Development of a Tool for Performance Monitoring, Analysis and Fault Detection in Solar Photovoltaic Plants

Abstract

The input quantity, solar irradiance, for a solar PV plant is beyond human control and varies with time, various seasons, location of the plant etc. Also the changing weather conditions change the operating temperature of the PV panels. Hence the performance monitoring strategy for a solar PV system, unlike fossil fuel based plants, must essentially include a model to estimate the expected output power for prevailing weather conditions and input solar power. Apart from these considerations, there can be considerable loss of D.C. power if the load resistance across a PV device is not optimal for the prevailing conditions. Without such model based performance monitoring strategy, potential faults in PV plants may remain unnoticed and unattended for long periods which result in lower production and loss of investment. In this project, a circuit based mathematical model for the PV Panel/array has been developed in LabVIEW software which can estimate the optimal expected power for the given set of solar irradiance and temperature values. The model also estimates the optimal load resistance that has to appear across the installed PV Panel/Array to tap the maximum output power and efficiency. Initially this model has been analyzed, tested and validated for a single solar cell using the data from the manufacturer’s data sheet. Revisions and improvements in the initial model have been implemented to develop a model more robust, accurate and with useful features particularly for the development of a SCADA system for PV panel performance monitoring. The validation of this model has been achieved using datasheet as well as by comparing the values measured from a PV panel operating on a simulator setup. A mathematical model for estimating the hourly solar irradiance at a given place, time and tilt angle of the PV panel has also been developed. Finally the developed model has been integrated with a SCADA software and a GUI has been developed for performance monitoring and fault detection in a PV panel. The SCADA system is capable of acquiring the measured parameters from the PV panel for real-time monitoring. It includes features like alarms, trends and reports for comprehensive monitoring and fault detection. RF based wireless data (measured values from PV panel) transmission has been implemented and tested using MSP 430 micro-controller and RF module pairs as an effective remote monitoring strategy.