Security Constrained Optimal Unit Commitment for Inverter Based Resources Penetrated Systems using AMPL Optimization Software

With the goal of reducing CO2 emissions into the atmosphere and goal of total de pendent on renewable energies to supply electrical demand, high penetration of renewable energy resources with inverter technologies has significantly increased
in electric power system. The high penetration of inverter based resources (IBR) in the electric grid in the past few years has created issues and challenges with respect to power system operation and grid stability. This report investigates the impacts of the high penetration of IBR on the system strength, especially the impacts of low system short circuit power and low system inertia. To mitigate these challenges, the thesis develops a security constrained unit com mitment (SCUC) model. The SCUC model includes extra security constraints for short circuit power and system inertia in order to guarantee stable and secure oper ation for the power network. The proposed SCUC simulates with alternating current (AC) power flow model with consideration of both active and reactive power, as well as maintaining volt age security and transmission capacity limits are considered. This thesis also models short circuit calculation in a mathematical programming language (AMPL) software, whose results are verified with known software (digsi lent powerfactory software). Two case studies with two test grids, four bus and fourteen bus test system respec tively, are analyzed to verify the effectiveness of the proposed SCUC model.