JPS61262010A - Pressure monitor for gas insulated electric appliance - 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 pressure monitoring device for gas-insulated electrical equipment, and in particular monitors pressure by the dielectric strength of a gas insulating medium in a pipe air bus used in a power generation and substation. Relating to a pressure monitoring device.

[Technical background of the invention and its problems]

Gas-insulated switchgears have been widely used in recent years as switchgears for high-voltage circuits used in power plants.

It houses the bus bar, circuit breaker, disconnector, and other equipment in a grounded metal container, which is highly stable, inert, nonflammable, odorless, and harmless.

The device is filled with SF6 gas, which has a dielectric strength about three times that of air at atmospheric pressure, and is used as a switchgear for high-voltage circuits. A conduit aerial busbar is used to connect this gas-insulated switchgear to a bushing or transformer connected to a power transmission line. This is a device in which a conductor is supported using an insulating spacer inside a tubular container filled with an insulating gas, and the length of the conductor and the tubular container are several tens of meters to several hundreds of watts. The insulating spacer used at this time is usually a post-shaped insulating spacer or a tripod-shaped insulating spacer that does not have gas partitioning performance.

That is, as shown in FIG. 11, a conductor 2 is supported and housed in a tubular container 1 having a predetermined length at intervals of several meters by post-shaped or tripod-shaped insulating spacers 3 that do not separate the gas, and the tubular container 1 is It is constructed by sealing a gas insulating medium such as SF or gas 4 in 1.

In such a conventional pipeline air bus, the tubular container 1
Due to defects such as micro-cracks or malfunctions in the sealing structure, leakage of SF and gas 4 may occur, which may cause a decrease in the dielectric strength of the pipe air bus bar. For this reason, a pressure monitoring device such as a density switch is used, but it is expensive and requires conversion such as temperature correction, which is inconvenient and has problems that should be improved.

[Purpose of the invention]

The present invention has been made in consideration of the above points, and its purpose is to provide an inexpensive gas-insulated electrical system that detects a decrease in dielectric strength and prevents accidents without the need for conversion such as temperature correction. An object of the present invention is to provide an equipment pressure monitoring device.

[Summary of the invention]

In order to achieve this object, according to the present invention, a protruding container is provided so that the pressure is the same as that of a gas insulating medium such as a container of gas-insulated electrical equipment, such as SF, gas, and a floating electrode and a measuring device are placed in the projecting container. A gap and current detection current transformer is housed, and the voltage induced in the floating electrode is constantly applied to the measurement gap, and if there is a drop in the pressure of the gas insulating medium in the container, a discharge is generated in the measurement gap. By detecting the current with a current detection current transformer and monitoring the pressure drop, it is characterized by not requiring conversion such as temperature correction, preventing a decrease in dielectric strength, and being inexpensive.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. The same parts as in FIG. 10 are given the same reference numerals.

The conduit air bus 1 of the gas-insulated electrical equipment is formed as follows. That is, conductors 2 are housed in a tubular container la of a predetermined length, supported by post-shaped or tripod-shaped non-sealed insulating spacers 3 at intervals of several meters, and the inside of this tubular container 1a is A gas insulating medium, such as SF, gas 4 is sealed at a predetermined pressure to form a conduit air bus 1. A pressure monitoring device 10 is provided on the pipe air bus 1.

The pressure monitoring device 10 is airtightly attached with a protruding container 5 which communicates with the side surface of the tubular container 1a and has the same pressure as the SF6 gas 4 inside.

A floating electrode 6 is fixedly supported inside the projecting container 5 by a support member 9 made of an insulating material.

The floating electrode 6 is located at the opening of the protruding container 5 and is arranged to face the conductor 2.

A measurement gap portion 7 is connected in series to this floating electrode 6 between the ground and ground. This measurement gap portion 7 includes a gap electrode 7a attached to a support rod 6a on the floating electrode 6 side and a ground gap electrode 7b provided on a support rod 8a.
and a gap 7c formed between the gap electrode 7a and the ground gap electrode 7b. A current detecting current transformer 8 is provided on the support rod 8a and led out to the outside via a lead wire 8b, thereby configuring a pressure monitoring device 1o.

