Effects of Mutual Coupling and Transposition of Phase Conductors on the Maximum Photovoltaic Penetration Levels in Distribution Feeders

The penetration level of solar photovoltaic (PV) generation in a distribution system is often limited by the constraint on voltage variation due to large intermittent power injection. This paper investigates the penetration levels of PV systems in distribution feeders by taking into account the mutual coupling effect between phase conductors. The equivalent circuit models for distribution line segments, including the grounding effect and the mutual coupling between phase conductors and the grounded neutral line, are applied to computer simulation. Two practical Taipower distribution feeders are selected for system analysis to study the maximum PV penetration with the proposed precise modeling of the feeder network. The increase of allowable PV penetration by executing the transposition of phase conductors to improve the three-phase balance is also analyzed.