Abstract：For modular multi-level converter based high voltage direct current (MMC-HVDC) grid using overhead lines, the incidence of DC side grounding short circuit fault is high, which seriously endangers the safety of the power grid. Among all kinds of influencing factors, the grounding mode has an obvious influence on the evolution of fault current. In this paper, an optimization method of grounding parameters based on transient energy flow (TEF) analysis is proposed from the point of view of perspective of macroscopic energy transfer and dissipation of the system. The effects of grounding resistance, reactance parameters and grounding location on the evolution of DC short circuit fault current in MMC-HVDC grid are analyzed. In this method, the TEF suppression rate and suppression efficiency are taken as the optimization objectives, the grounding impedance parameters and the grounding location in the DC grid are taken as the optimization variables. Meanwhile, the influence of neutral line reactance and fault point are considered. In this paper, an example of four-terminal bipolar MMC-HVDC grid under DC pole-to-ground fault (PTGF) condition is selected and a simulation model is built based on PSCAD/EMTDC for analysis and optimization. The simulation results show that the parameter optimization method can effectively guide the design of grounding parameters, restrain DC fault current and overvoltage of healthy pole.
茆美琴, 程德健, 袁敏, 陆辉, 施永. 基于暂态能量流的模块化多电平高压直流电网接地优化配置[J]. 电工技术学报, 2022, 37(3): 739-749.
Mao Meiqin, Cheng Dejian, Yuan Min, Lu Hui, Shi Yong. Optimal Allocation of Grounding System in High Voltage Direct Current Grid with Modular Multi-Level Converters Based on Transient Energy Flow. Transactions of China Electrotechnical Society, 2022, 37(3): 739-749.
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2022, Vol. 37 
