Development of Equipment for Monitoring PV Power Plants, using Virtual Instrumentation

In this work is introduced a system for monitoring the performance of PV power plants using the virtual instrumentation concept. It will use a hardware based on the National Instruments SCXI system and as software the Lab VIEW graphical programming package. The equipment is capable of real time signal measuring giving information about the performance of the PV power plant, as well as of the energy quality generated by it. Additionally, the equipment can also be used for measuring ambient variables like solar radiation and ambient temperature and for analyzing the energy quality of conventional electricity grid supplied to typical loads in commercial and residential sectors. The equipment was used during one year for monitoring both, the performance and the energy quality of a PV power plant, interconnected to the local grid under the BIPVS (building integrated photovoltaic systems) concept, in order to test its performance and reliability. The results indicated that the reliability and the accuracy of the monitoring system is excellent and than the tested PV power plant fulfilled the national and international quality standards demanded for PV generation. A description of the monitoring system as well as the daily irradiation in Bogota for every month of year 2005, is included in this paper. The behavior of the parameters characterizing the energy quality (percentage of the total harmonic distortion %THD, harmonic components, frequency, voltage of the PV system, flicker and power factor) are also reported