Voltage Regulation (MV) by means of Q(U) — Simulation and measurement on a 12 MVA PV power plant

Open loop reactive power (Q) control function of the local voltage (U) measured at the inverter´s terminals is one possibility to comply with the BDEW´s MV grid regulations [1] in Germany, while other countries are considering to apply this solution as well. A better understanding of the stability limits for such a control algorithm is required when applying it to large PV plants or PV dominated grids. A dynamic RMS simulation model of a big PV plant including Q(U) control is developed. The model is compared with real life measurements in the PV plant and the local laboratory. Various study cases are further on performed in order to assess the voltage stability. An upper stability limit can be found depending on the grid connection parameters in the point of common coupling (PCC).