Power distribution network cable-line commingle line fault route selection anastomosing method using extension theory

Abstract

The invention relates to a fault line selection fusion method of a power distribution network cable-line mixing line which utilizes an extensive theory, and belongs to the electric power system relaying protection technology field. The application of a distribution network cable-line mixing line is increased in cities, a cable in a unit length has larger capacitance for the earth than a trolly wire, frequency dependent character of a cable parameter is serious, and a voltage current fault transient state component is more distinct when the cable-line mixing line is connected with the ground ina single phase way. Perceptual decay direct current component characteristic of each feeding outgoing line fault zero-sequence current is fused with a disintegrating and integrating relative coefficient of a transient component small waving bag through utilizing the extensive theory. Possible fault line assembly, fault characteristic assembly and an amount domain which is set by the characteristic are used as three factors for the extendable merging matter, and the decay direct current component and the small waving bag disintegrating and integrating relative coefficient are used as the characteristic assembly. A weight function can be objectively confirmed according to the size of a fault close angle, a fault confident degree of each line can be calculated through utilizing the extensivecorrelation function, and the fault outgoing line is judged according to the confident degree. A great number of artificial results indicate that the line chosen by the method is accurate and reliable.

Description

technical field [0001] The invention relates to a fault line selection fusion method of a distribution network cable-line hybrid line using extension theory, and belongs to the technical field of electric power system relay protection. Background technique [0002] With the rapid development of the urban power grid, the laying of cables can not only increase the transmission capacity of the line, reduce the size of the outgoing line of the substation, but also reduce the pressure on the line channel, improve the channel utilization rate, and simplify the network connection. Therefore, the existing overhead lines are gradually Into the ground, the proportion of cable lines in the power grid is increasing, and there are more and more cable-line hybrid lines [1，2] . Due to the relatively large ground capacitance of the cable and the serious frequency-dependent characteristics of the cable parameters, the transient process of the cable line is obvious after the fault occurs. D...

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Problems solved by technology

e) Zero-sequence instantaneous power phase inversion problem

(4) Various methods have limitations, and it is difficult to find a universally applicable method, and it is necessary to solve the problem of effective fusion of multiple line selection criteria

The fusion method based on the above two theories is mainly determined by subjective experience values ​​in the processing of problems such as the turning point of the distribution function and the determination of the membership function, which is difficult to adapt to the uncertain fault reality, and these fusion line selection methods have no Solve the problem of difficult line selection when the fault closing angle of the resonant grounding system is small

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