SMA America and UL Partner for Transformerless Inverter Workshop at Solar Power International

Free Training Focused on Safety with Ungrounded PV Systems

ROCKLIN, Calif., Nov. 10, 2010—SMA America continues to champion transformerless inverters with its recent partnership with Underwriters Laboratories® (UL) for “The Transformerless Inverter Workshop.” The free training session, which took place at Solar Power International in Los Angeles on Oct. 15, 2010, focused on how transformerless inverters in ungrounded PV systems can be safer than grounded arrays.

“This is the second time that SMA and UL, one of the world's most renowned product safety certification organizations, have partnered regarding transformerless inverters,” said Dave Wojciechowski, director of sales for SMA America. “Just this year, SMA helped UL develop the testing procedure for transformerless inverters, resulting in the expansion of the UL 1741 Standard of Safety to include the requirements of the IEC 62109 Standard.”   

During the workshop, which was attended by 100 influential solar industry and fire department personnel, keynote speaker Bill Brooks of Brooks Engineering provided a practical discussion on how ungrounded systems provide higher fault detection—and thereby increased safety--compared to traditional grounded arrays.

Fault detection features of SMA’s transformerless Sunny Boy 8000TL-US, Sunny Boy 9000TL-US, and Sunny Boy 10000TL-US inverters include the Riso Detector and Residual Current Monitoring Unit (RCMU). The Riso Detector checks insulation resistance prior to or during inverter startup and prevents operation if a fault is detected. During operation, the RCMU checks for fault currents. If fault currents are present, the inverter will automatically disconnect from the grid.

SMA’s transformerless inverters also boast unmatched weighted efficiencies of 98 percent (Sunny Boy 8000TL-US and Sunny Boy 9000TL-US) and 97.5 percent (Sunny Boy 10000TL-US), according to the California Energy Commission (CEC). The patented OptiTrac MPP tracking procedure and OptiCool™ active cooling system ensure that they reach these efficiencies, even when used in areas with high ambient temperatures. Moreover, the transformerless Sunny Boy TL-US weighs less than transformer-based inverters, making it significantly easier for installers to mount.

About SMA
The SMA Group generated sales of more than sales of 934 million Euro in 2009 and is the worldwide market leader for photovoltaic inverters, a key component of all solar power plants. It is headquartered in Niestetal, near Kassel, Germany, and is represented on four continents by 13 foreign subsidiaries. The Group employs a staff of over 5,500 (incl. temporary workers). SMA’s product portfolio includes the most comprehensive range of inverters on the market, offering a compatible inverter for every type of photovoltaic module and for all plant sizes. The product range covers both inverters for photovoltaic plants connected to the grid as well as inverters for off-grid systems. Since 2008, the Group’s parent company SMA Solar Technology AG has been listed on the Prime Standard of the Frankfurt Stock Exchange (S92) and also in the TecDAX index. In recent years, SMA has received numerous awards for its excellence as an employer.