配電系統の切替や変化を考慮したPV進み定力率値の選定

抄録

Since high penetration of photovoltaic (PV) power generation has realized, vector-LDC tap control on distribution transformer and constant leading power factor operation of PV are becoming recognized as hopeful mitigation methods for voltage deviation due to PV output fluctuation. Although the authors had proposed those two methods, various structures of distribution system were not considered. If number of feeders under one distribution transformer is changed by such as temporary network structure or demand growing process, optimal leading power factor of PV must be changed. Since vector-LDCs are owned by network company and their number is small, their setting can be changed easily. However, PVs are owned by customers and their number is large, so change of their power factor setting is not so easy. Then, how uniform PV power factor should be chosen?

The paper considers two distribution system structures: 5 feeders under a distribution transformer, and 1 feeder under a distribution transformer. In the former case optimal PV power factor is around Q =-0.2P, and in the latter case it is around Q =-0.4P. Four cases by the two system structures and the two PV power factors are examined, when slow or fast PV output change is given, using “CRIEPI V method” simulation tool.

As the result, only “5 feeders under a distribution transformer with PV operation at Q =-0.4P case” has shown ill voltage regulation caused by over compensation on reactive power control. Thus, light constant leading power factor around Q =-0.2P is proven as favorable for PVs, even when temporary structure or demand growing process are considered.