Installation and Commissioning of a 100 kW Rooftop Solar PV Power Plant

Objectives: The grid connected rooftop solar photovoltaic system is gaining momentum. The feasibility study of its installation, testing, commissioning and grid connectivity issues is a must. The analysis of economic benefits in comparison with electricity charges as per utility and the payback period is prime requirement. The objective is to integrate solar power with grid and share a greater portion of solar power for the local use and contribute the solar power installed capacity of the nation Methods/Statistical Analysis: The paper gives a comprehensive study of site information, plant architecture, layout, single line diagram and test results prior to commissioning. An operation and maintenance sheet has been maintained to track the various parameters such as voltage, current and power both on DC and AC mains for individual inverters. The average V_DC, I_DC and P_DC has been found to be 620 volts, 32 Amps, 20 kW respectively from 11 am to 4 pm on bright sunny days. Similarly, V_DC, I_DC and P_DC were noted to be 440 volts, 27 Amps, 20 kW respectively.Findings: During light loading in the institute, the power flow from solar to grid was evidenced through net meters installed by the utility. This relieved the institute management to pay heavy electricity charges. The electricity charge by the utility for HT consumer was Rs.10 per kWh whereas the solar charges were paid at the rate of Rs. 6.4. This resulted in a significant cost saving. Application/Improvements: The power taken from grid during 11 am to 4 pm has been reduced from an average 45 kWh to 12 kWh per hour. The scheme is well suited for large commercial complex, residential buildings and offices. It can be implemented with battery back up in remote villages which has poor access to electricity.