Next, the effects of this embodiment will be described. High voltage side capacitance C1 between floating electrode 6 and conductor 2, low voltage side capacitance C2 between floating electrode 6 and tubular container 18
A potential is always applied to the floating electrode 6 due to the capacitance partial pressure between the floating electrode 6 and the floating electrode 6. That is, the same potential is always applied to the gap electrode 7a having the same potential.

Here, the relationship between SF6 gas pressure and fracture stress is shown in FIG. That is, the vertical axis shows the destructive stress (kv/]), the horizontal axis shows the SF6 gas pressure P (kv/aI-abs), and the SF when an AC voltage is applied between a ball gap with a relatively small gap, When the relationship between gas pressure and fracture stress is shown, it can be seen that fracture stress increases in proportion to SF and gas pressure, as is the case with characteristic engineering.

In other words, if the SF gas 4 shown in Figure 1 is sealed at a rated pressure of 4 kg/ff1-abs, but the pressure drops to 2 kg/aJ-abs due to a leak, for example, the breaking stress will be halved. show what will happen. The gap length of the measurement gap section 7 is adjusted to the induced voltage of the floating electrode 6, and the pressure of the SF and gas 4 in the tubular container 1a is set so that the measurement gap section 7 does not discharge at the rated pressure and is allowed by leakage. It is adjusted appropriately so that it discharges below the lock pressure. Further, the discharge current when the measurement gap portion 7 discharges is detected by a current detection current transformer 8 attached to a support rod 8a at ground potential, and the signal is transmitted via a lead wire 8b to trip a circuit breaker (not shown), for example. By setting it as a signal, the circuit of the pipe air bus 1 can be interrupted.

In this manner, according to the present embodiment, an inexpensive pressure monitoring device for a pipeline air bus bar that prevents a decrease in dielectric strength can be obtained without requiring conversion such as temperature correction as in the prior art.

Next, a first alternative 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. In the embodiment of the present invention, the current detecting current transformer 8 is housed inside the protruding container 5, but in FIG. The support rod 8a is passed through the insulating member 11 airtightly, and one end of the support rod 8a is fixed to the grounding support fitting 12, and the current detection current transformer 8 is attached to the outside of the projecting container 5 of the support rod 8a via the lead wire 8b. and derive it. In this way, there is an advantage that the projecting container 5 can be made smaller.

Next, a second alternative embodiment of the present invention will be described with reference to FIG. The same parts as in FIG. 1 are given the same reference numerals. That is, in order to adjust the potential of the floating electrode 6,
The capacitor 13 supports the support rod 6a and also supports the gap electrode 7a having the same potential as the floating electrode 6.

With this configuration, the conductor 2 (see Figure 1)
Even if the diameter of the tubular container 1a changes, the capacitor 13
By appropriately changing the capacitance of the floating electrode 6, the potential of the floating electrode 6 can be kept constant regardless of the size of the conductor 2 and the tubular container 1a. That is, there is an advantage that the same pressure monitoring device W110 can be used for pipe air buses having different insulation classes.

Next, a third alternative embodiment of the present invention will be described with reference to FIG. The same parts as in FIG. 1 are given the same reference numerals. That is, a float electrode 6, a measurement gear part 7. A current sensing current transformer 8 is housed to form a pressure monitoring device 10 . Measurement gap section 7
A current detection current transformer 8 is provided on the ground side support rod 8a, and one end of the support rod 8a is fixed to the inside of the flexible projecting container 15. When the pressure of the SF gas 4 in the tubular container 1a falls below the rated pressure, the balance between the pressure of the SFB gas 4 in the tubular container 1a and atmospheric pressure is lost, and the flexible projecting container 15 contracts. Accordingly, the measurement gap section 7
This has the advantage that the gap length is also reduced, and discharge occurs in the measurement gap section 7 below a predetermined pressure difference, making it possible to monitor the pressure.

Next, a fourth alternative 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. That is, the support rod 8a on the ground side of the measurement gap portion 7 is passed through the bottom plate 5a of the protruding container 5 through the backing 17 and brought out to the outside, and the gap adjustment nut 16 is screwed into the threaded portion 18 provided on the support rod 8a. Fix it with. This gap adjustment nut 16 has the role of varying the length of the gap 7c of the measurement gap section 7. With this configuration, when it is desired to check the pressure and withstand voltage strength of the SF6 gas 4, the length of the gap 7c of the measurement gap section 7 can be changed as appropriate.
The gap length is read by discharging, and for example, S
F, the pressure and withstand voltage strength of gas 4 can be known.

