Discharge energy function-based method of positioning fault sections of distribution network lines

Abstract

The invention discloses a discharge energy function-based method of positioning fault sections of distribution network lines. Discharge energy of a non-fault section rarely changes during normal running and fault occurrence, and a value of the discharge energy is a minimum positive number; a DC component of a discharge energy function of a fault section increases prior to decreasing, and the DC component is up to the maximum value during a period of from fault occurrence to acting time of an arc suppression coil and a period when stable compensating current is under outputting; therefore, according to a multiple of increase of the discharge energy after fault occurrence, the fault section can be judged, and fault positioning is achieved. By making use of waveform data of the whole process of from fault occurrence to the acting time of an arc suppressor, the use of zero-sequence current is avoided, the problem that the existing general low-current ground system has weak fault current, poor reliability and low sensitivity in case of single-phase ground fault is well solved, and no interference is caused to a system.

Description

technical field [0001] The invention relates to a method for diagnosing faults of distribution network lines, in particular to a method for locating fault sections of distribution network lines based on a discharge energy function. Background technique [0002] According to statistics, during the operation of the power system, power outages caused by distribution network faults account for more than 95% of the total power outages, of which 70% are caused by single-phase ground faults or busbar faults. The neutral point of domestic and foreign distribution networks widely adopts non-effective grounding (small current grounding) to avoid power supply interruption when a single-phase grounding fault occurs. For single-phase-to-ground faults in distribution networks, due to weak fault characteristics, there has been a lack of reliable fault line selection and location methods. With the improvement of people's requirements for distribution network automation level, it is more ur...

AI Technical Summary

Problems solved by technology

Injection signal methods include "S" injection method, AC-DC integrated injection method and parallel neutral resistance method. These methods increase the interference to the system and cannot detect instantaneous and intermittent ground faults.

Section location based on fault characteristic quantity includes zero-mode current comparison method, section zero-sequence admittance method, zero-sequence reactive power direction method, location based on phase current mutation, residual incremental method, traveling wave method, etc. This type of method has key problems such as difficulty in obtaining feature quantities and precise signal synchronization, and some methods have extremely low reliability when high-impedance grounding

[0004] The current positioning methods only use the data after the fault occurs, while ignoring the use of pre-fault information

At the same time, most positioning methods only consider zero-sequence current information (three-phase information is required), which requires high transformers and complicated information acquisition, and these methods will fail when the data is missing

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