False synchronization differential protection sampling data rollback method and device of half-wavelength power transmission line

Abstract

The invention discloses a false synchronization differential protection sampling data rollback method and device of a half-wavelength power transmission line. The false synchronization differential protection sampling data rollback method comprises the steps of comparing passage delay time Tx with a power frequency period T; performing false synchronization differential impedance calculation on acurrent sampling point of sampling data rolled back to (Tx-T) moment of a side and a received sampling point of an opposite side if Tx is larger than T; performing false synchronization differential impedance calculation on the current sampling point of the side and the received sampling point of data rolled back to (T-Tx) moment of the opposite side if Tx is smaller than T; and unnecessarily performing rollback on the data if Tx is equal to T. By the false synchronization differential protection sampling data rollback method, the problem of longitudinal passage delay of false synchronizationdifferential protection in the half-wavelength power transmission line is solved in an emphasized way, false synchronization differential impedance protection calculation can be enabled to be performed by newest electrical quantity, and the protection action speed is increased.

Description

technical field [0001] The invention relates to the technical field of electric power system relay protection, in particular to a sampling data fallback method and device for false synchronous differential protection of a half-wavelength transmission line. Background technique [0002] Half-wavelength AC transmission technology refers to the ultra-long-distance AC transmission technology whose transmission distance is close to a power frequency half-wavelength (about 3000km at 50Hz). The fault characteristics are significantly different from those of conventional transmission lines, and the existing line protection based on centralized parameters is no longer applicable. . [0003] The voltage along the half-wavelength transmission line is nonlinear and non-monotonic. It is necessary to use the long-line equation to compensate the voltage and current, and use the compensation voltage and compensation current at the distance measurement point to construct synchronous differen...

AI Technical Summary

Problems solved by technology

[0006] The purpose of the present invention is to overcome the problem of long delay in the longitudinal connection channel of half-wavelength transmission line pseudo-synchronous differential protection in the prior art, and to provide a half-wavelength transmission line pseudo-synchronous differential protection sampling data fallback method. In the case of time delay, it not only meets the sampling data requirements of the false synchronous differential impedance protection, but also ensures that both sides are calculated using the latest electrical quantities, improving the protection action speed

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