半波长交流输电柔性调谐的控制策略与仿真分析

Control strategy and simulation analysis of flexible tuning scheme of half-wavelength AC transmission

半波长交流输电要求线路送受端的电气距离接近半个工频波长。当线路的电气长度不足半个波长时,需要进行人工调谐以确保线路呈现半波长特性。针对现有无源型调谐网络的不足,提出了π型半波长输电柔性调谐装置,包括两组并联调谐器和一组串联调谐器。结合并联调谐器和串联调谐器的主电路结构及工作原理,设计了适用于半波长柔性调谐的控制策略,并通过仿真验证了π型柔性调谐装置的可行性。通过适当的控制策略,柔性调谐装置可实现功率因数补偿这一附加功能,仿真结果表明,在实施功率因数补偿后,避免了无功功率经过半波长线路,减小了半波长线路沿线电压、电流的波动。

Half-wavelength AC transmission(HWACT)requires that the electrical length between the sending and receiving ends is about one half of a power frequency wavelength.If the electrical length is shorter than one half of the fundamental frequency wavelength,the appropriate technology should be employed to compensate the electrical length in order to maintain the HWACT characteristics.In order to overcome various drawbacks of the existing passive tuning,this paper proposes aπtype half-wavelength transmission flexible tuning device,including two parallel tuners and one series tuner.Then,based on their main circuit topologies and their working principle,their control strategy is designed for the half wavelength flexible tuning,and the simulation results confirm that the proposedπtype flexible tuning device is feasible.With the appropriate control strategy,the flexible tuning device can realize the additional function of power factor compensation,and the simulation results show that with the implementation of the power factor compensation function,the reactive power will not pass through the half wavelength AC transmission line,as a consequence the fluctuation amplitude of voltage and current along the half wavelength line will be reduced.