双向VSC-HVDC传输系统的归一化控制与运行

Normalized Control and Operation of VSC-HVDC Bidirectional Transmission System

针对部分地区由于地理位置以及季节性差异引起的能源不平衡现象,提出了基于电压源换流器的高压直流输电(voltage source converter-high voltage direct current,VSC-HVDC)系统双向传输的归一化控制策略,实现了分区联络电网能源优势互补。首先,将电压源换流器两侧的下垂特性归一化,获得交直流电网的传输功率参考值;然后,比较直流输电线路两端传输功率参考值的大小与方向,确定直流输电线路的传输功率;最后,通过控制直流线路两端的直流电压,实现功率双向传输,平衡两侧交流电网的功率。设计了3种不同的工作情景,采用实时数字仿真器(real time digital simulator,RTDS)进行了仿真研究,仿真结果验证了控制的有效性,实现了低碳电力调度。

In viewof the imbalanced phenomenon of energy caused by the geographical location and seasonal variation,this paper proposes a normalized control strategy with bidirectional transmission based on voltage source converter-high voltage direct current（ VSC-HVDC） system,which can contact grid by partition to realize the complementary advantages.Firstly,the control system determines the reference value of transmission power between AC and DC system through normalizing the droop characteristics on both sides of voltage source converter. Then,we obtain the transmission power of DC transmission line through comparing the size and direction of the reference value of the transmission power between the two ends of DC transmission line. Finally,it achieves bidirectional transmission and power balance between two grids by controlling the DC voltage at both ends of DC line. We design three different work situations and carry out simulation study in real time digital simulator（ RTDS）. The simulation results verify the effectiveness of the proposed control strategy,which realizes the lowcarbon power dispatching.