IMO Technical Brochure
www.imopc.com
5
A Photovoltaic (PV) power system primarily converts sunlight directly into electricity using a photovoltaic cell array. The conversion of the solar
radiation into electric current is carried out using the photoelectric eect found when some semiconductors that are suitably “doped” generate
electricity when exposed to solar radiation.
As an individual PV-cell gives a relatively low output, a number of PV-cells are connected in series to supply higher voltages and connected in
parallel in order to oer higher current capability. These cell arrays are referred to as PV-panels, and a number of interconnected panels are
referred to as PV-strings. If there is a requirement for increased capacity then a larger system can be constructed whereby the PV-strings are
connected in parallel to form a PV-array that gives a DC output current equivalent to the sum of all the PV-string outputs.
The main advantages of photovoltaic (PV) electricity generation are as follows:
• no fossil fuel usage and subsequent emission of pollution
• no nuclear fuel usage and disposal or storage of radioactive materials
• local distributed generation where needed
• installed system reliability and extended life
• reduced operating and maintenance costs
• ease of upgrading and replacement if necessary due to modularity of installation
When considering PV panels it is important to ensure that the units comply with all relevant standards for both electrical performance and for
building requirements. It is recommended that, where possible, they comply with either IEC 61215 or IEC 61646, depending upon the structure
of the cells. Once chosen the panels should be mounted in a location that maximises their exposure to sunlight for as long as possible and limits
the possibility of shading, or future potential shading.
An inverter should be chosen to match the overall power capacity of the PV array, and like the arrays, it should operate as eciently as possible.
When considering the inverter, one using a Maximum Power Point Tracking (MPPT) system is preferential as this is a technique that grid
connected inverters use to get the maximum possible power from one or more photovoltaic devices.
Where the PV installation is tied into the domestic grid system then the rules and procedures designated in G83 should be referred to and
followed by a competent installer who is associated with a suitable accreditation scheme such as MCS.
Introduction to PV design
IMO
IMO
PV Array
DC Isolator
DC / AC Solar Inverter
AC Isolator
House distribution unit
and meter
Solar Panel Rapid
Shutdown Solution
Rapid Shutdown
Emergency Switch
(at ground level)
Keeping Solar Safe