System Strength Constrained Economic Dispatch Model for a Renewable Embedded Power System

Due to the fast growth of renewable energy technology, the electric power system is currently comprised of various renewable sources of energy. Renewable energy incorporation into the existing grid diminishes system strength at the point of common coupling, compromising grid reliability and security. The Short Circuit Ratio (SCR) is a commonly used metric for determining the strength of a system. To reduce voltage loss and to ensure effective operation of the protective devices during fault conditions, a minimum value of SCR is mandatory. In the case of high renewable penetration, this paper proposes short circuit ratio constrained economic dispatch to ensure power grid safety. Here, we formulate an optimization problem subject to various practical constraints, which is solved in GAMS using a quadratic programming model. GAMS provides us with the results of the power sharing of the generators. The obtained results are evaluated using a modified IEEE 39 bus test system in DIgSILENT PowerFactory. Load flow and short circuit analysis done in DIgSILENT PowerFactory proves the validity of the simulation results. The results satisfy the SCR constraint in addition to fulfilling other constraints.