用于 VSC-HVDC 互联系统的附加频率控制策略

摘要

为使柔性直流输电(VSC-HVDC)系统两侧交流系统在发生事故时具有相互支援的能力，文中提出一种附加频率控制策略。该策略在定有功功率控制器中引入了频率-有功功率和直流电压-有功功率斜率特性，在定直流电压控制器中引入频率-直流电压斜率特性，不需要站间通信就可以实现两端交流系统通过 VSC-HVDC 参与彼此的频率调整，减轻事故端系统的调频负担，提高故障期间直流系统的安全稳定性。最后，通过仿真软件 PSCAD/EMTDC 进行仿真验证，结果表明所提策略充分利用了 VSC-HVDC 互联系统的频率调整能力，提高了 VSC-HVDC 互联系统的频率稳定性。%In order to enable the AC systems at the two sides of voltage source converter based high voltage direct current (VSC-HVDC) system to provide frequency support to each other under a fault,an additional frequency control strategy is proposed.The droop characteristics of frequency-active power and DC voltage-active power are introduced in the active power controller,meanwhile the droop characteristics of frequency-DC voltage are introduced in the DC voltage controller.Both the AC systems can participate in each other”s frequency adjustment through VSC-HVDC without interstation communications. The frequency adjustment burden of the AC system under fault will be relieved,and the frequency stability of the DC system will be improved as well.Finally,simulations with PSCAD/EMTDC verify that the proposed control strategy is able to enhance the frequency stability with full use of the frequency adjustment ability. This work is supported by National Basic Research Program of China (973 Program)(No.2013CB2280204) and State Grid Corporation of China.