Application research on pilot protection method for multi‐terminal hybrid line‐commutated converter/modular multilever converter‐based high voltage DC system

Abstract

Abstract The multi‐terminal hybrid line commutated converter (LCC)/modular multilevel converter (MMC)‐based high voltage dc (HVDC) has been applied to solve the simultaneous commutation failure problem in East China. Here, the propagation of the travelling wave is characterised by transfer functions and the characteristic of the fault current travelling wave in the multi‐terminal hybrid LCC/MMC HVDC system is analysed. Then a directional pilot protection for the multi‐terminal hybrid LCC/MMC HVDC system is proposed. The proposed method is implemented to the designed HCM5000 dc control and protection device and verified in the Kun–Liu–Long three‐terminal hybrid LCC/MMC HVDC real‐time digital simulator (RTDS) test system. The test results show that the proposed method meets the engineering requirement of multi‐terminal hybrid LCC/MMC HVDC system for line protection.

Keywords

• d.c. transmission
• Power system protection