How the PV system is set up in a Schoolgen school
Schoolgen PV System Overview
The PV system installed at a Schoolgen school consists of 12 175W or 12 170W solar panels connected in two strings, with six panels on each string, or 12 panels in one string, to limit the input voltage to the inverter.
The positive and negative terminals of the strings are terminated at the DC side of the inverter, the device which converts DC power produced by the PV system to mains AC power. The AC side of the inverter is connected and synchronised with the local distribution board in the school. The system is grid connected meaning that during daylight hours the system produces electricity for use within the school.
The inverter used in the Schoolgen programme is a grid connected type inverter and is equipped with an isolating transformer to prevent system islanding [i.e. if the mains fails, the system automatically shuts down preventing back feeding into the mains system].
Electricity generation data from the inverter is captured and uploaded to the internet by a purpose designed interface device called the Hot-E box. The Hot-E box is connected to the Schools LAN (local area network), and data is pushed to the remote Schoolgen FTP server where it is converted into daily, weekly, monthly and yearly generation graphs on the Schoolgen website.
Figure.1 Typical circuit diagram the 2kW PV system installed at a Schoolgen school
Students are able to view and download the electricity generation data directly from the Schoolgen website as part of in-class experiments and projects.
More technical information regarding the PV system set-up used in Schoolgen can be found in the Schoolgen technical casestudy.
