CAJ | 학술논문

云广特高压直流孤岛运行时，送端电网短路比和有效惯性常数显著低于联网方式，承受扰动能力较弱。如果逆变侧交流系统发生接地故障导致逆变站换相失败，直流电压和直流功率将大幅降低，引起送端孤岛系统过电压和频率升高。利用 PSCAD/EMTDC 电磁仿真软件，针对云广直流孤岛系统两种典型运行方式，研究了逆变侧交流系统故障对送端孤岛系统的影响。仿真结果表明：逆变侧交流系统故障引起的直流换相失败持续时间越长，整流侧交流系统短路比和有效惯性常数越小，送端孤岛系统受故障影响越严重；云广直流在两种典型孤岛运行方式下，逆变侧交流系统发生故障时，送端孤岛系统都能保持暂态稳定。
운엄특고압직류고도운행시，송단전망단로비화유효관성상수현저저우련망방식，승수우동능력교약。여과역변측교류계통발생접지고장도치역변참환상실패，직류전압화직류공솔장대폭강저，인기송단고도계통과전압화빈솔승고。이용 PSCAD/EMTDC 전자방진연건，침대운엄직류고도계통량충전형운행방식，연구료역변측교류계통고장대송단고도계통적영향。방진결과표명：역변측교류계통고장인기적직류환상실패지속시간월장，정류측교류계통단로비화유효관성상수월소，송단고도계통수고장영향월엄중；운엄직류재량충전형고도운행방식하，역변측교류계통발생고장시，송단고도계통도능보지잠태은정。
Short circuit ratio and effective inertia constant of the sending end grid under island operation mode of Yunnan-Guangdong ultrahigh voltage direct current(UVDC)project is notably lower than that under networking mode which means weak ability to bear turbulence. If commutation of the inverter station fails caused by grounding fault of alternative current (AC)system at the inverter side ,DC voltage and DC power may substantially reduce and cause overvoltage and frequency of the island system at sending end rise. In allusion two typical running modes of Yunnan-Guangdong UVDC island system, PSCAD/EMTDC electromagnetic simulation software was used for studying affect on the island system at sending end by AC system fault at the inverter side. The simulation results indicate that duration time of DC commutation failure is longer caused by AC system fault at the inverter side,short circuit ratio and effective inertia constant at the rectification side is smaller and affect on island system at sending end by the fault is more serious. In addition,under these two typical island op-eration modes,when the AC system at inverter side develops a fault,island system at sending end could still keep transient stability.