提高弱交流系统下混合多端直流输电系统小干扰稳定性的控制参数优化调节方法  

Optimal Adjustment Method of Control Parameters for Improving Small-Signal Stability of Hybrid Multi-Terminal HVDC System under Weak AC Condition

作　　者：郑安然 郭春义 殷子寒 赵成勇 Zheng Anran;Guo Chunyi;Yin Zihan;Zhao Chengyong(State Key Laboratory for Alternate Electrical Power System with Renewable Energy Sources North China Electric Power University,Beijing 102206 China)

机构地区：[1]新能源电力系统国家重点实验室(华北电力大学),北京102206

出　　处：《电工技术学报》2020年第6期1336-1345,共10页Transactions of China Electrotechnical Society

基　　金：国家自然科学基金面上资助项目(51877077)。

摘　　要：整流站采用电网换相型换流器(LCC)、逆变站采用模块化多电平换流器(MMC)的混合多端直流输电系统(H-MTDC)连接弱交流系统时,若控制参数设置不合理,系统可能出现小干扰失稳现象,限制了混合多端直流输电系统在弱交流场合下的应用。该文提出一种提高弱交流系统下混合多端直流输电系统小干扰稳定性的控制参数优化调节方法。首先,基于混合多端直流输电系统的小干扰模型,采用特征根分析法研究不同换流站所联接的交流系统强度对混合多端直流输电系统小干扰稳定性的影响,结果表明不合理的控制参数会降低系统的稳定裕度,继而诱发小干扰失稳问题。然后以混合三端直流输电系统为例,给出一种基于灵敏度分析的控制参数优化调节方法,优化了混合三端直流输电系统的控制参数。PSCAD/EMTDC的详细电磁暂态仿真结果表明,采用优化后的控制系统参数提高了连接弱交流系统时混合三端直流输电系统的小干扰稳定性。The hybrid multi-terminal high voltage direct current(H-MTDC)system uses the Line Commutated Converter(LCC)for rectifiers and the Modular Multilevel Converter(MMC)for inverters.When the H-MTDC system is connected to a weak AC system,if the control parameters are set unreasonably,small-signal instability may occur in the system,which limits the application of the H-MTDC system under weak AC condition.In this paper,a control parameter optimization method was proposed to improve the small-signal stability of H-MTDC system under weak AC condition.First,based on the small-signal model of H-MTDC system,the eigenvalue analysis method was used to study the impact of the strength of AC grid connected at different converter stations on the small-signal stability of H-MTDC.The results show that unreasonable selection of control parameters will reduce the stability margin of the system,and then induce the corresponding small-signal instability.Taking the hybrid three-terminal high voltage direct current(HVDC)system as an example,this paper presented a control parameter optimization method based on sensitivity analysis,and optimized the control parameters of the hybrid three-terminal HVDC system.The detailed electromagnetic transient simulation results in PSCAD/EMTDC show that the small-signal stability of hybrid three-terminal HVDC system under weak AC grid condition can be improved by the optimized control system parameters.

关 键 词：混合多端直流输电系统 弱交流系统 控制参数优化 灵敏度分析 

分 类 号：TM721.1[电气工程—电力系统及自动化]