Voltage profiles resulting from the application of storage is shown in Fig. 7 for the bus at the end of the feeder where the change is more visible due to lower short circuit strength. At about 9 am, the overvoltage set point is crossed and the net exchange of power is now positive with a PV penetration of 111% (i.e. with a PV output of 1.73 kW while serving a load of 1.55 kW). This excess power is used to charge the battery; the battery power is shown in Fig. 8. At midday the PV power reaches approximately 2.93 kW and load is about 1.65 kW resulting to the increase in PV penetration to 177%. For C/20 charging rate, the charging continues up to about 3 pm when
the voltage drops below the threshold value. Fig. 9 shows that at this charging rate the battery capacity at 3 pm is not fully charged yet (SoC = 0.74). If the charging rate is increased to C/10, the reduction in the voltage rise is higher, as shown in Fig. 7, due to higher amount of power being consumed by the battery during the charging operation, as shown in Fig. 8. The SoC of the battery reaches at 0.95 at about 2 pm, which is the assumed full level of the battery, as shown in Fig. 9 and the voltage rises above the threshold at this time. This means that the storage has not been effectively used to take advantage of the full duration of the PV generation, causing a period when the voltage rises above the threshold. Using the forecasted duration of the PV generation, some intelligent control can be devised to determine the correct charging rate of the battery to ensure that the PV is fully charged only when the voltage drops below the threshold value, and hence less amount of voltage rise will be experienced by the feeder. Fig. 7 shows such a scenario can be approximately achieved by setting the charging rate to C/13. The storage stops charging at about 3 pm, when the PV penetration was about 106% with a PV output of 1.63 kW and a load of 1.53 kW.