Non-full-phase protecting circuit of circuit breaker

Abstract

A non-full-phase protecting circuit of a circuit breaker comprises a starting circuit, an outlet circuit, a tripping circuit and a power supply used for supplying power to all the circuits, wherein the starting circuit is connected between a positive electrode and a negative electrode of the power supply and comprises a switch-off normally-closed contact set, a switch-on normally-open contact set and a time relay which are all connected in series in sequence, three phases of switch-off normally-closed contacts are connected in parallel to form the switch-off normally-closed contact set, three phases of switch-on normally-open contacts are connected in parallel to form the switch-on normally-open contact set, and the outlet circuit comprises outlet relays in series connection, and a normally-open contact of the time relay. The non-full-phase protecting circuit of the circuit breaker is characterized in that the tripping circuit is provided with normally-open contacts of the outlet relays and an operating mechanism of the circuit breaker, the input end of the tripping circuit is connected to the starting circuit on the output side of the switch-off normally-closed contact set, and the output end of the trigging circuit is connected with the negative electrode of the power supply. With the non-full-phase protecting circuit of the circuit breaker, breakover of the tripping circuit and abnormal tripping of the circuit breaker which are caused by error operation on the time relay can be avoided, and thus normal work of the circuit breaker is not influenced.

Description

technical field [0001] The invention relates to a circuit breaker non-full-phase protection circuit. Background technique [0002] In power grids with a voltage level of 220kV and above, circuit breakers operated in separate phases are generally used. Due to equipment quality and operation and other reasons, abnormal states in which three-phase circuit breakers operate inconsistently may occur during operation, and zero-sequence, Negative sequence current will have an adverse effect on the system, and even cause malfunction of protection and automatic devices. In order to reduce the harm to the system when the three phases of the circuit breaker are inconsistent, the three-phase inconsistent protection of the circuit breaker (not all-phase protection) should be installed, and the circuit breaker with three-phase inconsistency will be taken out of operation to ensure the normal operation of the system. [0003] refer to figure 1 As shown, the existing non-full-phase protect...

AI Technical Summary

Problems solved by technology

[0003] refer to figure 1 As shown, the existing non-full-phase protection circuit mainly includes: start circuit 1, exit circuit 2, trip circuit 3 and a power supply for supplying power to each circuit, wherein the start circuit 1, exit circuit 2, and trip circuit 3 are connected in parallel Between the positive and negative poles of the power supply, the starting circuit 1 includes the closing normally open contact group, the opening normally closed contact group and the time relay K7 in series, and the closing normally open contact group consists of three-phase closing normally open contacts QF1A, QF1B, and QF1C are connected in parallel, and the opening and closing contact group is composed of three-phase opening and closing contacts QF2A, QF2B, and QF2C in parallel; the exit circuit 2 includes the exit relay Q7 connected in series and the time relay K7 The normally open contact K7-1 of the switch is controlled by the time relay K7; the trip circuit 3 is provided with the normally open contacts Q7-A, Q7-B, and Q7-C of the export relay Q7, and the switch is controlled by the export relay Q7; The above non-full-phase protection circuit has the following defects: when the three phases of the circuit breaker are consistent and the time relay K7 malfunctions, it will cause the tripping circuit 3 to conduct and cause the circuit breaker to trip abnormally, affecting the normal operation of the circuit breaker; When the outlet relay Q7 malfunctions, it will also cause abnormal tripping of the circuit breaker and affect the normal operation of the circuit breaker.

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