摘要
电网电压不对称是VSC-HVDC系统实际运行时不可避免的问题,由于常规控制下的VSC在电网电压不平衡时会将直流侧二次频波动通过传输电路传播到相邻换流站,会引起传输功率发生波动,进而影响直流输电系统的稳定运行。针对这一问题,对VSC进行功率分析并研究其不平衡控制方案。同时采用了VSC侧与交流侧复合功率控制方法,得出了不平衡条件下功率外环指令电流模型,设计了αβ静止坐标下Terminal滑模内环控制器。最后,在电磁暂态仿真软件PSCAD/EMTDC环境下搭建VSC-HVDC模型,仿真结果验证了该方案的有效性。
Unsymmetrical grid normal control win transmit the circuit when the grid voltage is dc transmission system. Aiming control plan. At the mean unbalanced condition by u voltage is inevitable in the operation of VSC - HVDC system. Since VSC under secondary frequency fluctuation at dc side to the converter nearby via transmission unbalance, the transmission power fluctuates which influences the stable operation of at the problem, this paper analyzes the power of VSC and studies its unbalanced time, the paper works out the command current model of outer - loop power under tilizing hybrid power control at VSC side and ac side and designs the Terminal sliding inner - loop controller with αβ static coordinate. Finally, the VSC - HVDC model is established under electromag- netic transient simulation software PSCAD/EMTDC. The simulation result verifies the effectiveness of the strategy.
出处
《黑龙江电力》
CAS
2013年第4期283-286,290,共5页
Heilongjiang Electric Power
