Robust Design of North American Power Grid to Mitigate Cascading Failures

Abstract

Catastrophic cascading system failures such as the August 13th Blackout of 2003 highlight the vulnerability of the North American power grid, and emphasize the need for research to mitigate failure events. The incorporation of robust design, the insensitivity of system performance in the presence of noise (or uncertainty) from both internal and external sources, into existing and future power grid design strategies can increase system reliability. This paper presents a high-level topological network approach to power grid robust optimization as a solution for designing against cascading system failure. A mathematical model was created representing a standard power grid network consisting of generation and demand nodes, as well as node connections based on actual topological transmission line relationships. Each node possesses unique power generation or demand attributes, and various network connection configurations are examined based on system demand requirements. In this model, failure events are initiated by the removal of a single network connection, and remaining loads are redistributed throughout the system. Cascading failure effects are captured when the existing network configuration cannot support the resulting demand load, and transmission line failures continue propagate until the system again reaches a steady state, based on remaining nodes and connections. The primary goal of this research is to facilitate an understanding of design trade-offs between system robustness and performance objectives. In this research, robustness is defined as the resilience to initiating faults, where a robust network has the ability to meet system generation requirements despite propagating network failures. Primary performance objectives are total system cost and the ability to satisfy network demand after a failure, while robustness is represented as the lack of variability in the amount of demand which is satisfied after a failure. By understanding network reactions due to cascading failures, as well as performance trade-offs required to mitigate these failures, reliability in power grid systems can be increased.