ABB’s medium voltage PCS6000 converters have been awarded Underwriter Laboratories (UL) certification, the first in the US market to do so. This clears the way for their use in major US offshore wind projects that utilise the new generation of large-scale wind turbines, units that ABB believes could eventually reach ratings of 20 MW+.
The complex process of obtaining UL certification for the PCS6000 medium voltage WTG converters was initiated when ABB received an order for a major wind project in the US. Although the converters are already operating successfully in large markets worldwide, UL certification is mandatory for equipment delivered to the US market.
Medium voltage technology is used primarily in higher power wind turbines. But, until recently, most wind turbines in the US were based on low voltage technology. However, with the increasing power requirements for offshore turbines, the advantages of MV have become progressively more attractive, because LV systems can have difficulty coping with the higher currents and losses occurring in generators, converters and cables.
As a result, ABB initiated a programme of work with UL to determine which UL Standard would be most relevant. A decision was made to apply an existing safety Standard, UL 6141, for the certification process. Personnel from UL’s offices in Europe and headquarters in Northbrook, Illinois, worked with ABB staff at the company’s wind turbine converter engineering unit in Switzerland and the converter factory in Poland. The process included extensive component and design reviews, as well as type testing.
In addition to UL certification, the PCS6000 has product certification from the China General Certification Centre, CGC, and DNV-GL. It meets grid code requirements in the United States as well as major European countries, and several other countries worldwide.