An Optimized Coordination Strategy between Line Main Protection and Hybrid DC Breakers for VSC-Based DC Grids Using Overhead Transmission Lines

Energies

Xiangyu Pei¹  Rong Jia²  Xiangyu Zheng²  Linling Gong³  Guangru Zhang⁴ 

[1] China Electric Power Research Institute, Haidian District, Beijing 100192, China;Institute of Water Resources and Hydro-electric Engineering, Xi’an University of Technology, Xi’an 710048, China;Lanzhou Petrochemical College of Vocational Technology, Lanzhou 730070, China;State Grid GanSu Electric Power Research Institution, Lanzhou 730070, China;

关键词: coordination strategy;    VSC-based DC grid;    overhead transmission line;    line main protection;    DC breaker;   

DOI  :  10.3390/en12081462

来源: DOAJ

【 摘 要 】

Compared with alternating current (AC) power grids, the voltage-sourced converter (VSC)-based direct current (DC) grid is a system characterized by “low damping„, as a result, once there is a short-circuit fault on the DC transmission line, the fault current will rise more sharply and the influence range will be much wider within the same time scale. Moreover the phenomenon that a local fault causes a whole power grid outage is more likely to occur. Overhead transmission lines (OHLs) have been regarded as the mainstream form of power transmission in future high-voltage, large-capacity and long-distance VSC-based DC grids. However, the application of overhead transmission lines will inevitably lead to a great increase in the probability of DC line failure. Therefore, research on how to isolate the DC fault line quickly is of great significance. Based on the technology route for fault line isolation using DC breakers, on the basis of in-depth analysis of traditional coordination strategy, an optimized coordination strategy between line main protection and a hybrid DC breaker for VSC-based DC grids using overhead transmission lines is proposed in this paper, which takes the start-up output signal of line main protection as the pre-operation instruction of the corresponding hybrid DC breaker. As a result, the risks of blockage of the modular multilevel converter (MMC) closer to the fault position and of damage to power electronic devices in main equipment can be reduced effectively. Finally, the proposed coordination strategy was verified and analyzed through simulation.

【 授权许可】

Unknown