Design considerations and performance evaluation of the Virginia Integrated Solar Test Arrays

The Virginia Integrated Solar Test Arrays (VISTA) facility was built and is operated by Virginia Power. This 60 kWp (rated) AC photovoltaic (PV) facility consists of three separate 20 kWp AC subfield of different designs providing an opportunity to compare full systems of various tracking mechanisms and cell technologies at one site. Subfield A is comprised of polycrystalline modules arranged on two-axis tracking structures. Subfield B is comprised of polycrystalline modules arranged on fixed-axis structures. Subfield C has single crystal modules and is fixed. At the VISTA facility, commercial-size PV arrays have been interconnected with the grid. This facility has been operational since December 1985, and on-site data collection is ongoing since June 1986. In addition to the design perspective and the system description, the summary of the on-site data collected between June 1986 and March 1987 are presented. It is observed that, over this period, the array and power conditioning until power-conditioning-unit (PCU) efficiencies match closely with design values, and the energy availability factor ranges from 34.80% to 39.99%