Distribution network single-phase ground fault location method and system based on frequency sweep injection

Abstract

The invention provides a method and system for single-phase ground fault location of distribution network based on frequency sweep injection, which includes several lines to be located, the input ends of several lines to be located are respectively connected to the output ends of three-phase bus bars, and several lines to be located are The output ends of the lines are all electrically connected to the three-phase voltage transformers and three high-voltage switches in turn; it also includes a controllable power supply electrically connected to the three high-voltage switches and scattered on several lines to be positioned, and all located in the three high-voltage switches. Several fault indicators after the switch. The current with wide frequency and adjustable amplitude is injected into the three-phase bus through the controllable power supply. The injection process uses the frequency sweep method. The injection current can be set according to different grid structure parameters, and the optimal injection characteristic current is selected from it. According to the fault indication The real-time characteristic current value generated for the optimal injection characteristic current in each phase of the three-phase bus returned by the device can accurately locate the fault area, which is more accurate than the existing positioning method.

Description

technical field [0001] The invention belongs to the field of single-phase ground fault location of distribution network lines in a three-phase neutral point ungrounded system, and in particular relates to a single-phase ground fault location method and system of distribution network based on sweep frequency injection. Background technique [0002] The medium-voltage distribution network at home and abroad widely adopts the neutral point ungrounded or arc suppression coil grounded operation mode. Compared with the high-voltage transmission network, the medium-voltage distribution network has a high probability of failure, and single-phase ground faults occur frequently. When a single-phase fault is grounded, the non-fault phase-to-ground voltage rises, and the overvoltage may cause the ground fault to be transformed into a phase-to-phase short circuit fault, seriously endangering the system insulation and equipment safety, resulting in tripping and power supply interruption. ...

AI Technical Summary

Problems solved by technology

However, this method has the influence of the injection signal being limited by the capacity of the voltage transformer and the shunting of the distributed capacitance on the injection signal. For the distribution network line architecture with different parameter distributions, using this method will easily lead to failure of fault location.

Images