含电力电子变压器的交直流混合电网最优潮流  

Optimal Power Flow for Hybrid AC/DC Grid With Power Electronic Transformer

作　　者：耿琪 胡炎[1] 何建宗 周永言 赵伟 GENG Qi;HU Yan;HE Jianzong;ZHOU Yongyan;ZHAO Wei(Institute of Electronic Information and Electrical Engineering,Shanghai Jiao Tong University,Minhang District,Shanghai 200240,China;Dongguan Power Supply Bureau,Guangdong Power Grid Limited Liability Company Dongguan 523000,Guangdong Province,China;Electric Power Research Institute of Guangdong Power Grid Co.,Ltd.,Guangzhou 510080,Guangdong Province,China)

机构地区：[1]上海交通大学电子信息与电气工程学院,上海市闵行区200240 [2]广东电网有限责任公司东莞供电局,广东省东莞市523000 [3]广东电网有限责任公司电力科学研究院,广东省广州市510080

出　　处：《电网技术》2019年第9期3288-3296,共9页Power System Technology

基　　金：国家重点研发计划资助项目(2017YFB0903202)~~

摘　　要：电力电子技术的发展以及直流电源和直流负荷的应用,促使交流电网向交直流混合电网转变。传统交流电网最优潮流(OPF)问题可以确定电网的安全经济运行状态,非线性潮流方程的存在使得OPF问题属于非线性非凸优化问题的范畴。在融合电力电子变压器(PET)的交直流混合电网中,PET的运行约束进一步增加了交直流混合电网OPF问题的非凸性。将重点解决交直流混合电网OPF问题的非凸性。交直流混合电网OPF问题的目标函数为最小化发电成本以及线路和电力电子变压器的损耗,约束条件包括交直流电网中各节点功率平衡约束,电压幅值约束,各支路功率约束以及和电力电子变压器相关的运行约束。使用凸松弛技术将OPF问题转化为半定规划(SDP)问题,并推导得出零松弛间隙的充分条件,以获得全局最优解。在含PET的扩展IEEE 33测试系统上进行仿真,证明了零松弛间隙的充分条件适用于实际交直流混合电网,并且可以获得全局最优解。Development of power electronic technology and application of DC power and DC load promote transformation of AC power grid to hybrid AC/DC power grid.The optimal power flow(OPF)of traditional AC grid can determine the safe and economic operation state of the grid.Existence of nonlinear power flow equation makes the OPF problem belong to nonlinear and non-convex optimization category.In the hybrid AC/DC grids with power electronic transformers(PETs),the operational constraints of PETs further increase non-convexity.This paper focuses on addressing non-convexity of the OPF problem in hybrid grids.The objective function of the OPF problem in hybrid grids is to minimize generation cost and the loss of lines and power electronic transformers.The constraints include power balance constraints of each node in the hybrid grids,voltage amplitude constraints,power constraints of each branch,and operational constraints of power electronics transformers.In this paper,convex relaxation technique is used to transform the OPF problem into a semi-definite programming(SDP)problem,and the sufficient conditions for zero relaxation gap are derived to obtain global optimal solution.The simulation on extended IEEE 33 test system with PETs proves that the sufficient condition of zero relaxation gap is applicable to actual hybrid AC/DC power grid,and the global optimal solution can be obtained.

关 键 词：交直流混合电网 电力电子变压器 最优潮流 半定规划 

分 类 号：TM721[电气工程—电力系统及自动化]