Single-ended Protection Scheme For VSC-HVDC Grids Based On High-Frequency Component Of Fault Current

Abstract

Accurate identification and location of faults on the DC side are technical difficulties to be solved urgently for the multi-terminal VSC-HVDC grids. Firstly, the characteristics of line boundary are analyzed, using the obvious difference of the current high-frequency transient energy during the internal and external faults to locate the fault. Secondly, the polarity difference of the transient voltage of the current-limiting reactor is used as the direction identification criterion for line protection. Considering the effect of different transition resistance and circuit breaker breaking process. The line protection is realized by single-terminal quantity, and the fault isolation is realized by coordination among circuit breakers. The simulation verifies that the proposed protection scheme can quickly and reliably identify different distances and different types of faults, meet the protection speed and reliability requirements, and have strong transition resistance and anti-interference capabilities.

Keywords

• multi-terminal vsc-hvdc grids
• wavelet transform
• hybrid dc circuit breaker
• fault identification
• coordinate protection