Comparison of MV-grid structures on fault ride through behavior of MV-connected DG-units

Nowadays the amount of distributed generation units is increasing rapidly. At this moment in the Netherland small combined heat and power (CHP) plants are most dominant. All CHP-plants are equipped with under-voltage protections which switch-off the CHP-plants at a dip of 0.8 p.u. with a duration of 100–200 ms. In this paper the voltage dip propagation of two existing distribution grid structures are compared. With the aid of simulations per grid structure it is determined what amount of CHP-plants disconnects during a voltage dip because of these settings.