含大规模光伏并网的弱送端系统的电压稳定性

随着新能源电力的蓬勃发展，中国西北地区的高压直流送端系统逐渐呈现出新能源占比高、交流网架薄弱、转动惯量小等特征，由此引发的弱送端系统电压稳定性问题不容忽视。首先，从含大规模光伏并网的弱送端换流母线静态电压调节灵敏度出发，推导了影响换流母线电压稳定性的因素。进而设计了光伏并网临界容量的计算流程，为光伏场站选址定容提供依据。提出了送端综合短路比指标（sending-end comprehensive short circuit ratio，SCSCR），用来描述含大规模光伏并网的弱送端交流系统的支撑强度。比较了SCSCR、短路比、有效短路比等指标，结果表明SCSCR与弱送端系统静态电压稳定性更具相关性。SCSCR指标可以简化弱送端系统电压稳定性的分析过程，指导高比例新能源外送系统的电源组织与拓扑设计。

Voltage Stability of Weak Sending-end System with Large-Scale Grid-connected Photovoltaic Power Plants

With the rapid development of new energy power, the HVDC sending-end system in the northwest of China gradually shows the characteristics of high penetration of new energy, weak AC grid and small rotational inertia, and the voltage stability problems of the weak sending-end system caused by them cannot be ignored. Firstly, based on the static voltage sensitivity of the converter bus with large-scale grid-connected photovoltaic power plants at the sending end, the factors affecting the voltage stability of the converter bus are derived. Furthermore, a calculation process for photovoltaic grid-connected critical capacity is designed to provide a basis for site and capacity selection of PV plants. A sending-end comprehensive short circuit ratio (SCSCR) index is proposed to describe the support strength of AC system at the weak sending-end with large-scale grid-connected photovoltaic power plants. The comparison of SCSCR, SCR and ESCR shows that SCSCR is more relevant to the static voltage stability of the weak sending-end system. The SCSCR index can simplify the analytic process of voltage stability of weak sending-end system, and guide the power source organization and topology design of outbound delivery system with high penetration of new energy.