Evaluating the Impacts of Transmission Expansion on Sub-Synchronous Resonance Risk

TL;DR

This paper assesses how transmission expansion projects can influence the risk of Sub-Synchronous Resonance in power grids, using a novel two-step approach with outage and damping indices, demonstrated on the ERCOT grid.

Contribution

It introduces a graph-theory based SSR screening tool and a frequency-scan damping analysis to evaluate SSR risk impacts of transmission expansions.

Findings

Transmission expansion can increase SSR risk in certain grid configurations.

The proposed method effectively quantifies SSR risk changes due to expansion.

Application to ERCOT grid illustrates practical utility and insights.

Abstract

While transmission expansions are planned to have positive impact on reliability of power grids, they could increase the risk and severity of some of the detrimental incidents in power grid mainly by virtue of changing system configuration, consequently electrical distance. This paper aims to evaluate and quantify the impact of transmission expansion projects on Sub-Synchronous Resonance (SSR) risk through a two-step approach utilizing outage count index and Sub-synchronous damping index. A graph-theory based SSR screening tool is introduced to quantify the outage count associated with all grid contingencies which results in radial connection between renewable generation resources and nearby series compensated lines. Moreover, a frequency-scan based damping analysis is performed to assess the impact of transmission expansion on the system damping in sub-synchronous frequency range. The proposed approach has been utilized to evaluate the impact of recently-built transmission expansion project on SSR risk in a portion of Electric Reliability Council of Texas (ERCOT) grid.