城区电网直流互联系统交流短路后电能质量优化策略  

Power quality optimization strategy after AC short circuit in DC interconnection system of urban power grid

作　　者：伍双喜 刘洋 朱誉 何宏亮 肖晃庆 杨苹[2] WU Shuangxi;LIU Yang;ZHU Yu;HE Hongliang;XIAO Huangqing;YANG Ping(Electric Power Dispatching Control Center of Guangdong Power Grid Co.,Ltd.,Guangzhou 510600,China;School of Electric Power Engineering,South China University of Technology,Guangzhou 510641,China)

机构地区：[1]广东电网有限责任公司电力调度控制中心,广东广州510600 [2]华南理工大学电力学院,广东广州510641

出　　处：《供用电》2023年第10期55-62,共8页Distribution & Utilization

基　　金：中国南方电网有限责任公司科技项目(GDKJXM20220335)。

摘　　要：为了提高城市输电走廊容量,增强城市电网灵活性,在难以对原有交流电网进行进一步扩建改造的前提下,将交流线路转换为直流线路可能是一种可行方案。为了促进城市中直流系统的改造,首先提出了城区负荷直流互联改造方案;接着针对直流系统中普遍存在的逆变器短路故障后过电压问题进行了理论分析,阐明了过电压产生的控制学原理;然后为了解决逆变器短路故障后过电压问题,遏制故障后电能质量的恶化,提出了过电压抑制策略,对逆变器内部PI环节进行控制,以期实现抑制过电压、优化电能质量的目的;最后结合实际电力系统中一处小型配电网的数据,建立了直流-交流互联系统模型进行仿真验证,仿真结果证实了过电压抑制策略的有效性。所提出的过电压抑制策略不仅可以降低短路故障切除后过电压水平,而且还可以缩短故障后恢复时间,优化电能质量,一定程度上可以促进直流系统的应用。In order to improve the capacity of urban transmission corridors and enhance the flexibility of urban power grids,on the premise that it is difficult to further expand the original AC grid,the conversion of AC grids to DC grids maybe a feasible scheme to improve the capacity of urban transmission corridors and enhance the flexibility of urban grids.In order to promote the transformation of DC grid in the city.Firstly the DC interconnection scheme of urban power grid is proposed.Secondly,the overvoltage caused by inverters after short circuit faults is analyzed theoretically,and the control principle of overvoltage generation is explained.Then in order to solve the overvoltage problem after the short-circuit fault and curb the deterioration of power quality,the overvoltage suppression strategy is proposed to control the PI inside the inverter.Finally,based on the data of a small distribution network in the actual grid,a DC-AC interconnection system model is established for simulation and verification,and the simulation results confirm the effectiveness of the overvoltage suppression strategy.The overvoltage suppression strategy proposed in this paper can not only reduce the overvoltage after short-circuit faults,but also shorten the recovery time after fault,optimize the power quality,and promote the application of DC system to a certain extent.

关 键 词：直流互联 逆变器 短路故障 过电压 电能质量 

分 类 号：TM71[电气工程—电力系统及自动化]