Abstract
The paper develops a method for solving time-series power flow for unbalanced distribution power systems equipped with on-load tap changer and photovoltaic (PV) power generation. The proposed PV control is developed using a fuzzy logic controller. When the reactive power of the PV inverter is not enough, tap-up or tap-down signals are sent to the on-load tap changer to control the voltage. The Lagrange function is implemented to predict the initial values of voltage magnitudes and phase angles during the simulation process. These initial values are corrected using power flow routine that adopts the forward/backward analysis method. The IEEE-123 node test feeder is used to assess the validity of the developed continuous power flow solution. The results are compared with the traditional quasi-static time-series solution without prediction scheme. The simulation results prove that the developed time-series model has superior performance. The effects of PV penetration and voltage regulator on the method performance and tap setting are also investigated.