Hybrid direct-current transmission line traveling wave protection method based on S transformation

Abstract

The invention discloses a hybrid direct-current transmission line traveling wave protection method based on S transformation. The method includes: respectively acquiring voltage traveling wave data and current traveling wave data on electric transmission lines at two ends, and respectively acquiring 1-mode voltage traveling wave data and 1-mode current traveling wave data at each end based on thevoltage traveling wave data and the current traveling wave data; performing S transformation on the 1-mode voltage traveling wave data and the 1-mode current traveling wave data of each end to obtainan S transformation matrix corresponding to each end; acquiring an amplitude-frequency traveling wave matrix corresponding to each end according to the S transformation matrix of each end, and calculating amplitude-frequency traveling wave energy corresponding to each end according to the amplitude-frequency traveling wave matrix of each end; identifying the fault direction of each end according to the amplitude-frequency traveling wave energy of each end; identifying the fault type according to the fault directions of two ends; and executing corresponding protection according to the identified fault type. By applying the method, the reliability of the hybrid direct-current transmission line traveling wave protection can be improved.

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 an S-transform-based hybrid direct current transmission line traveling wave protection method. Background technique [0002] The high-voltage direct current transmission system LCC-HVDC (line commutated converter based HVDC) based on the principle of line current commutation has long transmission distance, large transmission capacity and high transmission efficiency. However, the LCC-HVDC inverter station is prone to commutation failure, which leads to transmission reliability problems. MMC-HVDC (modular multilevel converter based HVDC), a flexible HVDC transmission system based on the principle of modular multilevel, has no risk of commutation failure and can achieve certain power flow control. However, the transmission capacity of the MMC-HVDC system is small and the construction cost is h...

AI Technical Summary

Problems solved by technology

[0004] In order to solve the problem of poor reliability and easy misoperation of the traveling wave protection method of the LCC-MMC-HVDC hybrid direct current transmission line in the prior art, the present invention proposes a traveling

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