An unthinkable application of photovoltaics is the power supply of high voltage circuit breaker on Terna power lines.

As a matter of fact, although through the high voltage wires of the power lines pass power of electric megawatts at 60KV and more, in practice it is difficult to power the electric motors of the circuit breakers and auxiliary services deriving energy from the power line itself.

Moreover, these power lines are far from the low voltage grid and therefore it becomes expensive to supply power to these services. In addition, the circuit breakers must also be operational in the event of black-out of the main network and must therefore be equipped with electric batteries or generators.

In these conditions it becomes convenient to feed these services with a stand-alone photovoltaic system.

Western Engineering has designed and built, on Terna specifications, a controller for charging batteries from photovoltaic modules that has been installed by PLC SpA at the pylon that realizes the 60KV derivation for Fincantieri at the Castellammare – Sorrento power line.

This controller, managing to charge nominal 108V batteries (9 blocks of 12V AGM batteries for series cyclic use) is unique of its kind. There is no other product on the market that can charge high voltage photovoltaic batteries for Terna standards. The controller implements two independent MPPT channels in a buck – converter configuration with IGBT at 600V with a 25A channel charge current (total charge current in 50A battery for a total power of 5500W).

This photovoltaic application has allowed considerable energy savings for Terna and, thanks to our work, can easily be replicated in many other pylons where similar situations can arise.