弱交流系统下光伏经柔直送出系统的稳定运行极限及提升方法  

Stable operation limit and improving method of photovoltaic via flexible DC sending system under weak AC system

作　　者：赵薇 郭春义[1] 张舒文 彭茂兰 冯雷 ZHAO Wei;GUO Chunyi;ZHANG Shuwen;PENG Maolan;FENG Lei(State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources,North China Electric Power University,Beijing 102206,China;Maintenance and Test Center,EHV Power Transmission Company of China Southern Power Grid Co.,Ltd.,Guangzhou 510663,China)

机构地区：[1]华北电力大学新能源电力系统全国重点实验室,北京102206 [2]中国南方电网有限责任公司超高压输电公司检修试验中心,广东广州510663

出　　处：《电力自动化设备》2024年第10期39-45,共7页Electric Power Automation Equipment

基　　金：中国南方电网有限责任公司超高压输电公司科技项目(0120002022030301SJ00046)。

摘　　要：弱交流系统下大规模新能源接入的柔直系统的稳定运行范围影响着系统的新能源消纳能力。建立了弱交流系统下光伏经柔直送出系统的稳态数学模型与状态空间模型,综合考虑了系统稳态运行约束和小信号稳定性约束,提出了系统稳定运行区域的计算方法,定量评估了不同送端交流系统短路容量和光伏出力下系统稳态约束范围与小信号稳定性约束边界的变化特征。研究发现随着送端交流系统短路容量的降低与光伏出力的增大,小信号稳定性约束在稳态约束范围的基础上进一步限制了系统的稳定运行区域。通过特征值分析和参与因子分析,研究了影响弱交流系统下小信号稳定性的关键影响因素,提出了一种附加频率阻尼控制策略,由此在一定程度上扩大了系统稳定运行范围。在PSCAD/EMTDC中搭建了弱交流系统下光伏经柔直送出系统的仿真模型,验证了理论分析和计算结果的正确性。The stable operation range of flexible DC system connected with large-scale new energy under weak AC system affects the new energy absorption capacity of the system.The steady-state mathematical model and state space model of the photovoltaic sending system via flexible DC under weak AC system are established.A method comprehensively considering the stable operation and the small signal stability constraints is proposed,which can calculate the stable operation region of the system.The variation charac⁃teristics of steady-state constraint range and small signal stability constraint boundary of MMC-HVDC un⁃der different short circuit capacity of sending AC system and photovoltaic output are quantitatively evaluated.It is found that with the decrease of the short circuit capacity of sending AC system and the increase of the photovoltaic output,the small signal stability constraint further limits the stable operation region of the system on the basis of steady state constraints.Through the eigenvalue analysis and participation factor analysis,the key factors affecting the small signal stability in weak AC system are studied.Furthermore,a supplementary frequency damping control strategy is proposed,which expands the stable operation range of the system to a certain extent.The simulation model of photovoltaic sending system via flexible DC under weak AC system is built in PSCAD/EMTDC to verify the correctness of the theoretical analysis and cal⁃culative results.

关 键 词：弱交流系统 光伏 柔直系统 稳定运行极限 附加频率阻尼控制 

分 类 号：TM712[电气工程—电力系统及自动化] TM615