摘要
针对多端直流(MTDC)电网中限流电抗器的配置问题,提出了一种通用的优化设计新方案。该方案以系统配置的限流电感总和最小为优化目标,综合考虑了直流断路器、换流站闭锁和保护需求的约束条件,采用优化算法确定了限流电抗器的全局最优配置。该设计方案减小了限流电感给系统带来的不利影响,并能够保证系统在故障穿越期间能够连续、可靠地运行。由于在优化过程中采用了短路电流近似计算模型,从而大大提高了优化效率。最后,基于PSCAD/EMTDC仿真平台搭建三端模块化多电平换流器(MMC)型直流电网,仿真结果验证了所提出方法的有效性。
A general design method is proposed for the optimization of current limiting reactor in the multi-terminal DC(MTDC)power grid.The minimization of the total current limiting reactors installed in the system is determined as the design objective,and the constraints of DC circuit breaker,converter blocking and protection requirements are considered.The optimization algorithm is used to determine the optimal allocation of current limiting reactors.The proposed design method can reduce the adverse impacts of large reactors,and enables the continuous and reliable operation during fault ride-through.Furthermore,since the approximate model of fault currents calculation for MTDC is used,the calculation efficiency is improved greatly.At last,a three-terminal modular multi-level converter(MMC)based DC power grid is modeled based on PSCAD/EMTDC simulation platform,and the simulation results verify the effectiveness of the proposed method.
引文
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