Power quality on ships-a questionnaire evaluation concerning island power system

Limited knowledge exists on power quality aspects and requirements of ships in the same extent as similar applications for offshore and island power systems. An important reason for power quality studies on ships is accidents or incidences. One example is an accident in the archipelago of Stockholm, when a ferry stroked the ground, and large voltage harmonics were measured. Another example is manoeuvring in harbours with a cargo ship, which could not use its cargo lifts and besides have problems with some of the electronic equipment at the bridge. In this case no investigation has been done, but voltage dips are suspected. To get a picture of the situation, a questionnaire has been send to ship owners in Sweden and Aland (Finland). The result of this questionnaire is presented here in addition to a study of statistic data from the "Swedish Maritime Administration" containing sea accidents.