摘要
传统基于锁相环(phase lock loop,PLL)电网跟踪型控制在电网短路比(short circuit ratio,SCR)较低或PLL带宽较高情况时,给电力系统引入负阻尼导致系统不稳定。为此,提出了一种不依赖PLL的用于区域间电网互联的新型电压源换流器(voltage source converter,VSC)虚拟同步控制。首先,构造VSC直流电压与受端系统频率间的下垂特性,当受端电网受扰后,受端换流器可为系统提供惯量支撑。其次,测量送端电压波动与直流电流波动可计算受端交流系统的频率扰动,通过模拟同步机的一次调频特性,在受端电网受扰时,送端电网可不依赖通信为受端电网提供频率支撑。与传统控制相比,在系统受扰时,利用电容储能及送端电网的调频能力为其提供频率支撑。基于PSCAD/EMTDC仿真算例验证了受端系统弱SCR场景、负荷变化场景下所提控制策略的有效性。
PLL-based grid-following control might induce negative damping and result in the instability of an overall meshed AC/DC system in the case of a low grid short circuit ratio or the high bandwidth control of PLL.To overcome the drawbacks of conventional PLL-based control,this paper proposes novel virtual synchronous control for VSC-based HVDC systems without the requirement of PLL for the interarea connection of power grids.In the proposed control method,the droop property between DC-link voltage and the frequency of a receiving-end system is artificially constructed.As a result,emulated inertia support can be provided from the DC-link capacitor for the system under severe system frequency deviations.Moreover,a sending-end AC system can sense the frequency disturbance in the receiving-end system without remote communication by utilizing the local DC-link voltage and current variations in the VSC-based rectifier.In addition,the sending-end system can provide the primary frequency control for the disturbed system on the other side by fully emulating the primary frequency regulation of a conventional synchronous generator.Compared with the conventional PLL-based control of VSC,the proposed control strategy is different in that it fully utilizes the grid-forming and grid-support potential of VSC for the disturbed AC system without relying on PLL and remote communication.Furthermore,the stability of the receiving-end system is considerably improved by the proposed scheme.The effectiveness of the proposed control method is validated through the simulation of abrupt load variations using PSCAD/EMTDC.
作者
刘宏伟
袁枭添
洪昊
王丽群
吴非斐
李宇骏
LIU Hongwei;YUAN Xiaotian;HONG Hao;WANG Liqun;WU Feifei;LI Yujun(State Grid Hangzhou Power Supply Company,Hangzhou 310000,Zhejiang Province,China;School of Electrical Engineering,Xi’an Jiaotong University,Xi’an 710049,Shaanxi Province,China;Hangzhou Power Equipment Manufacturing Co.,Ltd.,Hangzhou 310004,Zhejiang Province,China)
出处
《全球能源互联网》
2020年第2期142-150,共9页
Journal of Global Energy Interconnection
基金
国家自然科学基金(51807150)
杭州电力设备制造有限公司科技项目(交直流柔性互联配电网规划及协同控制技术研究与示范,HD020112001039).
关键词
电压源换流器
区域间互联
虚拟同步控制
频率支撑
voltage source converter
interarea connection
virtual synchronous control
frequency support
作者简介
刘宏伟(1979),男,硕士研究生,主要从事电力系统运行和控制研究工作,E-mail:12298656@qq.com;通信作者:袁枭添(1994),男,博士研究生,主要从事新能源电力系统稳定性分析与控制方面的研究工作。E-mail:yxt2013@stu.xjtu.edu.cn;洪昊(1987),男,本科,主要从事电力系统运行和控制研究工作,E-mail:409061604@qq.com;王丽群(1979),女,本科,电气工程师,主要从事电气设备研发、工程设计工作,E-mail:wangliqun1219@163.com;吴非斐(1980),女,本科,电气工程师,主要从事电气设备研发、工程设计工作,E-mail:twotwo512@163.com;通信作者:李宇骏(1990),男,副教授,主要从事风机建模与控制、直流输电系统仿真建模方面的研究工作。E-mail:yujunli@xjtu.edu.cn。
