Transformerless Power Plant
Hemau, in the district of Regensburg Gernmany, has seen the commissioning of the first megawatt station built by Sputnik Engineering, a Swiss inverter manufacturer. The 632 photovoltaic (PV) plant was installed on open land by SolaStrom Systems GmbH, a system integrator based in Augsburg.
At the new site the usual low-voltage transformer (400V) is unnecessary because two of a new type of SolarMax central inverter, the SolarMax 330C-SV, feed the power directly into the transformer on the medium-voltage grid. The transformerless technology of these new inverters has enabled Sputnik to cut both the size and the weight of the system by half compared with the previous models. At the same time, Sputnik's developers have boosted efficiency by 1.5 percent and lowered costs as well. The investor and system operator expects that the system will already be amortised in seven years. The company receives from the local grid operator the price guaranteed by Germany's Renewable Energy Act, 31.94 cents for every kilowatt hour of solar power produced.
The PV system in Hemau is monitored by Sputnik's communications network, MaxComm, together with its internet-based data logger MaxWeb. This is the first time that Sputnik has equipped its data logger with the newly developed software option MaxRemote. It ensures that as soon as the grid operator requests a reduction in power, the inverter automatically reduces its output. This prevents short-term overloads. Starting this year, this remote-controlled reduction in output has been required by both the Renewable Energy Act as well as the new guideline for the connection and parallel operation of generation plants issued by Germany's Federal Association of Energy Suppliers and Water Utilities (Bundesverband der Energie- und Wasserwirschaft).
"What was especially exciting for me about Sputnik's new megawatt station was its innovative technology and complete package," according to SolaStrom managing director Gerald Schubert, who is convinced of Sputnik's quality and service and has been installing SolarMax products since 2003. This year alone, SolaStrom will install SolarMax inverters with a total capacity of three megawatts.
