JPH02165526A - Disconnecting switch - Google Patents

Abstract

PURPOSE:To make it possible to make a disconnecting switch smaller while simplifying the whole manufacturing process which includes that of a resistor by effectively disposing in an electrode structure the resistor for controlling surge voltages generated by reignition. CONSTITUTION:The fixed contact 9 of a fixed electrode 6 is surrounded by a shield 25 which has a ring-shaped electrode 26 at its opening, and the disconnecting switch has a moving electrode 8 which passes through the opening of a resistor shield 25 to open and close the fixed contact 29. A resistor R is provided which is put in its shortcircuited state while being connected to the moving contact 8 being closed and which is inserted into the circuit during reignition; while the disconnecting switch is closed, the resistor R is shortcircuited so that the circuit is not affected at all and, in association with the resistor shield 25 located on the side of fixing, the resistor R effectively restrains surge voltages generated at reignition. The resistor R for restraining surge voltages is divided into two parts, which are installed on the side of the fixed electrode shield and on that of the moving electrode. The disconnecting switch can thus be made smaller than in the case of integrating a resistor therewith.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention is used in SF and gas-insulated switchgear, and is particularly useful as a measure to suppress surge voltages generated during switching operations. This article relates to an improved disconnector.

(Prior art) In power switchgear equipment such as substations, in order to separate the system in which the accident occurred from other healthy systems when a JG fault occurs, to change the operating status of the system.

There are cases where the current flowing through the system is interrupted for the purpose of disconnecting part of the system from other parts during inspection.

In this case, the device that actually interrupts the current flowing through the circuit is a circuit breaker, and after this circuit breaker interrupts the current, it is used to ensure insulation between that part of the circuit and other parts. is the disconnector.

Therefore, this disconnector is basically not required to have the ability to interrupt large currents. However, in power equipment, disconnectors are connected to other equipment such as transformers by cables or gas-insulated busbars;
Disconnectors are required to have the ability to cut off the charging current that charges stray capacitance components in gas-insulated buses, transformers, etc.

In general, a disconnector is configured such that a fixed electrode and a movable electrode are arranged in a metal container, and the movable electrode is made to perform a closing operation or an opening operation by an operating mechanism6.
When a normal disconnector performs an opening operation, the movable electrode separates from the fixed electrode, and the tip of the movable electrode is fixed '11! When the pole is unplugged, the current is cut off at the zero point of the alternating current.

However, at the beginning of the opening operation, when the electrode amount ratio and separation are short, the dielectric strength between the electrodes cannot withstand the re-electromotive voltage that appears between the electrodes after the current is cut off, and dielectric breakdown occurs between the electrodes. . Such dielectric breakdown is called restriking. This restriking occurs between the tip of the fixed electrode and the tip of the movable electrode, generating an arc. Even if restriking occurs, the current value is small, so the current is immediately cut off again.

In this way, in the process of opening the disconnector, current interruption and re-ignition are repeated. As the opening operation progresses, the distance between the disconnector electrodes increases and the dielectric strength also increases. In this way, as the opening operation progresses, the inter-electrode voltage at the time of restriking increases, but if the dielectric strength of the opening operation exceeds the inter-electrode voltage in this way, the repeated restriking stops. The cutoff is completed.

Let us now consider the circuit phenomenon when a restriking occurs during the opening operation of the disconnector. The circuit connected to the disconnector has a power supply, capacitance, and inductance.
When the disconnector is re-ignited, high-frequency vibrations occur in the circuit, resulting in high-frequency overvoltage. Such an overvoltage will occur every time the disconnector is re-ignited, and this high-frequency overvoltage will become larger as the voltage between poles increases when the disconnector is re-ignited. There is also a risk of threatening the insulation of other equipment.

