Circuit model-based single-phase earth fault section location method

Abstract

The invention provides a circuit model-based single-phase earth fault section location method, which comprises the following steps: in case of a single-phase earth fault at a certain position in a power distribution network, acquiring sampling values of a zero sequence voltage uM0 and a zero sequence current iM0 of the fault of a bus position (which is recorded as M end, and a next monitoring endaway from the M end by 1 is an N end) of a power supply end of the region according to data of a fault recording device; fitting the discrete sampling values of the zero sequence voltage uM0 and the zero sequence current iM0 by using the maquart method to acquire continuous time functions uM0(t) and iM0(t); calculating a zero sequence voltage uN0(t)c and a zero sequence current iN0(t)c of the nextmeasurement point N which is 1 away by using a distributed parameter circuit model; respectively comparing the calculated zero sequence voltage uN0(t)c and zero sequence current iN0(t)c of the N endwith a zero sequence voltage uN0(t) and a zero sequence current iN0(t)c which are obtained by sampling and fitting at the position N, and if the voltages and the currents are consistent, determining that the MN section is not a fault section, and continuously searching the next line; if the voltages and the currents are not consistent, determining that the MN section is a fault section. The methodcan locate a single-phase earth fault section on the basis of not increasing the hardware investment.

Description

technical field [0001] The invention belongs to the field of daily maintenance of electric power, and in particular relates to a criterion and a method for realizing the location of a single-phase ground fault section of a distribution network based on a line model. Background technique [0002] At present, most of the section location methods for distribution network faults are realized through the data acquisition devices installed on the lines. For single-phase ground fault, for the neutral point grounded by small resistance or neutral point ungrounded system, through the comparison of two adjacent zero-sequence currents on the line, it can be clearly judged whether the single-phase ground fault occurs in the two data between acquisition devices, so the above method is available. However, for the system where the neutral point is grounded through the arc-suppression coil, the weak and uncertain zero-sequence current makes it difficult to locate the single-phase ground fa...

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Problems solved by technology

However, for the system where the neutral point is grounded through the arc-suppression coil, the weak and uncertain zero-sequence current makes it difficult to locate the single-phase ground fault section. The method can make the characteristics of the single-phase ground fault between the two data acquisition devices obvious, and then realize the section location of the single-phase ground fault, but this kind of method requires additional professional equipment

At present, the zero-sequence transient power method, zero-sequence transient current amplitude method, zero-sequence current waveform correlation method, etc., which use the characteristics of electrical quantity changes during single-phase ground faults to realize the location of single-phase ground fault sections, are subject to many practical applications in the field. Due to the influence of various factors, it is still impossible to determine the location of the fault section of the distribution network with certainty. If there is strong interference, human auxiliary analysis is still required for judgment.

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