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

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.

Electrical Damping Assessment and Sensitivity Analysis of a Liquefied Natural Gas Plant: Experimental Validation

“…In the literature the first studies focused on the torsional instability risk assessment are related to the Sub Synchronous Resonance (SSR) phenomenon [4][5][6][7]. In [4], the generator damping, measured at no load condition, is used as an index value to define the risk.…”

“…In [5] the compensation impact factor is 2 of 26 used to detect SSR risks in the case of series compensated transmission lines. In [6] the impact of the transmission expansion on the system damping is evaluated using the frequency-scan approach. In [7] the SSR risk is detected comparing the electrical damping with the modal damping.…”