新能源柔直汇集系统的分层多目标安全裕度优化  

Hierarchical Multi-objective Safety Margin Optimization of Renewable Energy Island Collecting Delivery System by VSC-HVDC

作　　者：黎上强 乔颖[1] 徐曼 吴林林 鲁宗相[1] 鲜文渊 LI Shangqiang;QIAO Ying;XU Man;WU Linlin;LU Zongxiang;XIAN Wenyuan(State Key Lab of Control and Simulation of Power Systems and Generation Equipments(Dept.of Electrical Engineering,Tsinghua University),Haidian District,Beijing 100084,China;State Grid Jibei Electric Power Research Institute(North China Electric Power Research Institute Co.,Ltd.),Xicheng District,Beijing 100045,China)

机构地区：[1]电力系统及发电设备控制和仿真国家重点实验室(清华大学电机系),北京市海淀区100084 [2]国网冀北电力有限公司电力科学研究院(华北电力科学研究院有限责任公司),北京市西城区100045

出　　处：《电网技术》2020年第12期4513-4520,共8页Power System Technology

基　　金：国家电网有限公司科技项目(SGJBDK00ZDJS1800022)。

摘　　要：新能源大规模接入和直流电网是未来电网的2个热点。新能源发电交流汇集后接入定电压/频率模式下的电压源型(voltage sourced converter,VSC)换流站,构成新能源孤岛柔直汇集送出系统。相较于纯交流送出模式,该系统的电压支撑由VSC换流站控制策略实现并与新能源交流汇集网络的无功电压控制相协调,可控性更高、适应性更好。然而,新能源的强随机波动性使换流站的安全裕度随工况而急剧变化,其优化控制成为影响系统安全的关键难题。提出"站–网"协调的多目标换流站安全裕度优化方法,以公共耦合点(point of common coupling,PCC)的电压作为层间交换变量,上层进行换流站无功电压安全裕度优化以确定PCC电压值,下层依据PCC电压值进行新能源汇集网络的经济优化,实现了多工况下考虑网损、无功电压安全等多重目标的安全裕度优化控制。最后基于某柔直电网新能源输送系统的仿真,验证了所提策略能够在各种工况下保证平稳的高安全裕度。1: Large-scale renewable generation integration and DC power grid are two hot subjects in the future power grid. The renewable generation cluster is connected to the voltage sourced converter(VSC) station, under the control mode of VF, forming a renewable energy island colleting delivery system based on High Voltage Direct Current with VSC(VSC-HVDC). Compared with the AC delivery mode, this mode has higher controllability and better adaptability, in which the voltage support is dominated by the control strategy of VSC station and coordinated with the reactive voltage control of the AC collecting network. However, the optimization of the safety margin of VSC station becomes a key problem affecting the system security because it may change rapidly with the working conditions caused by the strong fluctuation of the renewable energy. This paper proposes a multi-objective optimization method of safety margin for VSC station based on station-network coordination. The voltage of the point of common coupling(PCC) is used as the inter layer exchange variable. The voltage of PCC is determined by the reactive voltage safety margin optimization of VSC station in the upper layer, while the economic optimization of the renewable collecting network is achieved based on the voltage of PCC in the lower layer. In this way the optimization of safety margin is realized which satisfies the needs of multiple objectives, like network loss, reactive voltage safety and so on. Finally, the simulation verifies that the proposed optimization strategy can get a high and stable safety margin in different working conditions based on the renewable energy delivery system of an actual VSC-HVDC project.

关 键 词：新能源孤岛柔直汇集送出系统 VSC换流站 动态无功裕度 电压安全裕度 分层多目标优化 

分 类 号：TM721[电气工程—电力系统及自动化]