考虑随机变量相关性的交流概率潮流风险评估

Risk Assessment About Nonlinear AC Probabilistic Load Flow Considering Correlation Between Stochastic Variables

随机变量除了由非线性潮流方程所决定的相关性外,还存在着不同节点的同类型和不同类型随机变量之间的相关性,为评价电网规律扩大电力市场跨区交易等带来潮流随机波动的风险,采用蒙特卡洛模拟研究了考虑随机变量相关性的交流非线性概率潮流的统计特征,提出了能有效反映电网运行风险的电压、线路潮流、发电机无功功率的可能性和严重度指标。测试系统的仿真研究表明,随机变量的相关性对概率潮流的统计特征影响较大,不考虑随机变量的相关性会影响电网安全风险评估的准确度,而且需根据规划或运行的目的,从周期性或实时运行的角度分别建立系统模型,分析系统的薄弱环节。

We put forward the more effective indices of risk based assessment including the likelihood,severity of voltage magnitude,power flow,reactive power of generators,and studied the statistic feature of the nonlinear AC probabilistic load flow considering correlation by Monte Carlo simulation method,for the DC load flow or linear probabilistic load flow reflects the probabilistic feature of reactive power flow with great difference because of ignoring the correlation between stochastic variables.The simulation of the standard test system shows that the probabilistic dependency has a great influence on statistic feature,without considering that the risk assessment can be inaccurat.According to the aim of plan and operation,from periodic and real time operation,the system model is built to analyze the weakness point.