基于UPFC&DC-SDC的交直流电网低频振荡抑制研究

针对交直流混联电网的低频振荡问题,提出一种将统一潮流控制器(Unified Power Flow Controller, UPFC)及直流附加阻尼控制器(DC Supplementary Damping Controller, DC-SDC)相结合的UPFCDC-SDC综合阻尼控制系统。为使UPFCDC-SDC综合控制系统发挥最佳控制效果,由UPFC及DC-SDC的状态变量,推导了含UPFCDC-SDC综合控制系统的基于VSC-HVDC的交直流混联系统特征根增广矩阵。基于该矩阵计算了多运行方式下系统小干扰概率特征值。以该矩阵特征值实部加权后的和最小为目标函数,考虑该矩阵阻尼比、线路传输极限及安全等约束,构建了确定UPFCDC-SDC综合控制系统参数的优化方程,并通过粒子群优化算法求解。以CEPRI36v7系统为例,验证了所提方法能在不制约直流输电能力的同时抑制低频振荡。

Study on damping low frequency oscillation of an AC/DC power grid based on UPFC & DC-SDC

In order to damp the low-frequency oscillation of an AC/DC hybrid power grid, a UPFC & DC-SDC integrated control system is proposed. This combines the Unified Power Flow Controller (UPFC) with the DC Supplementary Damping Controller (DC-SDC). In order to make the UPFC & DC-SDC control system have the best control effect, the eigenvalue augmentation matrix of AC/DC hybrid system based on VSC-HVDC is obtained from the state variables of UPFC & DC-SDC. Based on the matrix, the eigenvalues of small signal probability are calculated of multi-operating modes. The objective function is to minimize the weighted sum of the real part of the probabilistic eigenvalue. Considering the eigenvalue augmented matrix damping ratio, transmission limit and safety voltage constraints, an optimization equation for determining the parameters of the UPFC & DC-SDC integrated control system is constructed and solved by a particle swarm optimization algorithm. Taking the CEPRI36v7 system as an example, it is verified that the control strategy can damp low-frequency oscillation without restricting DC transmission capacity. This work is supported by National Key Research and Development Program of China (No. 2018YFB0904503) and Scientific and Technological Project of Guangdong Power Grid Co., Ltd. (No. GDKJXM20180125).