Utility Model Application No. 58-533 as a measure to avoid the danger of high-frequency overvoltage caused by restriking in disconnectors.
There is an oral tradition in Publication No. 32. That is, the disconnector has a fixed contact 9 and a movable electrode 8 disposed inside a metal container 1 so as to be movable relative to each other, as shown in FIG. Made with
A metal electrode 26 is embedded in the tip of the resistor shield 25, and the mutually opposing surfaces of the resistor shield 25 and the movable electrode side shield 11 made of R are made into an arc shape so that the electric field therebetween is made uniform. .

The state of this disconnector shown in FIG. 7 shows the process in the middle of the opening operation.
This shows that the arc 25 comes out from the opening 25a and restriking occurs between its tip and the metal electrode 26 of the resistor shield 25, and a restriking arc 28 is formed. The restriking current at this time flows from the movable electrode 8 to the fixed electrode 6 via the resistor shield 25.

Due to the presence of this resistor shield 25, a current generated during opening or a restriking current flows through this resistor, so that overvoltage is effectively suppressed due to loss in this resistor.

In the electrode structure shown in FIG. 7, the voltage applied to the resistor shield 25 at the time of restriking is shared by the creeping length Ll including its arcuate surface. That is, the portion of the resistor shield 25 that faces the movable metal shield 11 also shares the voltage. This part is arcuate to provide an electric field relaxation effect, and the voltage is shared by the curved surface. Therefore, it is expected that the total length 2 of the resistor shield 25 can be made relatively short and the entire disconnector can be made smaller.6 However, the electrode structure of the disconnector shown in FIG. 7 has the following potential problems. There is. That is, when the shield 25 is configured as shown in FIG. 7, it is necessary to configure the shield 25 so that the current density in each part of the shield 25 is uniform.

In FIG. 8, which shows an enlarged view of the resistor shield 25 in FIG. 7, the amount of heat generated in a unit volume of the resistor due to the current is ρi2 (ρ is the volume resistivity of the resistor).

λ is the current density). Since the temperature rise per unit volume of the resistor can be considered to be linearly proportional to the amount of heat generated, it is proportional to the square of the current density. If the current density differs in each part of a continuous resistor, a temperature difference will occur in each part. When the temperature of the resistor increases, the resistor expands thermally,
If the temperature differs in each part, it will expand at a different rate. As a result.

There is a risk that distortion forces will be generated inside the resistor and the resistor will be damaged.

Therefore, the shield 25 made of this type of resistor is
As shown in detail in FIG. 8, a ring-shaped metal electrode 26 is provided around the tip of the resistor shield 25. As shown in FIG. This ring-shaped metal electrode 26 faces the movable electrode 8, and the restriking arc 28 is always between the movable electrode 8 and the metal electrode 2.
6. Since the volume resistivity of metal is negligibly small compared to that of a resistor, the arc current uniformly flows from each part on the circumference of the metal electrode 26 to the shield 25 made of the surrounding resistor. If a re-ignition arc occurs directly from the movable electrode 8 to the shield 25 of the resistor without adopting such a structure, the current will concentrate on the part of the shield 25 of the resistor where the arc has occurred.
There is a great risk that the temperature in that part will locally rise sharply and the shield 25 made of a resistor will be destroyed.

Next, as shown in FIG. 8, the shield 25 of the resistor must be thinner toward the outer periphery and have a constant cross-sectional area at the overlapped portion. This is also one measure for making the current density uniform as described above.

(AIM to be solved by the invention) However, the shield 25 made of a resistor in this way is
Because it shares the voltage when restriking occurs,
It needs to be long enough to withstand this voltage. Therefore, in recent ultra-high voltage and ultra-ultra high voltage power transmission systems,
It is very difficult to form such a long resistor as a single component, which has to be extremely long, and to uniformly control the components of each part so that the volume resistivity is uniform. There is a problem in that it requires advanced manufacturing technology and is expensive in terms of price.

An object of the present invention is to effectively arrange a resistor in the electrode structure for suppressing the surge voltage generated due to restriking, thereby making the entire structure including the resistor easy to manufacture and miniaturized. The purpose is to provide a disconnector.

