DECENTRALIZED VOLTAGE CONTROL IN 20 KV DISTRIBUTION GRIDS BY CONTROLLING REACTIVE POWER OF INVERTERS

Decentralized generation units are capable to influence the voltage in the 20 kV-distribution grid by a controlled reactive power feed-in. In this paper different control characteristics and their impact on the 20 kVmedium voltage (MV) grid are presented. The focus in the simulation scenarios was the comparison of an active factor cosφ(P)-control characteristic with a reactive power/voltage characteristic Q(V). For the simulations a real 20 kV-MV-district was reproduced. The photovoltaic generation and load profiles were measured in this district and used in the simulation. So the simulation results could be aligned with the reality for the used cosφ(P)- and Q(V)-control mode and the effects of different parameterisations have been calculated. Furthermore, the influence of the control modes on the grid losses over a whole year could be considered. In addition, it was differentiated between a workday and weekend to cover different load situations. Due to this fact, this paper illustrates the simulation results for a single weekday in summer and winter. The investigation shows that decentralized generation units operating with a reactive power control can strongly impact the voltage level in a MV-district.