JPH03257731A - Tank type gas-blast circuit-breaker with closing resistor - Google Patents

Abstract

PURPOSE:To enhance the reliability of a support insulator supporting resistors, and thereby prevent the occurrence of failures due to grounding just after interruption by supporting one end of each resistor with the support insulator connected onto a connecting conductor which is connected to the other equipment. CONSTITUTION:In the stationary side of a circuit breaker, a support insulator 20 is fixed onto a connecting conductor 12 by which the breaker is connected to the other equipment, within the circuit breaker, and the stationary end sections of resistors 3b and 3c are supported by the support insulator 20 via the connecting conductor 3d of both of the resistors. Current is applied to the resistors 3b and 3c only for about 10ns from the functional point of view. No current does flow therefore into each resistor for the time other than the aforesaid time for making current, neither potential difference is built up between the connecting conductors 12 and 3d nor voltage is applied to the support insulator 20. By this constitution, insulating properties just after interruption are lowered less, and the insulating cylinder 20 supporting the resistors 3b and 3c is prevented from being stressed by voltage at all times.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a tank-type gas circuit breaker with closing resistance that suppresses overvoltage generated during opening and closing.

(Prior art) In Japan, in circuit breakers used in high-voltage systems such as 550kV systems, it is common to insert a closing resistor to suppress switching surges that occur in the circuit when the circuit is closed. . In this system, a closing contact connected to a closing resistor is installed in parallel with the main contact of the circuit breaker, and when the circuit breaker is closed, the closing contact is closed before the main contact, and the main contact is closed while the closing overvoltage is suppressed by the closing resistance. It is something that will be done.

Generally, in such a circuit breaker having a closing resistance, the optimum resistance value of the closing resistor is approximately the same value at the same rated voltage, and therefore the heat capacity that the resistor must handle at the time of closing is also approximately the same. The size of the resistor used is determined by the heat capacity that the material of the resistor can handle and the withstand voltage value of the material.

By the way, with the recent improvement in breaking performance, the number of breaking points has been reduced, and circuit breakers are now becoming one-point breaking, and accordingly, the number of closing resistance contacts is also being reduced to one point. However, due to the above-mentioned reasons, the magnitude of the closing resistance is not easily reduced, so that the closing resistance is relatively large compared to the closing contact, etc., and the problem is how to support this closing resistance. In order to solve this problem, for example,
The invention described in Publication No.-89127 has been proposed as a prior art.

FIG. 2 shows an example of such a conventional technique, in which the supporting structure of the closing resistor of a horizontal circuit breaker is improved. In this prior art, a resistance contact part 3 is connected in parallel with an arc extinguishing chamber 2 in a gas tank 1 of a circuit breaker,
The movable ends of the arc extinguishing chamber 2 and the resistance contact portion 3 (right end in the figure) are supported by the gas tank 1 by an insulating tube 5 via a movable support member 4. A mechanism box 6 is attached to this end of the gas tank 1, and a drive section is housed inside the mechanism box 6.

The arc extinguishing chamber 2 includes a movable electrode 2a supported by an insulating rod 7 driven by a drive unit (not shown) in a mechanism box 6, a buffer cylinder 2b fixed to the movable electrode 2a, and an insulating nozzle 2cs buffer cylinder 2b. a movable part consisting of a buffer piston 2d which is slidable and fixed to the arc extinguishing chamber; a fixed part having a fixed electrode 2e disposed opposite to the movable electrode; It is composed of an insulating cylinder 2f provided.

The resistance contact portion 3 is a closing resistor 3b electrically connected to the fixed portion side of the arc extinguishing chamber 2 via a connecting conductor 3a.

3c, a connecting conductor 3d connecting the making resistors 3b and 3c in series, a fixed side closing contact 3e and a movable side closing contact 3f connected in series with the closing resistors 3a and 3c, and a movable side closing contact 3f connected to the movable side. It is composed of a support conductor 3g that is connected and fixed to the support member 4. In addition, the closing resistances 3b and 3c
Due to the insulating tube 8 provided at the 3d portion of the connecting conductor,
It is supported at the bottom of the gas tank 1.

A connecting conductor 10 is connected to other equipment from the movable side of the arc extinguishing chamber.
The fixed side has a connecting part 11 and a connecting conductor 12.
, a connector 13 and an insulating spacer 14 that supports these, and is connected to other equipment.

(Problem to be Solved by the Invention) However, in the prior art having such a configuration, since the closing resistors 3b and 3c are supported by the gas tank 1 via the insulating cylinder 8, when the circuit breaker is closed or opened, Even in extreme conditions, when voltage is applied to the fixed side of the circuit breaker, electrical stress is constantly applied to the insulating tube 8.

