直流控制策略及对电网稳定性的影响

Effects of DC Control Strategies on DC Power Transmission System Stability

分析了直流控制策略及其在电网中的应用,比较了定电流控制和定功率控制的原理及实现.以南方电网高肇直流输电系统为例,设计了不同传递函数的电流控制器.用仿真程序研究了相同条件下定电流控制和定功率控制对电网稳定性的影响、电流控制器的动态响应以及直流调制的作用.研究结果表明,如参数选择得当,定电流和定功率控制方式下的系统稳定水平相当;采用PI控制器构成的电流控制器超调量小,响应迅速,调节性能好;直流调制可以增加交流系统的阻尼,提高电网稳定性.

DC （direct current） control strategy and its application in power transmission systems were analyzed, and constant current control （CCC） and constant power control （CPC） were compared in terms of their principles and implementation. Gao-Zhao （Gaopo in Guizhou to Zhaoqing in Guangdong） HVDC （high voltage DC） transmission system in China Southern Power Grid was taken as an example. Current controllers with different transfer functions were designed. Simulations were performed on the system stability of power networks, dynamic responses of current controllers and effects of DC modulation by CCC or CPC under the same parameters. The results show that, with proper parameters, CCC and CPC obtain similar stabilities; a PI controller delivers small current overshooting, fast responses and a good adjustability; and DC modulation increases system damping so as to raise power network stability.