Section instantaneous power-based method of positioning fault sections of distribution network lines

Abstract

The invention discloses a section instantaneous power-based method of positioning fault sections of distribution network lines. A DC component of the section instantaneous power of a non-fault section rarely changes during normal running and fault occurrence, and a value of the DC component is a minimum positive number; a DC component of the section instantaneous power of a fault section increases prior to decreasing and is up to a maximum during a period of from fault occurrence to acting time of an arc suppression coil and a period when stable compensating current is output; therefore, according a multiple of increase of the DC component of the instantaneous power after fault occurrence, the fault section can be determined, and fault positioning is achieved. By making use of waveform data of a whole process from the fault occurrence to the acting time of the arc suppression coil, 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 during single-phase ground faulting is well solved, and no interference is caused to a system.

Description

Technical field [0001] The invention relates to a fault diagnosis method for a distribution network line, in particular to a distribution network line fault section location method based on the instantaneous power of the section. 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, 70% of which are caused by single-phase grounding 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 grounding faults in distribution networks, reliable fault line selection and location methods have been lacking due to weak fault characteristics. As people's requirements for the automation level of distribution networks increase, it is more urgent to fundamen...

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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