Studies On The Effect Of Plug In Of Distributed Generations On Voltage Sag Of Distributed Network

Nowadays the load of electric power becomes larger and larger along with the change of structure of the world energy. So it is necessary to develop the Distributed Generation (DG) rapidly to insure the secured power supply and optimize the power supply model. The DG is able to bring positive variation to the modern power system in terms of environmental protection, energy conservation, long-distance power transmission and power distribution reliability. The operational reliability will be affected when a large number of DGs are installed in. And also the complexity of the power system will greatly increased. One of the problems is that the inter-connected of DG will affect the voltage sag in distributed network.Be aimed at this, in this paper, the basic concept, characteristic parameters, damage and mitigation methods which related to voltage sag are firstly introduced and then, a voltage sag analysis model of distribution network containing DGs is built and simulated based on EMTDC/PSCAD. The voltage sag characteristics are extracted precisely from the simulation results by the Moving Window Method. Simulation results show that interconnecting inverter-based DG to distribution network can mitigate the voltage sag to some extent. The control strategy, installed position and output power and of DGs also exert certain influences on voltage sag. All these conclusions are available for reference on mitigating voltage sag with DGs installed in the distribution network.