Verification system of grounding direction protective relay

Abstract

The invention discloses a verification system of grounding direction protective relays; a secondary side of a zero sequence voltage transformer in the verification system is connected with a first wiring terminal and a third wiring terminal of a plug-in; an A-phase end and an N-phase end of a verification instrument voltage channel are respectively connected with a plurality of voltage coils of verified relays through a second wiring terminal and a fourth wiring terminal of the plug-in, and the phase end and the coil have same polarity; a voltage meter is connected in parallel with the A-phase end and the N-phase end of the verification instrument voltage channel; a plurality of zero sequence current transformers and ammeters are connected in series in sequence between the A-phase end and the N-phase end of the verification instrument voltage channel, and have same polarity; a plurality of output ends of the zero sequence current transformers are respectively connected in sequence with the plurality of current coils of the verified relays, and the output ends and the coils have same polarity. The verification system can simultaneously verify all grounding direction protective relays of one busbar; the zero sequence current transformers and the zero sequence voltage transformers are connected in the system; wiring correctness can be verified in the verification process, thereby reducing labor intensity of the verification work, and improving verification efficiency.

Description

technical field [0001] The invention relates to a verification system for a grounding direction protection relay. Background technique [0002] The ground directional protection relay is the main protection in the event of a single-phase ground fault on the motor or cable line. When single-phase grounding occurs on the motor or cable line, the non-grounded phase-to-ground voltage increases, and can rise to a maximum of 1.732 times the phase voltage, which is likely to cause phase-to-phase short circuit. In addition, although the current flowing through the grounding point is not large, it is very destructive due to the high voltage and has the nature of arc, which is easy to burn the stator core of the motor or cause the cable to explode. [0003] Therefore, when a single-phase ground fault occurs on the motor or cable line, the sensitivity, correctness and selectivity of the grounding direction protection relay are particularly important. With the development and applicat...

AI Technical Summary

Problems solved by technology

[0005] Since the verification method does not connect the secondary line of the zero-sequence current transformer and zero-sequence voltage transformer to the test circuit, there is no way to verify the correctness of its wiring.

Especially when the bus is charged, the zero-sequence voltage transformer of the bus is running. When disconnecting and connecting the zero-sequence voltage connections of the protective relays in each grounding direction, the probability of a short circuit of the zero-sequence voltage transformer is increased, resulting in a fault.

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