Dynamic Grid Voltage Support from Distributed Energy Resources during Short-Circuits

Grid codes are consistently updated in order to increase the operation efficiency of the power system. In many utilities, Low-Voltage-Ride-Through (LVRT) capability of Distributed Energy Resources (DERs) is nowadays a grid code requirement, according to which DERs should stay connected to faulty grid and support the voltage. This paper intends to illustrate the benefits gained from the LVRT capability of DERs to support voltage dynamically under short-circuit conditions. Both synchronous generators and inverter-interfaced DERs are included in the analysis, initially as single grid-connected units and subsequently as generating units connected to a benchmark distribution system. The importance of the synchronous machines voltage regulator parameters and that of the inverter-interfaced DERs’ control system is highlighted. Local versus dispersed integration of DERs, the line type of the distribution feeder and the DERs regulator/controller operation are shown to play important role in grid voltage support during short-circuits if DERs are operating independently or together in a distribution system. Relevant conclusions occur from the simulation results.