Turnkey solutions for photovoltaic plants

The company had already been known for their water and wind power plants on the Portuguese market of renewable energy for two decades. With a solar energy park in Ferreira, Alentejo in the south of Portugal, they now also count on the energy supplying power of the sun – without neglecting the destructive power of a thunderstorm.

“With a performance of 18 megawatts, our plant will cover 70 percent of the annual consumption of Ferreira’s inhabitants – supplying clean energy,” says Tiago Barata of Grupo GENERG. The ecologically sound energy is generated by a total of 35,000 solar panels. A large-surface plant like this, however, is vulnerable. During a thunderstorm it bears the risk of damage, due to power surge caused by atmospheric discharge, resulting in profit cuts.

To counteract this risk, the plant needs a self-contained lightning protection concept granting the required security for electronic and electrical devices. CME, Portuguese installers of the plant in Ferreira, specifically requested a time and cost saving solution for the connection and switching of all solar panels. At the same time, they required protection of the cables against failure due to short-circuit, atmospheric discharge causing power surge and disconnection of the DC power line of the solar modules.

“Coming up to the CME requirements we tailored PV boxes, each connecting four or five solar modules, depending on the type,” João Polónio of Weidmüller explains the customer-specific solution. The integrated surge protection modules PU II, especially suitable for applications in the field of photovoltaic, guarantee reliable protection of the inverter. A Y-connection, consisting of two varistors and one gas-filled arrester to the earth potential, forms part of this concept. This circuit is absolutely free from leakage current and does in no way affect the monitoring of the insulation. Overcharge of the surge protection thus is effectively prevented.

“This precisely adapted solution convinced us that Weidmüller would be the ideal partner for our project,” Antídes Amorim of CME says. “The Weidmüller engineers showed flexibility in responding our needs

and developed a prototype, perfectly in accordance with the requirements of our project.” For this reason, Grupo GENERG will count on the partnership with CME and Weidmüller for further steps of the solar

energy project. “We are very content with the technical solution and service offered by Weidmüller and CME,” Barata says. “Therefore we will be glad to continue this prospective partnership.”

Surge protection is highly recommendable

The IEC 60364-7-712 standard, recommending surge protection for energy supply lines in photovoltaic plants, has been valid since March 2008. Weidmüller offers a wide range of plug-and-play solutions for the

protection of photovoltaic plants against damage caused by lightning. Class II surge protection modules are integrated in pre-assembled housings, in accordance with protection class IP65 and tested by an

accredited high-voltage testing laboratory. The so-called PV boxes guarantee protection of the inverter against power surge within DC and AC circuits. For problem-free and efficient installation the housings are equipped with standard MC4 connection systems. Prepared like this, the PV boxes serve as plug-and-play solutions that, after comprehensive information by the specialists of the Weidmüller department CSS (customer-specific solutions) can be adapted to any customer’s requirements.