EL L I IN N LV D DI ISTRI IBUTIO ON N NETW WO OR RK KS S BA ASE ED D ON N THE E V VOL LT TA AGE E O OPERA AT TI ION NAL L M MAR RG GI IN

In this paper, an approach to the critical photovoltaic penetration level is presented, based on the capacity of a DSO to regulate the voltage in a MV/LV substation by means of Off-Load Tap Changers. The performance of offload tap changers to cope with an increasing amount of PV is investigated, by introducing the concept of the Voltage Operational Margin: the range of voltage where the tap can be set in order to avoid under-voltage or over-voltage.