Design of On-line Monitoring System for Grid-Connected Photovoltaic Power Plants

This paper describes the design of an on-line monitoring system for grid-connected photovoltaic plants. The proposed system consists of a meteorological data collection system for measuring meteorological parameters (e.g. irradiance, ambient air temperature, etc.), a set of data collection boxes for measuring electrical parameters (e.g. DC and AC current, DC and AC voltage, DC and AC power, etc.) and a PC. The collected data have been transmitted to the PC by two methods, wired transmission and wireless transmission. The software of the on-line monitoring system based on Lab VIEW (Laboratory Virtual Instrument Engineering Workbench) package is used to process, display and store the collected data in the PC disk. The on-line monitoring system was installed in a grid-connected photovoltaic plant for an on-site measurement in Qinghai province in China. The obtained results demonstrate that it has the ability for data collecting, processing and analyzing and it meets the measurement requirements of grid-connected PV plants.