电网短路故障下新能源并网变换器的暂态同步机制及其自适应稳定控制策略  

Transient Synchronization Mechanism and Adaptive Stability Control Strategy for Renewable Energy Grid-connected Converter Under Grid Faults

作　　者：裴金鑫 姚骏[1] 黄森 陈诗玥 陈朝阳 迟永宁 田新首 PEI Jinxin;YAO Jun;HUANG Sen;CHEN Shiyue;CHEN Zhaoyang;CHI Yongning;TIAN Xinshou(State Key Laboratory of Power Transmission Equipment&System Security and New Technology(Chongqing University),Shapingba District,Chongqing 400044,China;State Key Laboratory of Operation and Control of Renewable Energy&Storage Systems(China Electric Power Research Institute),Haidian District,Beijing 100192,China)

机构地区：[1]输配电装备及系统安全与新技术国家重点实验室(重庆大学),重庆市沙坪坝区400044 [2]新能源与储能运行控制国家重点实验室(中国电力科学研究院有限公司),北京市海淀区100192

出　　处：《中国电机工程学报》2022年第16期5922-5934,共13页Proceedings of the CSEE

基　　金：国家自然科学基金委员会–国家电网公司智能电网联合基金项目(U1966208);国家自然科学基金项目(51977019)。

摘　　要：新能源并网变换器在电网短路故障期间与电网之间的交互作用显著增强,增加了暂态失稳风险。该文首先建立可再生能源并网换流器(renewable energy grid-connected converter,REGC)在低电压穿越(low-voltageride-through,LVRT)期间的简化等效转子摇摆方程,刻画并分析其同步特征属性。然后,借鉴传统同步发电机的同步稳定理论,推导等效整步转矩系数、等效等面积准则以及阻尼比3个同步特征指数,物理性地揭示不平衡虚拟转矩驱动REGC等效功角运动,甚至引发暂态失步的内在机理,并同时量化衡量REGC的暂态同步稳定性及其在低电压穿越期间的准静态小干扰同步稳定性。最后,提出一种基于自动虚拟变阻器的改进锁相环(phase-lockedloop,PLL)架构,使REGC能够自适应地抵消/补偿线路电阻的压降效应,不仅具备自主平衡能力,而且同时显著增强REGC的暂态同步稳定性及其准静态小干扰同步稳定性。仿真和实验结果验证了理论分析的正确性和所提控制策略的有效性。The interaction between renewable energy grid-connected converter(REGC)and power grid is significantly strengthened under the grid fault,which increases the risk of transient synchronization instability.In this paper,the simplified equivalent rotor swing equation of REGC during low-voltage ride-through(LVRT)period was established,and its synchronization characteristic properties were defined and analyzed.Secondly,referring to the synchronous stability theory of traditional synchronous generators,this paper proposed three synchronization characteristic indexes to physically reveal the synchronization mechanism of the REGC,involving the equivalent synchronizing torque coefficient,equivalent equal area criterion and damping ratio.These indexes can also quantitatively measure REGC’s transient synchronization stability as well as the quasi-static small disturbance synchronization stability during LVRT.Finally,this paper proposed an automatic virtual rheostat-based improved phase-locked loop(PLL)scheme to help the REGC have the self-balanced capability,and thus significantly enhanced the transient synchronization stability of REGC.The correctness of the analysis and effectiveness of the proposed control scheme were verified by simulations and experiments.

关 键 词：电网短路故障 低电压穿越 新能源并网变换器 暂态同步稳定性 自适应稳定控制 

分 类 号：TM46[电气工程—电器]