高比例新能源接入下送端电网直流闭锁过电压分析与抑制策略

近年来，以风电和光伏为主的可再生能源发电技术发展迅速。考虑到可再生能源资源富集区域和重负荷区域之间存在空间上的分布差异，高压直流输电被证明是一种能够有效将电力进行远距离传输以提升可再生能源消纳的技术。高压直流输电系统的直流闭锁故障，特别是直流双极闭锁故障，会导致送受端交流电网中产生过电压浪涌，进而可能导致发电机脱网运行。文中建立了直流闭锁故障下送端交流电网中过电压的数学模型，分析了可再生能源发电设备的无功功率对直流闭锁下电网过电压的影响，进而以送端电网的无功功率裕度最大为目标提出了一种最优有功出力分配策略。基于Matlab/Simulink,设计了一个案例来验证所提出的最优有功出力分配策略减少直流闭锁下电网过电压的有效性。

Overvoltage Analysis and Suppression Strategy of Sending AC GridSub-module Faults in with High Renewable Energy Penetration under DC Blocking

Renewable energy power generation technologies dominated by wind power and photovoltaics have grown rapidly in recent years. Considering the spatial distance between renewable energy-rich areas and heavy loaded areas, high voltage direct current (HVDC) transmission technology is a method that can efficiently transmit power to improve renewable energy consumption. Converter blocking of HVDC transmission system, especially DC bipolar blocking, can cause overvoltage surges in AC grid, which can force the renewable generators to be off-grid. The mathematical model of overvoltage of sending AC grid under DC blocking is established. The influence of reactive power of renewable energy generators on overvoltage in AC grid under DC blocking is analyzed. An optimal active power distribution strategy is proposed to increase the overall reactive power margin of sending AC grid to reduce overvoltage surges. A case is designed based on Matlab/Simulink to verify the proposed optimal active power distribution strategy.