A grid-interactive photovoltaic uninterruptible power supply system using battery storage and a back up diesel generator

This paper presents a practical implementation of a grid interactive photov oltaic Uninterruptible Power Supply (UPS) system using battery storage and a back up diesel generator. The system incorporates 2.5 kWp of photovoltaic arrays, a 10 kVA power conditioning unit capable of operating in both inve rting and charging modes, and a 300-Ah battery bank. Two such systems were installed in two Indian cities. The project was implemented using soft loan s available in India through a World Bank Loan for photovoltaic market deve lopment. The system has been working satisfactorily since May 1997 and has demonstrated the capability of the system to provide uninterrupted power, d emand side management function and load voltage stabilization in a grid whi ch experiences frequent blackouts and under/over voltage problems. Some res ults from the field installation are also included in this paper.