In addition, it can be said to be a simple SF and gas insulation detector because it does not particularly require a power source for withstanding voltage tests. In this way, it has the advantage of being able to function both as a pressure monitoring device and as an SF6 gas withstand voltage monitoring device.

Next, a fifth alternative embodiment of the present invention will be described with reference to FIGS. 7 and 8. The same parts and parts having the same functions as those in FIG. 1 are given the same reference numerals. In FIG. 7, in the ground gap electrode 7b of the measurement gap part 7, a hygroscopic insulating member 2 is placed on the gap 7c side opposite to the gap electrode 7a.
Trigger electrode 19 is attached via 0. If water were to get mixed into the SF or gas in the tubular container (not shown), the hygroscopic insulating member 20 would absorb moisture and become conductive, and the electric field of the trigger electrode 19 would become severe, causing the measurement gap 7 to discharge. do. In this way, a drop in the pressure of SF6 gas in the tubular container or a drop in withstand voltage due to moisture contamination occurs,
The circuit of the pipe air bus can be broken by detecting the discharge current when the measurement gap part 7 discharges with a current detection current transformer (not shown) and using the signal as a trip signal for a circuit breaker, for example. can. Note that the trigger electrode 19 may be installed on either one of the gap electrodes 7a and 7b of the measurement gap section 7, and the same effect can be obtained in either case.

Further, in FIG. 8, SF is achieved by providing a hygroscopic and porous insulating member 21 on the gap 7c side of the ground gap electrode 7b of the measurement gap portion 7.

When moisture is mixed into the gas, the hygroscopic and porous insulating member 21 absorbs moisture and becomes conductive, shortening the length of the gap 7c of the measurement gap portion 7 and causing discharge. Here, the hygroscopic property and the porosity of the porous insulating member 21 are intended to increase the SF of this insulating member during cleaning, which is converted into a gap length in gas. Although the hygroscopic and porous insulating member 21 has been described as being disposed on the ground gap electrode 7b, it may also be provided on the gap electrode 7a side.
, 7b, and the effect is the same either way.

Next, a sixth embodiment of the present invention will be described with reference to FIG. The same parts or parts having the same functions as those in FIG. 1 are given the same reference numerals. An inductance 22 is inserted and connected to the support rod 6a of the gap electrode 7a having the same potential as the floating electrode 6 so as to be connected in series. This inductance 22 is designed so that its impedance is sufficiently smaller than the impedance due to the low-voltage side capacitance formed in the measurement gap 7 for AC voltage, and conversely, it is made sufficiently small for abnormal voltages such as lightning surges. Select a value so that it is large. Further, when the low voltage side capacitance formed by the measurement gap section 7 is insufficient, a capacitor (not shown) can be provided in parallel with the measurement gap section 7. In this way, even if an overvoltage is applied to the measurement gap section 7 when an abnormal voltage such as a lightning surge occurs, there is an advantage that discharge can be suppressed by the inductance 22.

Next, a seventh alternative embodiment of the present invention will be described with reference to FIG. 1O. The same parts or parts having the same functions as those in FIG. 1 are given the same reference numerals. That is, the opening in the protruding container 5 is sealed with the insulating member 23 with a seal, the floating electrode 6 is brought out into the tubular container 1a, and the support rod 6a is supported so as to pass through the insulating member 23 with a seal in an airtight manner. ,
A gap electrode 7a is provided inside the protruding container 5, and a gap 7c is provided between the gap electrodes 7a, 7b to form a measurement gap portion 7. Support rod 8a of this gap electrode 7b
A current detecting current transformer 8 is provided at , and the outside is led out via a lead wire 8b. Furthermore, the inside of the protruding container 5 and the inside of the tubular container 1a are connected to piping 25. The projecting container 5 is connected via a valve 26 and a pressure cage 27, and is further provided with an exhaust valve 29.

With this configuration, the pressure monitoring device 10 is normally operated with the valve 26 open and the exhaust valve 29 closed.
It acts as. Also, close the valve 26 and close the exhaust valve 2.
9 is gradually opened and the pressure discharged by the measurement gap section 7 is read by the pressure cage 27, whereby the insulation strength of the SF and gas 4 can be detected.

