Optimisation of Photovoltaic Plants : Economic Cable Sizing

Over-sizing the cross section of a cable beyond the result of voltage and current theoretical calculations is, in most of cases, a worthwhile investment that is easily amortised by the electricity bill savings (reduction of Joule losses). In the case of a photovoltaic (PV) installation, the allocated price for energy (feed-in tariff) is much higher than the market price, getting amortised much faster.

Together with an improved profitability of the project, there are additional advantages when using bigger cable sections:

• Electric lines with lower load, which improves the lifespan of the cables;
• If the plant is to be enlarged, the cables can be maintained;
• A better response to potential short-circuits;
• Improved Performance Ratio (PR) of the plant;
• Associated environmental benefits (CO2 emissions and other)

This article shows the benefits on a 100 kW photovoltaic installation.

The author, Lisardo Recio, is Product Manager at Prysmian Cables & Systems, a partner organisation of Leonardo Energy. He is in charge of the technical training in the company and writing articles.

Optimal Cable Sizing in Photovoltaic Systems