光伏与LCC-HVDC系统的次同步振荡耦合路径及阻尼特性分析  

Analysis on Coupling Path and Damping Characteristics of Sub-synchronous Oscillation Between Photovoltaic and LCC-HVDC System

作　　者：高本锋[1] 陈淑平 刘毅 GAO Benfeng;CHEN Shuping;LIU Yi(Hebei Key Laboratory of Distributed Energy Storage and Micro-grid(North China Electric Power University),Baoding 071003,China;Zaozhuang Power Supply Company of State Grid Shandong Electric Power Company,Zaozhuang 277100,China;Suzhou Power Supply Company of State Grid Jiangsu Electric Power Co.,Ltd.,Suzhou 215000,China)

机构地区：[1]河北省分布式储能与微网重点实验室(华北电力大学),河北省保定市071003 [2]国网山东省电力公司枣庄供电公司,山东省枣庄市277100 [3]国网江苏省电力有限公司苏州供电分公司,江苏省苏州市215000

出　　处：《电力系统自动化》2022年第24期66-75,共10页Automation of Electric Power Systems

基　　金：国家重点研发计划资助项目(响应驱动的大电网稳定性智能增强分析与控制技术,2021YFB2400800)。

摘　　要：随着电网换相型高压直流(LCC-HVDC)系统送端近区光伏容量的增加,光伏经LCC-HVDC外送系统的振荡稳定性问题日益凸显。然而,光伏与LCC-HVDC系统的次同步交互作用尚不明确,相关研究较少。为此,首先建立光伏经LCC-HVDC外送系统的闭环传递函数框图,探明次同步分量在光伏与LCC-HVDC系统间传递时的耦合路径;然后,提出一种阻尼分离方法,评估交互作用对系统次同步振荡(SSO)阻尼的影响;最后,结合时域仿真进行影响因素分析。研究结果表明:光伏自身的闭合回路及光伏与LCC-HVDC系统、交流系统的耦合路径均经过与直流电容振荡模态相关的传递函数,导致各类交互作用阻尼特性共同决定系统SSO特性;对于所提算例,光伏与交流系统、光伏与LCC-HVDC系统的交互作用为SSO提供负阻尼;LCC-HVDC系统定电流控制器和光伏逆变器外环的比例系数减小、积分系数增大,或光照强度增大时,系统SSO风险增大。With the increase of photovoltaic capacity near the sending-end of line-commutated-converter based high voltage direct current(LCC-HVDC) system, the oscillation stability of photovoltaic transmission system via LCC-HVDC is prominent.However, sub-synchronous interaction between photovoltaic and LCC-HVDC system is still unclear, and there are few related studies. Thus, the closed-loop transfer function block diagram of photovoltaic stations via LCC-HVDC system is established.Based on this, the sub-synchronous component coupling path between photovoltaic and LCC-HVDC system is revealed. Then, a damping separation method is proposed to evaluate the effects of sub-synchronous interactions on the system damping. Finally, the influencing factors are analyzed by time domain simulation. The results show that the closed loop of photovoltaic, the coupling path between photovoltaic, LCC-HVDC system, and AC system all pass through the transfer function related to the subsynchronous oscillation mode dominated by DC capacitance, resulting in the damping characteristics of various interactions jointly determining the sub-synchronous oscillation(SSO) characteristics of the system. For the case in this paper, the interaction between photovoltaic and AC system as well as photovoltaic and LCC-HVDC system provides negative damping for SSO. When the proportional coefficient of the outer loop of the photovoltaic grid-connected inverter and the LCC-HVDC system rectifier decreases, the integral coefficient of the outer loop of the photovoltaic grid-connected inverter and the LCC-HVDC system rectifier increases, or illumination intensity increases, the risk of SSO increases.

关 键 词：光伏 电网换相型高压直流输电 阻尼转矩 阻尼分离 次同步振荡 

分 类 号：TM712[电气工程—电力系统及自动化]