Transmission Line Overload Risk Assessment for Power Systems With Wind and Load-Power Generation Correlation

In the risk-based security assessment, probability and severity of events are the two main factors for measuring the security level of power systems. This paper presents a method for assessing line overload risk of wind-integrated power systems with the consideration of wind and load-power generation correlation. The established risk assessment model fully considers the probability and the consequence of wind uncertainties and line flow fluctuations. The point estimate method is employed to deal with the probability of line overload and the severity function is applied to quantify line flow fluctuations. Moreover, with the Cholesky decomposition, the correlation between loads and power generations are simulated by the spatial transformation of probability distributions of random variables. In addition, Nataf transformation is used to address wind resource correlation. Finally, the line overload risk index is obtained, which can be used as an indicator for quantifying power system security. Numerical results on the modified IEEE 30-bus system and the modified IEEE 118-bus system show that the types and the parameters of the wind speed distribution would affect the risk indices of line overload, and the risk indices obtained with the consideration of wind resource correlation and load correlation would reflect the system security more accurately.