Power transmission line broken line locking method based on negative sequence network

Abstract

The invention discloses a power transmission line broken line locking method based on a negative sequence network; the method comprises the following steps: firstly collecting the power transmission line one side three phase currents and three phase voltages, and obtaining the opposite side three phase voltages through a signal channel; calculating the one side negative sequence current and negative sequence voltage according to obtained information, and calculating the opposite side negative sequence voltage; respectively calculating the negative sequence voltage difference value between two sides of the power transmission line and the negative sequence voltage drop reckoning value according to said data when the power transmission line is assumed to have no broken line fault; comparing the line two-side negative sequence voltage difference value and the negative sequence voltage drop reckoning value, and determining whether the power transmission line has a broken line or not. The method is not affected by multi-loop mutual inductances, thus improving the determination result accuracy, and enabling relay protection to selectively cut off the broken line fault in a heavy current grounding system.

Description

technical field [0001] The invention belongs to the field of relay protection of electric power systems, and in particular relates to a method for locking a broken transmission line based on a negative sequence network. Background technique [0002] In the large current grounding system, the single-phase or two-phase disconnection of the transmission line belongs to the phase failure state, which is different from the transverse fault formed by the short circuit, and belongs to the longitudinal fault. Although the disconnection fault is not as serious as the short-circuit fault, it also has a certain impact on the operation of the rotating electrical machine and the system and the relay protection. If the disconnection fault cannot be effectively removed, the line will be in a non-full-phase operation state, and the zero-sequence and negative-sequence currents that appear may cause the relay protection of the power system to leapfrog action, resulting in the expansion of the...

AI Technical Summary

Problems solved by technology

Its disadvantage is that in multi-circuit transmission lines, the zero-sequence component is greatly affected by the mutual inductance between lines, which easily affects the discrimination results

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