计及可再生能源不确定性的孤岛微电网概率潮流计算

随着具有不确定性的可再生能源接入孤岛微电网的比例不断提高,传统确定性条件下孤岛微电网的潮流计算受到挑战。基于有功功率—频率/无功功率—电压(P-f/Q-U)控制和有功功率—电压/无功功率—频率(P-U/Q-f)控制两种下垂控制策略,在计及可再生能源的不确定性时,建立了综合控制下孤岛交流微电网的概率潮流计算模型,并提出了一种改进的三步LevenbergMarquardt(MTLM)算法对潮流方程进行求解。采用基于Sobol序列的拟蒙特卡洛模拟获得具有随机性的可再生能源出力和负荷的样本,进而对38节点孤岛交流微电网进行概率潮流计算,通过对比验证了MTLM算法的快速收敛性和鲁棒性,研究了不同下垂控制策略下系统频率和电压的概率分布情况,分析了具有随机性的高比例可再生能源接入对孤岛微电网的影响。

Probabilistic Power Flow Calculation of Islanded Microgrid Considering Uncertainty of Renewable Energy

With the increase of the proportion for renewable energy sources access to islanded microgrid, the power flow calculation of the islanded microgrid under the traditional deterministic conditions is challenged. Based on the two droop control strategies of active power-frequency/ reactive power-voltage(P-f/Q-U)and active power-voltage/reactive power-frequency(P-U/Q-f), a probabilistic power flow model considering the uncertainty of renewable energy for islanded AC microgrid under comprehensive control is established. Meanwhile, a modified three-step Levenberg-Marquardt(MTLM)algorithm is proposed to solve the power flow equation. A quasi-Monte Carlo simulation based on the Sobol sequence is used to obtain the samples of stochastic renewable energy and loads, then the probabilistic load flow calculation of the 38-node islanded microgrid is carried out. The fast convergence and robustness of the MTLM algorithm are verified by comprising with other methods. Moreover, the probability distribution functions of frequency and voltage under different droop control strategies are studied, and the influence of stochastic renewable energy access to islanded microgrid is analyzed.