Flexible DC power transmission overhead line fault rapid determining method without setting threshold

Abstract

The invention relates to a flexible DC power transmission overhead line fault rapid determining method without setting a threshold. The method is characterized in that single-end travelling wave signals which are rapidly spread in a power transmission line during a fault are employed as original data for fault determination, the rapidness and the economic benefits are excellent; and mold maximum change conditions after single-end transient voltage travelling wave signals and single-end transient current travelling wave signals are subjected to wavelet multiple dimensioned analysis are taken as a criterion for determining whether a system generates a fault and whether the fault is a zone inside fault or a zone outside fault, and at the same time, amplitude of forward traveling waves and backward travelling waves of the single-end transient voltage travelling wave signals is taken as a fault direction criterion. The method is simple in principle, is effective, is easy to implement, does not require setting and arranging a threshold value, avoids determining errors and protection maloperation which are easily caused by manual arrangement and setting of the threshold through reliance on engineering experience in a conventional method, and the reliability is higher compared to other methods. Finally, through combination with wavelet feature entropy identification fault types, wrong determination is effectively prevented, and the fault identification accuracy is effectively improved.

Description

technical field [0001] The invention relates to the field of high-voltage direct current transmission, in particular to a method for quickly judging faults of overhead lines of flexible direct current transmission without threshold value setting. Background technique [0002] Compared with traditional AC transmission, high voltage direct current (HVDC) has significant advantages in high-voltage, long-distance, and large-capacity transmission of electric energy, while flexible DC transmission based on power electronics technology (voltage source converter based high voltage direct current (VSC-HVDC) has achieved vigorous development in large power grid interconnection and point-to-point power transmission due to its advantages of flexible power control and no commutation failure. The grid connection and consumption of new energy provides a solution. However, the isolation and removal of DC short-circuit faults still needs to be solved urgently, and the high-voltage DC circui...

AI Technical Summary

Problems solved by technology

However, the problem of isolation and removal of DC short-circuit faults still needs to be solved urgently, and the high-voltage DC circuit breaker with fast breaking short-circuit current restricts the development of flexible DC transmission network

At present, researchers at home and abroad mostly focus on the implementation of the circuit breaker itself, but there is almost no research on fault detection and identification, which is an important part of DC fault current breaking.

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