Longitudinal traveling wave protection method applicable to hybrid direct current power transmission line

Abstract

The invention discloses a longitudinal traveling wave protection method applicable to a hybrid direct current power transmission line. The method comprises the steps as follows: an LCC end protectionunit and a VSC end protection unit separately acquire positive and negative high frequency voltage traveling wave signals and positive and negative high frequency current traveling wave signals of corresponding ends on the power transmission line, an LCC end faulted pole and a VSC end faulted pole are recognized according to the positive high frequency current traveling wave signal and negative high frequency current traveling wave signal of the corresponding end and known faulted poles; a fault direction corresponding to the LCC end faulted pole and the fault direction corresponding to the VSC end faulted pole are recognized; if the fault detections of the LCC end and the VSC end are forward, the fault type is determined to be the internal fault, and otherwise, the fault type is determined to be the external fault; and corresponding protection is executed according to the determined fault type.

Description

technical field [0001] The invention belongs to the field of electric power technology, in particular relates to a protection method for a power system, and more specifically relates to a longitudinal traveling wave protection method suitable for a hybrid direct current transmission line. Background technique [0002] With the gradual increase in the scale of the power system, a large number of large-capacity AC-DC hybrid systems with the characteristics of long transmission distance, large transmission capacity, and high transmission efficiency have been constructed. LCC-HVDC system, as a current source HVDC transmission system, has large transmission capacity and low transmission loss, but there is a risk of commutation failure when it is applied to an inverter station. As a voltage source HVDC system, the VSC-HVDC system can transmit power to passive systems without the risk of commutation failure, and can achieve certain power flow control, but its transmission capacity ...

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to provide a longitudinal traveling wave protection method suitable for hybrid direct current transmission lines, which solves the technical problems of poor fault identification reliability and easy misoperation of protection existing in the prior art

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