# Understanding the Inefficiency of Security-Constrained Economic Dispatch

## TL;DR

This paper introduces the 'price of security' metric to quantify the economic inefficiency caused by security constraints in economic dispatch, analyzing its behavior in simple and complex power network scenarios.

## Contribution

It proposes a novel metric for security-related inefficiency, analyzes its worst-case and typical behavior, and provides empirical validation on test cases.

## Key findings

- The price of security varies with generation and demand distribution.
- Explicit worst-case input scenarios maximize the price of security.
- Experimental results confirm analytical insights across test cases.

## Abstract

The security-constrained economic dispatch (SCED) problem tries to maintain the reliability of a power network by ensuring that a single failure does not lead to a global outage. The previous research has mainly investigated SCED by formulating the problem in different modalities, e.g. preventive or corrective, and devising efficient solutions for SCED. In this paper, we tackle a novel and important direction, and analyze the economic cost of incorporating security constraints in economic dispatch. Inspired by existing inefficiency metrics in game theory and computer science, we introduce notion of price of security as a metric that formally characterizes the economic inefficiency of security-constrained economic dispatch as compared to the original problem without security constraints. Then, we focus on the preventive approach in a simple topology comprising two buses and two lines, and investigate the impact of generation availability and demand distribution on the price of security. Moreover, we explicitly derive the worst-case input instance that leads to the maximum price of security. By extensive experimental study on two test-cases, we verify the analytical results and provide insights for characterizing the price of security in general networks.