Transient stability analysis and improvement in microgrid

With the growing demand of electricity, deployment of microgrid is becoming an attractive option to meet the energy demands. However, a grid connected microgrid suffers a crucial stability issues during a fault in utility grid. For stable operation of microgrid during fault in grid, islanding operation is generally adapted. In this paper transient stability of the microgrid is analyzed during fault in utility grid and islanding condition. Due to the low equivalent inertia of the microgrid, rate of change of frequency of the islanded microgrid is very high. Two types of load shedding schemes are proposed to maintain frequency stability in microgrid i.e. Under Frequency Relay Based Load Shedding and power mismatch based Load Shedding and their results are compared. The simulated microgrid comprises a mix of hydro turbine generator, wind turbine generator and a photovoltaic cell as source and the loads consist of a combination of induction motor and static loads. For validating the obtained results simulations are performed in ETAP for five different cases, each incorporating different combinations of generators.