[Structure of the invention]

(Means for Solving the Problems) The disconnector of the present invention surrounds the outside of a fixed contact of a fixed electrode with a low-antibody shield made of a resistor having a ring-shaped electrode in an opening, and the resistor shield is In a disconnector having a movable electrode that performs closing/opening operations with a fixed contact through an opening, the circuit is connected to the movable electrode and placed in a short-circuited state in the closed state, and the circuit is closed when restarting. This is characterized by the provision of a resistor to be inserted.

(Function) In the present invention, when the disconnector is in the closed state, the resistor provided on the movable side is in a short-circuited state and is not inserted into the circuit. When the movable electrode is re-ignited, the resistor is unshorted and inserted into the circuit. Therefore, the surge voltage that occurs with restriking is.

This is effectively suppressed by the resistor shield on the fixed side and this resistor.

(Example) The present invention will be described below with reference to each example shown in FIGS. 1 to 6. First, in FIGS. 1 and 2 showing the electrode structure of the disconnector of the present invention, the fixed electrode 6 has a fixed side contact 9, and the contact 9 is surrounded by a resistor shield 25 made of a resistor. A metal ring-shaped electrode 26 is embedded in the opening.

However, in one aspect of the present invention, the fixed side contactor 9 is charged with
It is characterized by the provision of a resistor R connected to the movable electrode 8 that opens the electrode, which is brought into a short-circuit state in the closed state in conjunction with the closing and opening operations, and is inserted into the circuit at the time of re-ignition. That is. In the embodiment shown in FIG. 1, the movable electrode 8 is composed of a three-part connection in the axial direction: a metal portion 8a, a resistor R, and a metal portion 8b, and this resistor R is short-circuited when the movable electrode 8 is in the closed state It is characterized in that it is configured to be short-circuited at the electrode 32. The shorting electrode 32 is supported by the movable shield 11 with an insulator 33.

Next, the operation of the disconnector of the present invention constructed as described above will be explained. In the closed state of the disconnector shown in FIG.
a - shorting electrode 32 - flowing through the metal part 8b of the movable ffi pole 8, so the resistor R is not inserted into the circuit;
The disconnector has no negative effect on the circuit.

On the other hand, when the switching device performs an opening operation and the movable electrode 8 is driven to the right in the figure, the resistor R of the movable electrode 8 leaves the short-circuit range of the short-circuit electrode 32, as shown in FIG. As a result, the resistor R is inserted in series in one circuit.

Furthermore, as shown in FIG. 2, the movable electrode 8 and the resistor shield 25
A restriking arc 28 is generated between the metal ring-shaped electrode 26 and
When this occurs, the restriking current flows through the resistor shield 25 on the fixed side, the ring-shaped electrode 26, and the metal portion 8a of the movable electrode 8.
- resistor R - flows through the metal part 8b. Therefore, the restriking current is effectively suppressed by the combined resistance of the resistor shield 25 on the fixed side and the resistor R of the movable electrode 8.

In the embodiment shown in FIG. 1, the voltage after restriking is shared between the two resistors, the resistor shield 25 and the resistor R. It is possible to construct a disconnector having a resistor that is smaller in size, easier to manufacture, and less expensive than when it is manufactured.

In another embodiment shown in FIG. 3, the resistor portion R of the movable electrode 8 is improved.

In other words, the mechanical strength of the entire movable electrode 8 is reinforced by arranging a plurality of resistors R and a plurality of insulating supports 8c in parallel.

Next, in other embodiments shown in FIGS. 4 and 5,
The movable electrode 8 has a metal portion 8a as shown.

The narrow part 8d of the metal part and the metal part 8b are integrally molded, and the resistor R connected to this movable electrode is formed in a cylindrical shape, and is connected to the sliding contacts 36 and 37 at both ends, and the sliding contact The child 37 is connected to the movable shield 11.

