Traveling wave direction pilot protection method suitable for VSC-HVDC power transmission line

Abstract

The invention discloses a traveling wave direction pilot protection method suitable for a VSC-HVDC power transmission line. The method comprises: a rectification side protection unit and an inversionside protection unit respectively obtaining positive and negative original direct current voltage signals and positive and negative high-frequency current traveling wave signals on a power transmission line of an end where the rectification side protection unit and the inversion side protection unit are located; identifying a rectification side fault electrode and an inversion side fault electrodeaccording to the positive electrode high-frequency current traveling wave signal, the negative electrode high-frequency current traveling wave signal and known fault electrode identification criterion of the end where the rectification side fault electrode and the inversion side fault electrode are located; identifying a fault direction corresponding to the fault electrode at the rectification side and a fault direction corresponding to the fault electrode at the inversion side; if the fault directions of the two sides are both forward directions, determining that the fault type is an internal fault; otherwise, determining the fault type as an external fault; and executing corresponding protection according to the determined fault type. By applying the method and the device, the technicalproblems of poor fault identification reliability and easy misoperation of protection in the prior art can be solved.

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 traveling wave direction longitudinal protection method suitable for VSC-HVDC transmission lines. 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. As a voltage source type HVDC transmission system, the VSC-HVDC system can realize flexible power flow control, and can supply power to weak AC systems and even passive systems, and the inverter station does not have the risk of commutation failure. Therefore, VSC -HVDC power transmission system has been widely used, and it will also be an important direction for the development of HVDC. [0003] At present, the m...

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Problems solved by technology

[0004] The purpose of the present invention is to provide a traveling wave direction longitudinal protection method suitable for VSC-HVDC 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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