Fast selection of N-2 contingencies for online security assessment

TL;DR

This paper introduces an efficient algorithm for identifying critical N-2 contingencies in power grids, significantly reducing the analysis needed for online security assessment by filtering out safe contingencies quickly.

Contribution

The paper presents a novel iterative filtering algorithm that certifies the safety of most N-2 contingencies with complexity similar to N-1 screening, improving efficiency in power system security analysis.

Findings

Certifies 99.9% of contingencies with two iterations

Reduces analysis complexity to N-1 screening level

Effective on a realistic Polish power grid model

Abstract

We propose a novel algorithm for selection of dangerous N-2 contingencies associated with line or generator failures. The algorithm is based on iterative filtering of the set of all possible double contingencies. It is certified to identify all the dangerous contingencies, and has the complexity comparable to the N-1 contingency screening. Tests performed on realistic model of Polish power grid with about 3000 buses show that only two iterations of algorithm allow one to certify the safety of 99.9% of all double contingencies, leaving only 0.1% of the most dangerous ones for direct analysis.