The objective of the project is to :
- investigate the performance of the system after 7 years operation
- implement design changes to improve the performance of the system
- continue experimentation on the subsystems
All the subsystems at the photovoltaic research installation on Fota island were analysed to investigate the extent of degradation after 7 years of operation. The electrical performance of the modules was not impaired, but there were frequent breaks in the cabling between them and widespread evidence of corrosion in the cable insulation. Cracks in the glass casings of photovoltaic modules caused short circuits between the cell and the frame. Varistors showed no degradation, and despite severe storms in the area, there was no lightning damage.
The inverter operated at an efficiency of 80% for input powers in excess of 5 kW direct current, but current and voltage waveforms showed dramatic changes depending on operating conditions, and the harmonic content of the current was greatly in excess of the 5% utility limit. Power factor correction capcitors further distorted the waveform. The noise of the inverter was well within recommended safety limits.
A battery testing facility has been constructed and installed to analyse the operation of an electrolyte agitated and nonagitated battery bank. The facility monitors voltage, current and temperature in cell cells, controls charging and discharging procedures, displays the measurements in graphical format and compiles statistical reports.
Comparison between a reference solar cell and a pyranometer proved that the reference cell was a better indicator of array performance. It was noted that incorrect sizing of subsystems, inverters and batteries in particular, had an adverse effect on the particular subsystem and on the overall system.
The 50 kWp PV system on Fota island ("Fota-voltaic" project) is one of the 16 PV pilot plants which were built in 1983. It is designed to supply electricity to a dairy farm on Fota Island. Excess energy from the PV system is sent to the utility grid. The system has been operating successfully since 1983 and operating data has been collected since January 1984.
The object of this contract is to continue the experiments at the PV installation and in particular to concentrate on experiments highlighted by the EC concerted actions groups. The main experiments will be :
1) PV Modules : Measurement of degradation, failure analysis of the modules, examination of cables, connectors, lightning protection equipment and grounding system.
2) Battery System Experiments : Compare two types of batteries (maintenance free and air bubbled lead acid), implement operation and maintenance procedures, test state of charge measuring equipment, measure cell variations in the batteries.
3) Inverter Experiments : Increase the efficiency by selecting the optimum component sizes (inductors and transformers) and by changing the operating conditions.
4) Data Monitoring : Continue evaluating the system, collect data to verify computer component models and system models.
5) Computer Model Experiments : Use the PV system in different power management modes to verify the power management models.
The "Fota-voltaic" Project is an ideal base to implement the recommendations of the concerted action groups and it is only by experimental verification that the theories developed by the concerted action groups can be accepted by PV designers.
Funding SchemeCSC - Cost-sharing contracts