Distributed Monitoring of Voltage Collapse Sensitivity Indices

TL;DR

This paper introduces distributed algorithms for real-time calculation of voltage collapse sensitivity indices in smart grids, enabling scalable and accurate voltage stability monitoring without central coordination.

Contribution

It proposes novel distributed linear algorithms that compute voltage collapse indices using local measurements and neighbor communication, improving scalability and accuracy over existing methods.

Findings

Algorithms converge to centralized index values

Effective in a 39-bus system case study

Account for generator reactive power limits

Abstract

The assessment of voltage stability margins is a promising direction for wide-area monitoring systems. Accurate monitoring architectures for long-term voltage instability are typically centralized and lack scalability, while completely decentralized approaches relying on local measurements tend towards inaccuracy. Here we present distributed linear algorithms for the online computation of voltage collapse sensitivity indices. The computations are collectively performed by processors embedded at each bus in the smart grid, using synchronized phasor measurements and communication of voltage phasors between neighboring buses. Our algorithms provably converge to the proper index values, as would be calculated using centralized information, but but do not require any central decision maker for coordination. Modifications of the algorithms to account for generator reactive power limits are discussed. We illustrate the effectiveness of our designs with a case study of the New England 39 bus system.