摘要
基于电压源换流器的多端直流输电(multi-terminalHVDC system based on voltage source converter,VSC-MTDC)系统具有有功功率、无功功率四象限独立控制、多电源供电、多落点受电,可连接无源网络等特点,近年来受到广泛关注。VSC-MTDC控制器的参数决定了其控制系统的控制能力,从而决定了系统的运行特性,而试凑法得到直流输电系统的控制参数不能保证系统良好的运行特性,提出了VSC-MTDC系统运行特性的评价指标,并以其作为单纯形法的目标函数对控制系统参数优化,从而保证VSC-MTDC系统具有良好的运行特性。同时,VSC-MTDC系统的调整策略决定了调整过程中系统的运行特性,较大的目标值调整会导致系统电气量的剧烈波动和较长的调整时间,不利于系统稳定和设备安全,据此提出了控制器参考值在一定的时间内按照某一曲线逐步逼近目标值的控制方法,即柔性调整方式。基于PSCAD/EMTDC的仿真结果表明,采用所提出的优化方法后,系统的响应特性有较明显改善;柔性调整策略更有利于系统的稳定和设备的安全。
Since the voltage source converter based multi terminal HVDC （VSC-HVDC） transmission system possesses such advantages as independent control of active and reactive power in four quadrants, enable to be connected with multi power sources and multi receiving ends, enable to be connected with passive network and so on, it attracts extensive attentions. The control ability of VSC-MTDC controller depends on the parameters of its controller, thus the operating characteristics of VSC-HVDC transmission system is correspondingly determined. The operating characteristics of VSC-HVDC transmission system cannot be ensured by the control parameters achieved by cut-and-try process method, so the evaluation index for operating characteristics of VSC-HVDC transmission system is proposed, and is taken as the objective of the simplex method to oPtimize the parameters of the control system to ensure VSC-HVDC transmission system enable to possess satisfied operating characteristics. Meanwhile, the operating characteristics of VSC-HVDC transmission system during the regulation is determined by its regulation strategy, so a larger target value may lead to severe fluctuation Of electric quantities and a longer regulation time and those are harmful to System stability and equipment security, for this reason, a novel control method, by which the reference value of the controller is gradually approximated to the target value according to a certain curve within a specified time period, namely the flexible regulation, is put forward. PSCAD/EMTDC based simulation results show that using the proposed method the response characteristic of the control system is obviously improved, therefore the flexible regulation is more beneficial to system stability and equipment security.
出处
《电网技术》
EI
CSCD
北大核心
2015年第2期380-386,共7页
Power System Technology
基金
国家高技术研究发展计划(863计划)(2012AA050208)
高等学校学科创新引智计划项目(B08013)~~
