Sequential action method of zero-sequence inverse time overcurrent protection for double-circuit lines on the same pole

Abstract

The invention discloses a same-tower double-circuit-line inside oriented zero sequence inverse time limit overcurrent protection sequent action method. The method includes: when one line of a double-circuit line is in a failure and a circuit breaker at the opposite end of the failed line trips, if zero-sequence power directions detected by protection on two lines at the current end are opposite, in other words, a zero-sequence power direction element on the failed line is judged as forward direction while a zero-sequence power direction element on a non-failed line is judged as reverse direction, judging as a failure inside an area and quickly tripping protection at the current end of the failed line, in other words, enabling protection at two ends of the failed line to realize protection acceleration by means of relay action so as to shorten action time of protection when zero-sequence current is low at an overcurrent protection position. The method has the advantages that by the method, zero-sequence inverse time limit overcurrent protection can be ensured to be quickly and reliably cut off by means of sequent action no matter where failures occur inside the double-circuit line.

Description

technical field [0001] The invention relates to the field of relay protection of power systems, in particular to a sequential action acceleration method for zero-sequence inverse time-limit overcurrent protection of a transmission network inside a double-circuit line on the same pole. Background technique [0002] Zero-sequence inverse time overcurrent protection has the unique advantage of inverse time limit, that is, the current flowing through the protection installation is inversely proportional to the protection action time, so it can obtain higher sensitivity when used as backup protection, and its application in high-voltage power grids is also increasing. widely. When a ground fault occurs in the power system, the zero-sequence equivalent power supply is located at the fault point. The farther the distance from the fault point is, the smaller the zero-sequence current flows. Therefore, in general, the zero-sequence inverse time overcurrent protection can be based on ...

AI Technical Summary

Problems solved by technology

Although the above scheme can adjust the action time of the protection according to the actual situation; however, this method requires the use of wide-area information, which is difficult to implement and high in cost, and it is difficult to popularize and apply it in the actual field

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