特高压直流接入背景下的UPFC系统级控制策略

为缓解特高压直流馈入受端电网后造成的多个交流输电通道紧张的问题,提高换流站交流母线暂态电压支撑强度和稳态调压能力,首先基于电网络理论推导了统一潮流控制器(UPFC)对输电线路电流、交流母线电压的控制灵敏度,分析了利用UPFC系统级控制功能(线路有功/无功潮流控制以及并联换流器无功功率控制)实现输电线路过载控制和交流母线电压调节的可行性。在此基础上,提出了一套特高压直流接入背景下的UPFC系统级控制策略,以监控系统运行参数并自动生成满足系统安全稳定约束的UPFC系统级控制指令值。最后,以锦苏直流落点附近的苏南500 kV UPFC示范工程作为仿真算例,验证了所提出的控制灵敏度分析的有效性和UPFC系统级控制策略的可行性。

System-level Control Strategy for UPFC Power Grids Integrated with UHVDC

To alleviate the problem of line overload raised by the integration of ultra-high voltage direct current(UHVDC)transmission systems, and to enhance the voltage support strength of the AC bus of the UHVDC station, the sensitivities of line loads and AC bus voltage magnitudes to the control of unified power flow controller(UPFC)are deduced based on electrical network theories. Then, the feasibility of the active/reactive power flow control ability of the series converter and the reactive power control ability of the shunt converter to achieve line overload control and voltage regulation is analyzed. On this basis, a UPFC control strategy for power grids integrated with UHVDC is developed. Using this control strategy, the system-level settings of the UPFC are generated automatically based on current/voltage measurements. Finally, a case study is done in the Suzhou southern power grid of China, where the 500 kV UPFC project and Jinping-Sunan UHVDC transmission system are located. The effectiveness of control sensitivity analysis and the feasibility of proposed control strategy are verified in the case study.