In addition, this type of buffer type gas circuit breaker blows gas compressed by a buffer cylinder 2b, guided by an insulating nozzle 2C, against an arc generated between a movable electrode 2a and a fixed electrode 2e when interrupting current. As a result, a large amount of hot gas heated by the arc is generated in order to extinguish the arc. This hot gas moves in the direction of the arrow in Fig. 2, but if the insulating cylinder 8 is on the fixed side, this hot gas will reduce the insulation performance of the gas near the insulating cylinder 8, and the gas gap will decrease. However, there is a risk that the insulation performance in the creeping direction of the insulating tube 8, which has a weak insulation performance, will deteriorate, and there is a possibility that an internal circuit will occur immediately after the interruption.

The present invention was proposed in order to solve the problems of the prior art as described above, and its purpose is to minimize the deterioration of insulation performance immediately after disconnection, and to maintain constant voltage on the insulating tube supporting the closing resistor. To provide a highly reliable closing resistance bone tank type gas circuit breaker that is not subjected to stress.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the closing resistance bone tank type gas circuit breaker of the present invention has a structure in which the circuit breaker is connected to other equipment. The structure is characterized in that a support insulator is fixed to the connecting conductor, and the making resistor is supported by the support insulator.

(Function) In the present invention having the above-mentioned configuration, the connection conductor and the closing resistor have a current of about 100 mL, through which a current flows through the resistor at the time of closing.
Since everything other than ns is at the same potential, no electrical stress is applied to the support insulator supporting the closing resistor except when the circuit breaker is closed, and there is no fear of dielectric breakdown along the support insulator even when the circuit breaker is disconnected. do not have.

(Example) An example of the present invention will be described below with reference to FIG. Note that the same members as those in the prior art shown in FIG. 2 are designated by the same reference numerals, and explanations thereof will be omitted.

In this embodiment, the movable end portions of the closing resistors 3b and 3c are supported by the fixed closing contact 3e of the resistance contact portion 3, as in the prior art described above. On the other hand, on the fixed side of the circuit breaker,
A support insulator 20 is fixed to the connection conductor 12 in the circuit breaker for connecting the circuit breaker to other equipment, and the fixed side ends of the closing resistors 3b and 3c are connected to the support insulator 20. is supported via the connecting conductor 3d.

In this embodiment having such a configuration, the closing resistor 3
b, 3c, due to their required functions, approximately 1 at the time of input.
0nsL or no current flows. During the period in which this current flows, a potential difference is generated between the closing resistors 3b and 3c, and a potential difference is generated between the connecting conductor 12 and the connecting conductor 3d connecting the closing resistors 3b and 3c. As a result, a voltage is applied to the support insulator 20. However, during periods other than this, current flows through the resistor, so the connecting conductor 12
There is no potential difference between the supporting insulator 2 and the connecting conductor 3d.
No voltage is applied to 0 either. As a result, supporting insulator 20
Since no electrical stress is constantly applied to the insulation, insulation reliability can be improved. In addition, when shutting off, the hot gas generated at the time of shutting off is blown toward the stationary side as in the prior art shown in FIG. As a result, there is no need to worry about deterioration of the insulation performance of the supporting insulator 20,
As a result, a ground fault is less likely to occur immediately after the current is cut off.

[Effects of the Invention] As described above, according to the present invention, despite the simple means of supporting one end of the closing resistor with a supporting insulator fixed to a connecting conductor for connecting to other equipment, It is possible to provide a highly reliable tank-type gas circuit breaker with a closing resistor that can improve the reliability of the support insulator that supports the resistor and prevent the occurrence of a ground fault immediately after shutoff.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of a tank-type gas circuit breaker with closing resistance according to the present invention, and FIG. 2 is a sectional view showing an example of a conventional tank-type gas circuit breaker with closing resistance. 1... Gas tank, 2... Arc extinguishing chamber, 3... Resistance contact section, 3b, 3c... Closing resistance, 3d... Connection conductor, 12... Connecting the circuit breaker to other equipment A connecting conductor in the circuit breaker for the purpose of connecting, 20... supporting insulator.

Claims (1)

[Claims] (1) A resistive contact section that is housed in a tank filled with insulating gas and has a closing contact and a closing resistor connected in series to suppress overvoltage during closing, and is electrically parallel to this resistive contact section. In a tank-type gas circuit breaker with a closing resistor that has a main contact section connected to a A tank type gas circuit breaker with a closing resistor, characterized in that the closing resistor is supported.