Method for positioning ground faults of distributive small current

Abstract

The invention relates to a method for positioning ground faults of distributive small current. The method includes the following steps: S1. initializing a power distribution power by using the break variable of a transient zero-sequence current, and after the initialization of the power distribution terminal, in addition to recording the wave form of the zero-sequence current, also broadcasting the transient zero-sequence information that is detected by the power distribution terminal; S2. after the power distribution terminal receiving the transient zero-sequence information that is broadcast in the network, searching for the record of the initialization of the break variable with effective time period of the terminal, and if such record exists, comparing the magnitudes of the transient zero-sequence current of the network and the local transient zero-sequence current, and determining the magnitude of the detected zero-sequence current, if the initialization condition is met, initializing a neighborhood detection program, entering the step S3; and S3. performing the neighborhood detection program, using the wave form similarity of the transient zero-sequence current to determine the fault section. According to the invention, the method herein uses the power distribution terminal or an electric cable remote measuring and remote signaling fault indicator, uses distributed algorithm, and determines fault section.

Description

technical field [0001] The invention relates to the field of electric power automation, in particular to a barcode reading method applied to a POS terminal. Background technique [0002] The neutral point of the distribution network in my country and the European continent is widely used as ungrounded or grounded through the arc suppression coil. Due to the small grounding current and the high proportion of intermittent grounding faults, especially the influence of the compensation current of the arc suppression coil, the success rate of conventional line selection devices using power frequency zero-sequence current and harmonic signal faults is low (less than 60%) . The recently developed method of inputting a resistor and injecting a characteristic current signal into the system has significantly improved the success rate, but the investment is large, the safety is poor, and it is not suitable for frequent instantaneous ground faults. The transient current generated at t...

AI Technical Summary

Problems solved by technology

Due to the small grounding current and the high proportion of intermittent grounding faults, especially the influence of the compensation current of the arc suppression coil, the success rate of conventional line selection devices using power frequency zero-sequence current and harmonic signal faults is low (less than 60%)

The recently developed method of inputting a resistor and injecting a characteristic current signal into the system has significantly improved the success rate, but the investment is large, the safety is poor, and it is not suitable for frequent instantaneous ground faults

The transient current generated at the moment of the fault has a large amplitude (up to hundreds of amperes) and is not affected by the arc suppression coil, which can solve the problem of low sensitivity of line selection and location. However, due to the lack of deep understanding of fault transients, the transient method was proposed early (First half-wave method) criterion is unreasonable and has not been successfully applied

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