Power flow control in a distribution system through an inverter interfaced distributed generator

This paper discusses power flow control in a radial distribution system in which a distributed generator (DG) is connected. The DG energy source is assumed to give a constant dc output voltage and is connected to the distribution bus through a power electronics based voltage source converter (VSC). The VSC controls the voltage of the bus to which it is connected and injects the required amount of real and reactive power into the ac system. A modification of Newton Raphson load flow is proposed which can calculate the real and reactive power that needs to be injected by the DG based only on the measurement of local variables. It has been shown that the proposed algorithm is capable of handling a change in the load or voltage sag in the ac supply system. The method is validated through simulations performed using PSCAD/EMTDC Version 3.0.7.