Power Flow Analysis of Transient Stability in Microgrids used in Power Stations

With increasing distributed generations in the utility grid, the operation, control and stability of grid becomes challenging. Microgrid can be utilized to improve the transient stability of the grid in reducing the frequency and voltage fluctuations Solar PV and Batteries, which are a part of Microgrid, does not have any kinetic energy like conventional generators thus a controller is required to regulate constant power sharing. Droop control is the main concept where couples frequency with real power and voltage with reactive power and regulate frequency and voltage according to the variation in power with respect to load change without any communication. In conventional droop control, reactive power sharing is not accurate in case of inductive load and so virtual impedance is considered. The battery is used as a source for three-phase bidirectional converter and connected to grid through a switch. Different types of batteries can be connected in parallel to it with different converters. Bidirectional converters are used as it can work as inverter in discharging mode and it can work as rectifier in charging mode. It can work as microgrid and supply power to remote areas as there is no grid available. In the proposed control as battery is the source, battery’s SoC (State of Charge), capacity are taken in account with the conventional droop control in order to achieve accurate power sharing. The outputs of control is given as input to space vector PWM block which converts the voltage and its angle to time and gating pulses are given to the switches in the converter.