Power distribution network grounding fault line selection method

Abstract

The invention discloses a power distribution network grounding fault line selection method. According to the method, a fifth harmonic method, an active component method and a transient energy method are adopted to extract fifth harmonic components, active components and transient energy from zero-sequence current signals to serve as fault features, fault measures of the zero-sequence current signals are defined, then the fault measures serve as input of a model, and according to different judgment capacities of fault steady-state and transient information, and by means of the powerful macroscopic search capability and the good global optimization performance of the genetic algorithm, during training, the genetic algorithm is firstly used for searching the weight of the neural network, the search range is narrowed down, and then the BP network improved by the LM is combined, and then a four-layer neural network of an improved LM-BP algorithm model based on a genetic algorithm is formed to carry out accurate solution so as to achieve the purpose of global search, and local minimum can be avoided, so that the line selection model achieves relatively high precision so as to improve the stability and accuracy of line selection.

Description

Technical field [0001] The present invention belongs to the technical field of distribution network fault discriminant, and,,,,,,,, Background technique [0002] The most common fault form in the distribution system is single-phase ground fault. After a single phase phase failure, the neutral point non-effective grounding system occurs, since only a high impedance current loop can only be constituted between the fault point and the neutral point, so that the grounding point current of the system is small, and the signal is difficult to capture. It is difficult to have a fault line to be discovered. However, when the small current grounding system is single-phase, the system's line voltage is still three-in-line, in order to avoid the sudden disconnection of production, there is no need to trip immediately, the power sector stipulates that the system remains for 1-2 hours. At this time, the sound phase voltage rises to normal. Double, if long-termband fault operation, the system ...

AI Technical Summary

Problems solved by technology

This will cause unnecessary short-term power outages on sound lines. At the same time, after selecting faulty lines, the workload of manual line inspection to find fault points is also very heavy, which is not conducive to rapid fault removal, increases power outage time, and reduces power supply reliability.

[0003] When the grounding occurs when the phase voltage and phase are zero, the transient process will be very inconspicuous, especially when the fault grounding resistance is high, the transient fault characteristics can hardly be seen, which will cause incorrect line selection

However, the steady-state line method often ignores the transient information with rich fault characteristics, resulting in low line selection accuracy.

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