An analytical model for evaluating the effect of voltage control devices to compensate PVs output power fluctuation

Voltage control of distribution feeders would become difficult by large scale interconnection of photovoltaic (PV) power generation systems. Application of tap control device (LRT: Load Ratio Transformer, SVR: Step Voltage Regulator, etc.), STATCOM (STATic synchronous COMpensator) and PVs´ reactive power are considered as countermeasures for proper voltage control of the distribution feeders. There are hourly voltage change and short-time voltage change. Proper countermeasure should be selected for each phenomenon considering the cost-benefit. In this paper, we propose an analytical model for efficacy limit of tap control device and required capacity of STATCOM for output power fluctuation of photovoltaic power generation system. In the calculation example, the efficacy limit of tap control device and the required capacity of STATCOM are shown by the proposed model and the costs are also evaluated by relative comparison.