基于PSCAD/EMTDC的统一潮流控制器动态仿真模型

设计了组成统一潮流控制器(UPFC)的动态仿真模型的各个模块,包括正弦脉宽调制(SPWM)信号产生模块、电压源变换器(VSC)控制模块和UPFC控制器的比例积分(PI)控制电路.首先采用三相桥式全控电路组成VSC,VSC的开关器件采用绝缘栅双极性晶体管(IGBT),门极信号按SPWM的方式产生.然后通过分析线路传输功率方程设计了一个简单的PI控制器,并构成完整的UPFC仿真模型.还基于该动态模型对UPFC在功率调节、电压控制和抑制振荡等方面的功能进行了仿真分析.仿真结果表明该UPFC仿真模型在线路功率发生较大变动时能使线路快速恢复;在系统发生三相短路时能有效减少系统的功率损失和减小母线电压的暂降幅度;在系统发生功率波动时还能大幅度减小振幅.

DYNAMIC SIMULATION MODEL OF UNIFIED POWER FLOW CONTROLLER BASED ON PSCAD/EMTDC

The authors design the modules constituting a dynamic simulation model for unified power flow controller (UPFC), including the module generating the signal for sinusoidal pulse width modulation (SPWM), the control module of voltage source converter (VSC), the proportional- integral (PI) control circuit of UPFC controller. Firstly, three-phase bridge full-controlled circuit is adopted to constitute the converters, in which IGBT are employed as the switch components, and the gate-firing signals of IGBT are obtained by use of SPWM method. Secondly, according to the analysis result of active and reactive power characteristics of transmission line a simple PI controller is designed and whole UPFC dynamic model is accomplished. Finally, the functions of UPFC such as enhancing transient stability, maintaining bus voltage and damping system oscillation are simulated by the designed UPFC dynamic model, the simulation results show that this UPFC model can rapidly recover transmission ability while evident variation of transmitted power occurs, effectively reduce the power losses of the system and the amplitude of busbar voltage sag when three phase grounding fault takes place, and considerably reduce the amplitude of oscillation when power oscillation in the transmission line appears.