基于电力电子变压器的电网建模和稳定性分析  

Modeling and stability analysis of SST-based grid

作　　者：刘星琪 窦真兰 迟福海 邓任任 汤建 徐若凯 邹志翔[1] 王政[1] 程明[1] LIU Xingqi;DOU Zhenlan;CHI Fuhai;DENG Renren;TANG Jian;XU Ruokai;ZOU Zhixiang;WANG Zheng;CHENG Ming(School of Electrical Engineering,Southeast University,Nanjing 210096,China;State Grid Shanghai Electric Power Company,Shanghai 200122,China;NARI Group(State Grid Electric)Power Research,Nanjing 211106,China;Nari Technology Co.,Ltd.,Nanjing 211106,China)

机构地区：[1]东南大学电气工程学院,南京210096 [2]国网上海市电力公司,上海200122 [3]南瑞集团(国网电力科学研究院)有限公司,南京211106 [4]国电南瑞科技股份有限公司,南京211106

出　　处：《北京交通大学学报》2021年第6期32-42,共11页JOURNAL OF BEIJING JIAOTONG UNIVERSITY

基　　金：国家自然科学基金(52007033);国家电网公司科技项目“基于混合储能的电动船舶岸电与互动技术研究”(5400-202140398A-0-0-00)。

摘　　要：随着电力系统中新能源比例加大,电力电子变压器(Solid-State Transformer,SST)以其显著优势正逐渐替代传统变压器,但SST的接入也带来一系列建模和稳定性问题.针对系统建模和稳定性问题,首先利用小信号建模方法建立了SST低压侧变换器、新型PQ节点和新型PV节点的阻抗模型.其次,利用传递函数极点研究了SST在连接不同节点时系统的稳定性,尤其是线路阻抗和电压环参数对系统稳定性的影响.然后,采用参数敏感性分析研究了电压环比例增益k_(pv)和线路长度对系统的影响程度.最后,利用仿真验证理论模型的正确性.研究结果表明:SST与PQ节点相连时,线路长度和k_(pv)的增加会导致系统失稳并且该系统更适用于阻性线路;SST与PV节点相连时,线路长度的减少和k_(pv)的增加会导致系统失稳并且该系统更适用于感性线路;k_(pv)和线路长度之间存在交互影响并且k_(pv)对系统稳定性的影响程度要远大于线路长度.As the proportion of renewable energy in the power system increases,Solid-State Transformers(SSTs)are gradually replacing traditional transformers with their significant advantages.However,the introduction of SST brings a series of modeling and stability problems.Aiming at addressing the problems of system modeling and stability,this paper firstly establishes the impedance model of the low-voltage side SST,new PQ node,and new PV node by small signal modeling method.Then,poles in transfer functions are used to analyze the stability of the SST when different buses are connected,especially the influence of line impedance and voltage loop parameters on system stability.Then,parameter sensitivity analysis is conducted to study the influence of SST voltage loop proportional parameter k_(pv) and line length on the system.Finally,simulations are used to verify the feasibility of the theoretical model.Research results shows that when the SST is connected to the PQ node,the increase of line length and k_(pv) lead to system instability and this system is more suitable for resistive lines;when the SST is connected to the PV node,the decrease of line length and the increase of k_(pv) lead to system instability and this system is more suitable for inductive lines.Moreover,there is an interactive influence between k_(pv) and line length,and the influence of k_(pv) on system is much greater than that of the line length.

关 键 词：电力电子变压器 稳定性 PQ节点 PV节点 平衡节点 

分 类 号：TM712[电气工程—电力系统及自动化]