Method for preventing misoperation of zero-sequence direction components without influence of weak feedback

Abstract

The invention discloses a method for preventing misoperation of zero-sequence direction components without influence of weak feedback. The method includes (1), acquiring phase currents and phase voltages of line protection mounting positions; (2), extracting sudden change quantities of the phase currents and the phase voltages; (3), judging whether algorithms for preventing misoperation need to be started or not according to starting criteria for the algorithms for preventing misoperation, and carrying out a step (4) if the algorithms need to be started; (4), computing current error coefficients and voltage error coefficients of two ends of each line, judging whether the lines are perfect lines or not according to comprehensive error coefficient criteria, locking the zero-sequence direction components of the lines if the lines are the perfect lines. The zero-sequence direction components of the lines are not locked if the lines are not the perfect lines. Compared with the prior art, the method has the advantages that the perfect lines and the fault lines can be identified only by the aid of single-end electric quantity information of single-circuit lines; the error coefficients can be computed in time domains, and accordingly the method is low in computational complexity and high in judgment speed and sensitivity; the method is applicable to non-weak-feedback systems and weak feedback systems, and correct actions of the zero-sequence direction components always can be guaranteed.

Description

【Technical field】 [0001] The invention relates to the field of relay protection for power system transmission lines, in particular to a method for preventing maloperation of zero-sequence directional elements. 【Background technique】 [0002] Multi-circuit lines on the same tower can effectively alleviate the shortage of land resources in power grid construction and increase the transmission capacity of unit corridors. Long-distance transmission lines erected in parallel also widely exist in the power grid. Due to the mutual inductance between the circuits, the zero-sequence directional elements applied to single-circuit lines cannot be simply applied to multi-circuit lines on the same tower and long lines erected in parallel, and the protection principle needs to be modified accordingly. [0003] The mutual inductance between the loops is dominated by zero-sequence mutual inductance. When an asymmetrical short-circuit ground fault occurs in any of the loops, the zero-sequen...

AI Technical Summary

Problems solved by technology

[0009] The purpose of the present invention is to provide a zero-sequence directional element anti-misoperation method that is not affected by weak feed to solve the problem of misoperation of traditional zero-sequence directional elements; Occurrence of misoperation of zero-sequence directional components

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