Low excitation impedance transformer single-phase grounding protection device and protection method

Abstract

The invention relates to a low excitation impedance transformer single-phase grounding protection device and a protection method. Through bypass grounding current shunting, grounding arcs are eliminated, the grounding protection effect is improved, grounding and line selection can be realized, and line selection and fault positioning are accurate. The device comprises three single-phase breakers, a low excitation impedance transformer, a signal generator, a zero sequence current transformer and a control detection device, wherein wire incoming sides of the three single-phase breakers are respectively connected with a corresponding bus through an isolation switch or a separation breaker, wire outgoing sides are connected with an original edge winding of the low excitation impedance transformer, the low excitation impedance transformer is a single-phase three winding dry core transformer having the original edge winding, a secondary edge main winding and a secondary edge secondary winding, one end of the original edge winding is connected with a ground network or a ground row through the zero sequence current transformer, the secondary edge main winding is connected with the signal generator, the secondary edge secondary winding is connected with the control detection device, the secondary edge main winding is for signal injection, and the secondary edge secondary winding is for signal measurement.

Description

technical field [0001] The invention relates to a single-phase grounding protection device and a protection method of a small current grounding system of a distribution network, in particular to a single-phase grounding protection method and a protection method of a low excitation impedance transformer. Background technique [0002] Most of the faults in the small current grounding system of the distribution network are single-phase grounding faults. According to the regulations, it is allowed to operate with single-phase grounding for 1 to 2 hours. ground arc. However, due to the influence of the over-compensation operation mode of the arc-suppression coil, the arc-extinguishing is not complete, and the line selection and fault location are difficult. Using voltage transformers for signal injection for line selection and fault location can solve the problem of line selection and location, but limited by the capacity of voltage transformers, especially in the case of high-i...

AI Technical Summary

Problems solved by technology

However, due to the influence of the over-compensation operation mode of the arc-suppression coil, there are incomplete arc extinguishment, difficulty in line selection and fault location

Using the signal injection method of voltage transformer for line selection and fault location can solve the problem of line selection and location, but limited by the capacity of voltage transformer, especially in the case of high resistance grounding, the accuracy of line selection and location is not high

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