Method for positioning single-phase earth fault section of in-situ power distribution network

Abstract

The invention discloses a method for positioning a single-phase earth fault section of an in-situ power distribution network. The method comprises the steps that section positioning is performed on faults of a bus and a boundary branch in a station by adopting a method of combining transient direction parameter comparison and zero-sequence current correlation coefficient comparison; a transient direction parameter is calculated according to the fault phase and used for positioning a single-phase earth fault section of a power distribution network tie line; a GOOSE peer-to-peer communication network is established among the distribution network terminals and is used for transmitting the transient direction parameters of adjacent intervals, and the distribution network terminals carry out fault section positioning on inter-station tie line single-phase earth faults according to the difference between the symbols of the switch transient direction parameters and the symbols of the received adjacent switch transient direction parameters; and each distribution network terminal cuts off a fault adjacent switch to complete fault local isolation according to a single-phase grounding single fault section positioning result, and switches on an interconnection switch to complete power supply recovery of a non-fault area. The technical problem that a reliable means for positioning the omnibearing single-phase earth fault section of the power distribution network is not available is solved.

Description

Technical field [0001] The invention belongs to the technical field of distribution network fault location, and in particular relates to a local distribution network single-phase ground fault section positioning method. Background technique [0002] Medium and low voltage distribution networks are mostly small current grounding systems with complex network topology. Single-phase grounding faults account for more than 80% of the total distribution network faults. After a single-phase grounding occurs, the increase in the voltage of the sound phase may cause insulation breakdown and cause an accident. At the same time, due to reasons such as weak fault current and unstable arc, fault section location has always been a difficult issue, affecting power supply reliability. [0003] The existing automatic positioning methods for single-phase ground fault sections include: relying on the grounding line selection device and the distribution network terminal recloser type FA, but thi...

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Problems solved by technology

[0002] The medium and low voltage distribution network is mostly a small current grounding system, and the network topology is complex. Single-phase grounding faults account for more than 80% of the total distribution network faults. After a single-phase grounding occurs, the rise of healthy phase voltage may cause insulation breakdown and cause accidents. At the same time, due to reasons such as weak fault current and unstable arc, fault section location has always been a difficult problem, which affects power supply reliability

[0003] The existing automatic positioning methods for single-phase ground fault sections include: relying on the grounding line selection device and the method of matching the recloser type FA of the distribution network terminal, but it will bring problems of power outages and many switching operations on the whole line; based on upstream and downstream The zero-sequence current correlation comparison algorithm has a large amount of communication data and has high requirements for synchronization; based on the upstream and downstream transient zero-sequence power direction comparison algorithm, it is necessary to obtain zero-sequence voltage, which is usually not applicable to pole-mounted switches and ungrounded systems; based on zero-sequence The algorithm of sequence current RMS comparison is easily affected by CT unbalanced current and transition resistance; the algorithm using variational mode decomposition (VMD) theory, the signal extraction calculation is complicated, and the reliability needs to be verified; etc.

At present, most of these methods have been studied in principle, and some of them only stay in the simulation stage, without fully considering the field conditions, including the input of analog quantities required by the algorithm, communication bandwidth and reliability, and data synchronization requirements, so their application scenarios are subject to Currently, there is no reliable method for all-round single-phase ground fault section location in distribution network

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