Traveling wave direction longitudinal protection method suitable for mmc-hvdc transmission lines

Abstract

The invention discloses a traveling wave direction pilot protection method suitable for a MMC-HVDC power transmission line. The method comprises: a rectification side protection unit and an inversionside protection unit respectively obtaining anode and cathode voltage traveling wave signals and anode and cathode current traveling wave signals on power transmission lines of ends where the rectification side protection unit and the inversion side protection unit are located, and determining anode and cathode instantaneous traveling wave power according to the voltage traveling wave signals andthe current traveling wave signals; identifying a rectification side fault pole and an inversion side fault pole according to the positive pole instantaneous traveling wave power and negative pole instantaneous traveling wave power of the end and known fault pole identification criterion; identifying a fault direction corresponding to the fault pole of a rectification side and a fault direction corresponding to the fault pole of an inversion side; if the fault directions of the two sides are both forward directions, determining that a fault type is an internal fault; otherwise, determining thefault type to be an external fault; and executing corresponding protection according to the determined fault type. By applying the method and the device, technical problems 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 MMC-HVDC transmission lines. Background technique [0002] The modular multilevel converter based high voltage direct current (MMC-HVDC) technology has many advantages: Compared with the traditional AC transmission system, it can realize flexible power flow control and at the same time give Weak AC system or even passive system power supply; compared with the traditional high-voltage DC transmission system, its inverter station will not have the problem of commutation failure. Therefore, in the power system construction, the MMC-HVDC power transmission system has been widely used. [0003] At present, the main protection of MMC-HVDC transmission lines still adopts the traditional traveling wave protection method based on ...

AI Technical Summary

Problems solved by technology

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

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