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. There are many points to be monitored, and a large number of voltage transformers need to be installed, resulting in a very high cost; the additional voltage transformers increase the workload of wiring and angle correction, and at the same time, the newly added voltage transformers change the distribution of the primary network. Electrical parameters can easily lead to overvoltage problems such as electromagnetic resonance, making it difficult to popularize and apply

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