

Further, the output of this gas insulation monitoring device [24] can be used as an alarm output for work in the substation by connecting all the outputs of each monitoring device in the substation with an OR circuit.

〔Effect of the invention〕

There is no need to disconnect the gas insulation monitoring device from the circuit, and even if an operator accidentally operates a valve, etc., an appropriate alarm can be issued, preventing serious electrical accidents caused by incorrect operation, and GIS It is possible to provide a gas insulation monitoring device that improves reliability as a system.

[Brief explanation of the drawing]

FIG. 1 is a system diagram of the gas insulation monitoring device of the present invention. FIG. 2 is a system diagram of another embodiment of the present invention. FIG. 3 is a diagram showing the relationship between dielectric breakdown voltage and gas pressure. 1... Gas division unit, 2.3.4... Disconnector. 5... bus line, 6,7... line. 8.9.10...Insulating spacer for gas division, 11...
·valve. 12... Normally open valve, 13, 20... Density switch. 14...Grounding tank, 15...Grounding device. 21a...Embedded electrode, 22.32...Voltage detection device. 23...AND circuit, 24...Gas insulation monitoring device,
30...Pressure measuring device, 31...Temperature measuring device, 3
2a...Pockels element, 33... Arithmetic device.

Claims (5)

[Claims] (1) When the insulating gas of a gas insulated switchgear, which is a gas insulated device formed by storing a live part in a grounded tank and filling an insulating gas in this grounded tank, falls below a certain set value. A gas insulated device that connects the output circuit of a pressure switch with temperature compensation that outputs a signal and the output of a voltage detection device that outputs a signal if the voltage of the gas insulated equipment exceeds a certain set value through an AND circuit. Monitoring equipment. (2) The gas insulation monitoring device according to claim 1, wherein the voltage detection device detects a partial voltage of an embedded electrode embedded in an insulating spacer. (3) The gas insulation monitoring device according to claim 1, wherein the voltage detection device detects the voltage using a Pockels element that measures changes in the electric field inside the grounded container. (4) The gas insulation monitoring device according to claim 1, wherein the arithmetic unit is used in place of the AND circuit. (5) A gas insulation monitoring device according to claim 1, wherein a pressure measuring device that measures and outputs gas pressure and a temperature measuring device that measures and outputs temperature are used in place of a temperature compensated pressure switch. .