Siemens has developed a new air-insulated busbar trunking system that it says increases the efficiency and reliability of wind turbines. The LDM system from the Sivacon 8PS product family will replace cables for transmitting power from the generator to the grid in-feed. Siemens says that there will be construction cost gains, because the system is fast and cost-efficient to install, and exhibits increased efficiency in operation owing to reduced power losses. The low fire load achieved by avoiding the use of plastics, and standards-compliant design verification, increases the turbine’s operational safety. The system is designed for a rated current from 800 to 8200A.
The new busbar, a development of the existing LD system, is said to be maintenance-free and fail-safe. Optimised cross-sections enabled the efficiency to be significantly improved, which in turn decreases power loss. This means additional feed-in compensations for the plant operator throughout a wind turbine’s service life.
In contrast to using cables, the LDM system can be pre-installed in the individual tower segments during the construction phase. As the wind turbine is assembled, the individual busbar elements of the various segments are connected using a standard tool and only one bolt. The substantially wider fixing distances compared to cable installations speed up the installation of the new system and reduce the space and material needed. Owing to a special design feature, manufacturing tolerances can be compensated at the tower’s segment transitions; joint brackets with damper elements protect the system in case of tower movements.
The trunking meets the new IEC 61439-1/-6 standard, which requires design verification of the system. This ensures that the specified technical parameters are permanently fulfilled. Further parameters, such as the required short-circuit ratings, can be met by means of suitable dimensioning and engineering.
If necessary, the system can be connected directly to the switchboard at the base of the tower and via separate cable in-feeds to other equipment and to the loop cable. The system satisfies an IP21 degree of protection and is thus suitable for use in moisture- and salt-laden air.