CAJ | 학술논문

为提高基于电压源换流器的高压直流输电系统的故障穿越能力及故障后对交流系统电压的快速支撑作用,在分析VSC_HVDC交流系统侧发生故障时系统暂态特性的基础上,提出基于故障分量补偿的优化控制策略.其中包括:正负序分量独立控制的双序电流内环控制器用于消除不对称故障引起的功率脉动;基于直流电压越限值补偿的有功功率控制器用于抑制故障期间的直流电压大幅波动;根据系统故障时故障电流的无功特性,由VSC外环无功功率控制器增大注入交流系统的无功电流指令,为交流系统提供快速的电压支撑.基于PSCAD/EMTDC环境的仿真结果证明,提出的优化控制策略在VSC_HVDC交流系统故障时能够有效地消除直流系统的二次脉动、抑制直流电压的骤变及提高交流系统的电压稳定性.
위제고기우전압원환류기적고압직류수전계통적고장천월능력급고장후대교류계통전압적쾌속지탱작용,재분석VSC_HVDC교류계통측발생고장시계통잠태특성적기출상,제출기우고장분량보상적우화공제책략.기중포괄:정부서분량독립공제적쌍서전류내배공제기용우소제불대칭고장인기적공솔맥동;기우직류전압월한치보상적유공공솔공제기용우억제고장기간적직류전압대폭파동;근거계통고장시고장전류적무공특성,유VSC외배무공공솔공제기증대주입교류계통적무공전류지령,위교류계통제공쾌속적전압지탱.기우PSCAD/EMTDC배경적방진결과증명,제출적우화공제책략재VSC_HVDC교류계통고장시능구유효지소제직류계통적이차맥동、억제직류전압적취변급제고교류계통적전압은정성.
To improve the ability of VSC_HVDC’s passing through faults and supporting AC system voltage quickly when AC fault occurs, this paper firstly analyzes the transient characteristic of VSC_HVDC system during AC grid fault. And then the corresponding optimal control strategies of VSC_HVDC based on fault components are proposed. They are as follows: the double-sequence inner loop current controller, which controls positive and negative sequence components independently, can eliminate power fluctuation caused by AC grid asymmetric faults; the outer loop active power controller based on DC voltage overriding compensation can suppress the great fluctuation of DC voltage; according to the reactive property of fault current during AC grid fault, the outer loop reactive power controller increases reactive current into the AC system to provide quick voltage support. The simulation results from the simulation software PSCAD/EMTDC prove that the proposed controller can validly get rid of the second harmonic of DC system, suppress the swift change of DC voltage, and improve AC voltage stability.