A recent major upgrade to its La Rosière desalination plant, Jersey Water chose VLT® AQUA Drives from Danfoss. The principal reasons for choosing these dedicated water-industry drives were outstanding harmonic performance, high efficiency, compact construction and the availability of versions for operation from 690V supplies.
The current desalination plant is the second on the La Rosière site and opened in 1999 as a replacement for an earlier plant that had reached the end of its life. The growing need for water, due to population growth and climate change, led to a major upgrade. This would increase the plant’s capacity from 6 Ml/day to 10.8 Ml/day, which would meet around half of the island’s daily demand for water.
The upgrade involved the installation of many new pumps, with almost all needed to be controlled by AC variable speed drives. Jersey Water decided that the Danfoss VLT® AQUA Drives were the most suitable.
The largest of the new drives were required to control two high-pressure pumps with 600kW motors operating at 690V, which are fed from a custom 11kV/690V transformer. For these, 630kW VLT® AQUA Drives were chosen.
Other drives operate from 400V supplies and include three with 160kW ratings and nine with ratings between 55kW and 18.5kW. In addition, Danfoss supplied two 110kW VLT® MCD-series energy-saving soft start units for the seawater intake submersible pumps.
“Commissioning the new drives was fast and straightforward. The upgraded plant has been in service for many months, and the drives have fully lived up to expectations for performance and reliability. They are also making a big contribution to the enhanced energy efficiency of the plant, which has increased by between 36% and 38% since the upgrade” said Malcolm Berridge, Chief Engineer & Water Supply Manager for Jersey Water.
