Efficient and Robust Power System Contingency Screening

Abstract The increasing contribution of renewable resources and the electricity market liberalization creates variety of scenarios’ that may lead power systems close to their operation limits. Online dynamic security assessment of the power systems is thus needed, in order to provide operators with a clear insight of the present system state. The online application of dynamic security assessment to a network requires fast and accurate methods to screen contingencies. This paper introduces a fast and robust contingency screening method. Based on the most current system snapshot, a list of credible contingencies are simulated by using Adaptive step-size Differential Transformation method (AsDTM) and severity indices are evaluated as the weighted sum of squares of error from the simulation results of both state variables and complex bus voltages and normalized for each contingency in the list. Based on these severity indices critical contingencies are screened and listed. This novel approach not only reduces the time performances but also improves the accuracy of resulting indices The proposed method is tested on IEEE 9-bus and New England 39-bus test systems. Capered with classical differential transformation and Fourth Order Rangkutta(Rk4) based simulation and contingency screening methods, the proposed method improves the performance speed by 35% − 92.26% for IEEE 9 bus test system and 35.29%- 90.77% for 39bus test system respectively. Therefore, the simulation and analysis results reveal that the proposed method is faster, robust and can be used with an online dynamic security assessment tools. .