This document describes a solution for provision of backup power for wind
turbines in offshore windfarms by the use of a Low Voltage Direct Current, LVDC,
power distribution system. The solution is based on a relatively small central
LVDC power supply such as a diesel generator placed on the offshore transformer
platform feeding power through LVDC cables to the individual wind turbines.
An advantage of using LVDC is that relatively large amounts of power can
be supplied over relatively long distances as compared to what is the case using
Low Voltage AC systems. The solution means less and smaller equipment on the
offshore platform, and less diesel fuel consumption.
Another advantage is
that the LVDC power distribution system does not involve the Medium Voltage
Alternating Current, MVAC, power collection system connecting the wind turbines,
and thereby does not need a relatively large diesel generator and/or a reaktive
power compensation system to allow for the MVAC array cable and inrush currens
when energising MVAC transformers.