PNNL

Abstract

The electric power grid is increasingly prone to severe contingencies which degrade the reliability and security of the power system. Current practices assess the risk posed by contingencies though steady-state methods like N-1, N-2 and N-1-1 analysis. While these methods have been tested and used for decades, the increasing frequency of blackouts and major outages demonstrates that these methods do not fully capture the contingency risk. In other words, many contingencies exhibit phenomena, such as cascading failures, that go beyond steady state models. Unfortunately, the computational requirements of full contingency assessment with detailed models remains out of reach for the modern grid operator. To address this challenge, this paper explores the suitability of using steady-state, N-k analysis to identify a smaller set of contingencies that require detailed cascading analysis. The method is demonstrated on the IEEE 300 bus test system for N-1 and N-2 contingencies and a detailed analysis is provided to determine situations where N-k analysis correctly (and incorrectly) identifies the contingencies that require further analysis.