Temperature Effects on DC Cable Voltage Drop in Utility Scale Rooftop Solar PV Plant Based on Empirical Model

Abstract

This paper discusses the effect of losses occurred due to rise in temperature in determining the optimal capacity of DC cable for a Solar Photovoltaic (PV) system application. An optimization is considered to address the existing trade-off between cost of losses due to the voltage drop and its investment cost. The main outcome of the model is the optimal DC cable capacity for a given PV system, as well as the relevant optimal DC cable sizing with respect to voltage drop. An experimental result of 250 kW Solar PV system installed at a latitude of 23.029° N and longitude of 72.577°E is used to determine the effect of temperature rise on voltage drop of dc cable at outdoor conditions. This paper presents an empirical model to determine the effect of voltage drop by temperature through experimental data. In this work a focus is made on th effect of temperature on DC cable and its solution towards performance guarantee as well as improvement in generation forecasting. This study is carried out to find on site dc voltage prediction with minimum error and provides prediction based on empirical formula. The model results reveal that, by installing the dc cable in outdoor conditions of semi-arid places like Gujarat, and other arid regions, where average ambient temperature is about 30°C- 35°C and in summer maximum is above 40°C and there is an increment in voltage drop of about 12 to 18 % with respect to standard test condition. By choosing the proper cable size we can save 2400 kWh to 5400 kWh annually which reduces annually 1200kg to 3000 Kg Co2 and 300Kg to 700 Kg coal could be prevented annually. With optimal design of DC cable we can reduced the cable loss below 1 % which is at par and it generates 1.8 to 2.4 times more revenue.