Also in the disconnecting switch shown in FIGS. 4 and 5, when the disconnecting switch is in the closed state shown in FIG. The resistor shield 25 and the resistor R are not inserted in the circuit that flows through the narrow part 8d of the part - the metal part 8b - the sliding contact 37 - the current-carrying contact 38, and flows through the disconnector to the external circuit,
The disconnect switch has no effect.

On the other hand, is the circuit device performing an opening operation and moving? I! When the pole 8 is driven to the right in the figure, the narrow portion 8d of the movable electrode 8 reaches the sliding contact 37 of the resistor R as shown in FIG. 5, and both ends of the narrow portion 8d reach the sliding contact. 36 and 37 respectively, the short-circuit condition of the resistor portion R is released, and the resistor R is inserted in series in the circuit.

In the state shown in FIG. 5, the restriking current due to the restriking arc 28 is caused by the following: fixed electrode 6 - resistor shield 25 - ring-shaped electrode 26 - restriking arc 28 - metal part 8a of movable electrode 8 - sliding The current flows through the contact 36 - the resistor R - the sliding contact 37 - the energizing contact 38 6 Therefore, the resistor through which the restriking current flows is composed of the resistor shield 25 on the fixed side and the resistor R on the movable electrode side. The surge voltage after restriking is effectively suppressed.

Furthermore, in another embodiment shown in FIG.
This is an improved version of the resistor R that is connected to the resistor R.

That is, the resistor portion R is formed into a rond shape, and a plurality of rod-shaped resistors R and a plurality of insulating rods 34 are arranged to reinforce the overall mechanical strength.

〔Effect of the invention〕

As described below, in the present invention, the fixed contact of the fixed electrode is surrounded by a resistor shield having a ring-shaped electrode in the opening, and the fixed contact is connected to and disconnected from the fixed contact through the opening of the resistor shield. It has a movable electrode that performs the operation, and is connected to the movable electrode and placed in a short-circuited state in the closed state,
By providing a resistor that is inserted into the circuit at the time of restriking, even though the resistor is in a short-circuit state when the disconnector is closed, it does not affect the circuit in any way, and at the time of restriking, the resistor remains short-circuited. Combined with the resistor shield on the fixed side, this effectively suppresses the surge voltage that occurs due to restriking. Furthermore, the configuration in which the resistor for suppressing surge voltage is installed separately in two locations, one on the fixed electrode shield side and the other on the movable electrode side, has the advantage that it can be made smaller than when the resistor is made as one piece.

[Brief explanation of the drawing]

1 and 2 are sectional views showing one embodiment of the disconnecting section of the disconnector of the present invention in the closed state and the open state, and FIG. 3 is another embodiment of the resistor section used in the present invention. FIG. 4 and FIG. 5 are cross-sectional views showing other embodiments of the disconnecting section in the closing state and the open state in the disconnecting switch of the present invention, and FIG. 6 is a cross-sectional view showing the resistor used in the present invention. FIG. 7 is a sectional view showing a disconnecting section of a conventional disconnect switch, and FIG. 8 is a sectional view showing the relationship between a resistor shield and a movable electrode. 6...Fixed electrode 8...Movable electrode 8a, 8
b... Metal part 8d... Narrow part 9... Fixed contact 11... Movable side shield 25... Fixed side resistor shield 26... Ring-shaped electrode R... Resistor 28.・Re-ignition arc 32... Short circuit electrodes 33, 34... Insulating support 36.37... Sliding contact 38... Energizing contact agent Patent attorney Yoshiaki Inomata (1 idiot) No. figure

Claims (1)

[Claims] The outside of the fixed contact of the fixed electrode is surrounded by a resistor shield made of a resistor with a ring-shaped electrode in the opening, and the closing/opening operation with the fixed contact is performed through the opening of the resistor shield. A disconnector having a movable electrode, characterized in that it is provided with a resistor that is connected to the movable electrode and placed in a short-circuited state when the movable electrode is turned on, and inserted into the circuit when the movable electrode is turned on again. .