Estimation of Transmission System Power Transfer Capability at Competitive Renewable Energy Zones

Estimation of Total Renewable Power Transfer Capability (TRPTC) out of Competitive Renewable Energy Zones (CREZ) is a critical piece of information for transmission planning assessments, generation interconnection studies and reliable operation of interconnected power grids. Over the recent years, significant decommissioning of fossil-fueled power plants and increase in interconnection of Renewable Energy Resources (RERs) have resulted in several challenges in system operations due to variations and uncertainties included in the nature of these resources. Sudden and dramatic variations in output of RERs in conjunction with lack of sophisticated/sufficient VAR support in CREZ have directly impacted the system strength at their Points of Interconnection (POIs), and consequently, the system’s voltage stability. To investigate this impact, a few Short Circuit Ratio (SCR)-based methods were proposed and utilized to assess the system strength in CREZ. In this paper, we developed a SCR-based approach to estimate the TRPTC. More specifically, the newly developed Site-Dependent Short Circuit Ratio (SDSCR) methodology is utilized to estimate the TRPTC with respect to the NERC TPL-001-4 Standard. Accuracy of the TRPTC estimation using SDSCR methodology is illustrated and verified through comparative simulations studies versus other SCR-based methods.