Distribution network single-phase grounding fault section positioning method and system

Abstract

The invention discloses a distribution network single-phase grounding fault section positioning method and system. The method comprises a system control terminal and a plurality of online monitoring terminals which are arranged on a distribution line in a scattered manner and are in communication connection with the control terminal. The online monitoring terminals detect voltage and current of three single phases, and judge a fault phase according to an effective value of the voltage; fault recording is performed on voltage and current in a predetermined time interval containing a fault starting moment; three phases of current in fault recording are synthesized into zero-sequence current; and the system control terminal realizes judgment on whether monitoring points of a feeder are positively related or not through calculating and analyzing zero-sequence current values which are sampled, calculated and synthesized by the adjacent online monitoring terminals, and further judges a section in which the distribution fault point is located. The method disclosed by the invention is wide in application range and easy to implement, and does not need to configure a zero-sequence voltage transformer and a zero-sequence current transformer at monitoring points of a distribution network, so that the construction investment and maintenance cost of the system is saved, and problems such as electromagnetic resonance brought about by additionally arranging a voltage transformer on the feeder are solved at the same time.

Description

technical field [0001] The invention relates to the technical field of distribution network fault detection and analysis, in particular to a method and system for locating a single-phase ground fault section of a distribution network. Background technique [0002] The probability of single-phase ground faults in the distribution network is very high. For ungrounded systems, the traditional section location method based on steady-state quantities can be realized. The difficulty is the single-phase ground fault section location of the arc-suppression coil grounding system. The current mainstream technical solution is a section positioning method based on transient information and injection method: [0003] (1) Since the injection method needs to install relatively expensive primary equipment in the substation, it is inconvenient to operate and maintain, and its application range is narrow; [0004] (2) The transient quantity method is based on the amplitude value and phase re...

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Problems solved by technology

[0003] (1) Since the injection method needs to install relatively expensive primary equipment in the substation, it is inconvenient to operate and maintain, and its application range is narrow;

[0004] (2) The transient quantity method is based on the amplitude value and phase relationship between the transient zero-sequence voltage and the zero-sequence current of each section. A voltage transformer/sensor is installed on the distribution line where it needs to be detected

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