Although each of the above-mentioned embodiments describes a gas-separated pipeline air bus, it is also possible to install a pressure monitoring device in each gas-separated device, that is, in each device of a gas-insulated switchgear. Needless to say, similar effects can be obtained.

〔Effect of the invention〕

As explained above, according to the present invention, by providing a protruding container, a bloating electrode, a measurement gap, and a current detection current transformer, there is no need to convert temperature correction, etc., and the dielectric strength It is possible to provide an inexpensive pressure monitoring device for gas-insulated electrical equipment that detects a drop in pressure and prevents accidents.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of the pressure monitoring device for gas insulated electrical equipment of the present invention, FIG. 2 is a diagram of the discharge characteristics of the measurement gap portion of the pressure monitoring device of FIG. 1, and FIG. FIG. 4 is a cross-sectional view of a main part of another embodiment of the present invention, FIG. 5 is a cross-sectional view of a main part of a second other embodiment of the present invention, and FIG. FIG. 6 is a cross-sectional view of a main part of a fourth other embodiment of the present invention, and FIGS. 7 and 8 are cross-sectional views of main parts of a fifth other embodiment of the present invention. 9 is a cross-sectional view of a main part of a sixth other embodiment of the present invention, FIG. 10 is a cross-sectional view of a main part of a seventh other embodiment of the present invention, and FIG. FIG. 2 is a cross-sectional view of a gas-insulated electrical device. 1... Pipe air bus bar, 1a... Tubular container, 2...
Conductor, 3... Post type insulating spacer, 4... SF,
Gas, 5... Projection container, 5a... Bottom plate, 6... Floating electrode, 7... Measurement gap portion, 7a...
・Gap electrode, 7b... Ground gap electrode, 7c・
... Gap, 8... Current detection current transformer, 9... Support member, 10... Pressure monitoring device, 13... Capacitor, 15... Flexible protruding container, 16... Gap adjustment nut , 17... Backing, 18... Threaded portion, 20... Hygroscopic insulating member, 21... Hygroscopic and porous insulating member, 22... Inductance, 23...
・Insulating member with seal.

Claims (8)

[Claims] (1) A conductor supported through an insulator is housed in a container and a gas insulating medium is sealed to form a gas insulated device, and a pressure monitoring device is provided in the container, and this pressure monitoring device is installed in the container. A protruding container that protrudes outward and opens inward is provided, a floating electrode supported via a support member and facing the conductor is provided within the projecting container, a gap electrode having the same potential as the floating electrode, and a gap electrode having the same potential as the floating electrode. and a ground gap electrode facing each other, a measurement gap section is provided between the floating electrode and the ground,
Further, a pressure monitoring device for gas-insulated electrical equipment, characterized in that a current detection current transformer is provided on the ground gap electrode side of the measurement gap portion. (2) A pressure monitoring device for gas insulated electrical equipment according to claim 1, wherein the current detection current transformer is provided outside the protruding container. (3) A pressure monitoring device for gas-insulated electrical equipment according to claim 1, wherein the supporting member supporting the floating electrode and the gap electrode having the same potential is formed of a capacitor. (4) A pressure monitoring device for gas-insulated electrical equipment according to claim 1, wherein the protruding container is formed by a flexible container, and the ground gap electrode is fixed to the inside of the flexible container. (5) A support rod of a ground gap electrode at earth potential projects outside the projecting container, and a nut is screwed into the support rod via a threaded portion to adjust the gap length of the measurement gap portion. 2. A pressure monitoring device for gas insulated electrical equipment according to item 1. (6) Provide a trigger electrode via a hygroscopic insulating member on the side opposite to the gap of one of the gap electrodes in the measurement gap section, or on the side opposite to the gap of one of the gap electrodes in the measurement gap section A pressure monitoring device for gas insulated electrical equipment according to claim 1, wherein a hygroscopic and porous insulating member is disposed on the pressure monitoring device. (7) A pressure monitoring device for gas-insulated electrical equipment according to claim 1, wherein an inductance is provided in series between the floating electrode and the gap electrode, and these are integrally supported by a support member. (8) The support member supports the floating electrode and airtightly partitions the opening and the inside of the protruding container, and a valve and a pressure cage are provided in the piping connecting the inside of the container and the inside of the protruding container, and the protruding container is provided with a valve and a pressure cage. A pressure monitoring device for gas insulated electrical equipment according to claim 1, further comprising an exhaust valve that can communicate with the atmosphere.