A method and device for single-phase ground fault line selection in small current systems based on distribution automation data

Abstract

The invention discloses a distribution automation data-based single-phase ground fault line selecting method and device for a small-current system. The distribution automation data-based single-phaseground fault line selecting method comprises the following steps: acquiring distribution automation data, and extracting the fault characteristic quantity of each distribution automation terminal; according to the fault characteristic quantity of each distribution automation terminal, constructing a fault measure membership function and a weight coefficient function of each distribution automationterminal; based on the fault measure membership function and the weight coefficient function of each distribution automation terminal, constructing a line fault membership function; calculating optimal values of line fault membership function parameters by a genetic algorithm, calculating the line fault membership of each line, judging whether a line has a fault according to the line fault membership of each line, and selecting a fault line. The distribution automation data-based single-phase ground fault line selecting method and device improve the fault line selecting accuracy, are applicable to a neutral ungrounded system and an arc suppression coil grounded system, and can identify various grounding conditions such as high-resistance grounding, arc grounding, intermittent grounding and instantaneous grounding.

Description

technical field [0001] The invention relates to the field of distribution network fault line selection, in particular to a method and device for single-phase ground fault line selection in a small current system based on distribution automation data. Background technique [0002] Improving the stability of the power system and improving the quality of power supply have always been the basic tasks of the power sector. The distribution network is the end of the power transmission channel, which is directly related to the power consumption of the users. The failure of the distribution network will directly cause the quality of the user's power to be reduced, and in severe cases, it will cause a power outage, endangering the safe and stable operation of the power system. According to statistics, 95% of the power outages suffered by users across the country are caused by distribution network faults, and the vast majority of distribution network faults are single-phase ground faul...

AI Technical Summary

Problems solved by technology

Among them, the line selection method based on the characteristics of a single fault selects the line by extracting the characteristic quantity that can reflect the difference between the faulty line and the sound line from the zero-sequence current of the line. This method directly faces the problem of small fault current, which affects the precision of transformer The degree of dependence is high, the accuracy cannot be guaranteed, and it is greatly affected by the neutral point grounding method and fault conditions

The line selection method based on multiple fault characteristics (comprehensive method) combines multiple single line selection methods for line selection. This line selection method realizes the complementary advantages of different single line selection methods, but because each outgoing line only collects a set of data , so it is still greatly affected by the accuracy of the transformer, and the accuracy is limited

The line selection method not based on the fault characteristics injects special signals by injecting signals, grounding the neutral point through the neutral resistance instantaneously, changing the compensation degree of the arc suppression coil, etc., and determines the fault line through signal tracing. The disadvantage of this method is that it needs to install Set up expensive signal injection equipment, which will impact the power grid, affect the stability of the distribution network, and cannot identify instantaneous ground faults

The problem of line selection for single-phase ground faults in small current systems has not been well resolved

The distribution master station communicates with the distribution automation terminal through the communication channel to obtain a large amount of fault-related information, which is not used in the current fault line selection method

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