Identification and judgment method for switching into fault protection

Abstract

The invention discloses an identification and judgment method for switching into fault protection. A Prony analysis method is used for current waveform fitting and acquiring frequency, amplitude, attenuation factor and phase characteristic values of current components, criteria of switching into line fault protection are proposed by the aid of frequency, amplitude, attenuation factor and phase characteristic value parameters, and frequency domain characteristics of signals are identified. By the aid of a large number of simulation experiments, current waveforms of line no-load switching-in, single-phase fault and three-phase fault lines with fault distances of 10km, 50km, 90km, 100km, 200km, 300km and 400km are simulated respectively and fitted by the Prony analysis method, and frequencies, amplitudes, attenuation factors and phases of the current components are extracted. The criteria of switching into line fault protection are proposed by the parameters, and simulation results prove accuracy and reliability of the criteria.

Description

technical field [0001] The invention belongs to the technical field of electric power systems, and in particular relates to a method for identifying and judging switching on for fault protection. Background technique [0002] With the rapid development of the power system, more and more large-capacity units and ultra-high voltage transmission lines are widely used in the power system. If the action time of relay protection can be reduced, it will not only improve the stability of the system, but also increase the transmission capacity of the transmission line. For this reason, higher requirements are put forward for relay protection, and relay protection equipment is required to be able to remove faults reliably and quickly, otherwise, the power system will lose synchronization due to oscillation, resulting in unimaginable consequences. The traditional relay protection principle is based on the power frequency electrical quantity, and the useful information generated by the...

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Problems solved by technology

[0003] Generally speaking, the problems of the three methods of closing and fault protection based on the traveling wave time-domain characteristics of the closing operation in the line mainly include the following three aspects: First, due to the influence of measurement errors and other factors, the It is difficult to identify faults at the end of the line based on the principle of closing and fault protection; secondly, the identification criterion based on the polarity relationship of traveling waves must be based on the number of outgoing lines at the opposite end of the line, and the corresponding protection components must be selected in actual use, resulting in cost The third is that for the problem of three-phase closing in different phases, due to the difficulty in grasping the time difference of the three-phase closing and the use of discrete methods, it is easy to cause distortion of the fault acquisition signal

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