Baseline energy assessment to investigate performance indicators for large scale photovoltaic power plant in India

Many of the solar PV power plants installed in the last decade are witnessing numerous mid life challenges. Operation and maintenance portfolio of solar PV power plant has growing significance considering the increasing gigawatt of installations across the world. This paper investigates the field level performance indicators from a 50 MW Solar photovoltaic power plant (SPV) in South India. Majorly, specific yield and performance ratio from four different blocks of the have been evaluated based on the data measured from March 2020 to February 2021. Conclusions are derived from the deviations and abnormalities in energy generation, and their possible reasons are summarized. There is a shortfall of -5.3% in the actual energy generation from the committed energy generation. Further detailed analysis of the block wise specific yield comparison indicated that there is a considerable difference in the specific yield among different blocks. Each block has 5 central inverters. The average annual yield from 20 inverters was 1437 kWh/kWp, with maximum and minimum being 1521 kWh/kWp and 1351 kWh/kWp, respectively. The average value of the AC side performance ratio for the entire 50 MWac power plant as per data obtained was 70.40 %, with a maximum value of 79.71 % (July 2020) and a minimum value of 62.83 % (Dec 2020). The deviations in the irradiance measurements with reference to a calibrated sensor has also been evaluated. The possible reasons for the shortfall in performance are presented. The recommendations of this study will be useful inputs for the operations and maintenance professionals in the solar industry to develop an Al-based tool for systematic intervention in performance-related problems in the SPV. Moreover, it provides insights to the design team to optimize the system configurations of their power plants.