多直流协调的新能源送端地区暂态过电压抑制策略

针对直流闭锁故障导致的高比例新能源多直流送端系统暂态过电压问题，文中首先分析多直流间的交互影响机理，引入多馈出电压交互作用因子，揭示了直流闭锁导致其他健全直流近区域交流系统暂态过电压的根本原因。其次基于直流闭锁故障下调相机不同时间尺度的无功特性与整流侧换流母线电压的定量关系，在改进直流系统整流侧控制的前提下，于整流侧母线处投入调相机并以调相机暂态无功特性对其容量进行配置，降低了调相机所需投入容量。然后整合了调相机与整流器的无功调节能力，据此提出多直流、多无功设备协调配合的暂态过电压抑制策略。最后在PSCAD仿真平台中搭建两直流送端系统模型，验证了所提协调策略对暂态过电压的抑制效果以及调相机容量的配置效果。

Multi DC coordinated transient overvoltage suppression strategy for high proportion new energy sending terminal area

Aiming at the transient overvoltage problem of high proportion new energy multi direct current (DC) transmission system caused by DC blocking fault,the interaction mechanism between multiple DC lines is analyzed firstly and the multi-outfeed voltage infection factor is introduced,which reveals the fundamental reason of transient overvoltage of other sound DC near area alternating current (AC) systems caused by DC blocking. Secondly,based on the quantitative relationship between reactive power output of the synchronous condenser in different time scales and rectifier side commutation bus voltage and improved rectifier side control of DC system,the capacity of the synchronous condenser installed on the rectifier side bus is configured and the required investment capacity is reduced. Thirdly,based on the above strategy,integrating the reactive power regulation capability of the synchronous condenser and rectifier,a transient overvoltage suppression strategy with coordinated cooperation of multi DC and multi reactive power equipment is proposed. Finally,a double-circuit DC transmission system model is built in PSCAD simulation platform to verify the suppression effect of the proposed coordination strategy on transient overvoltage and the configuration effect of condenser capacity.