MPx Ferry

We were contacted by the operator of Ro-Ro ferries who were experiencing a high number of unexplained equipment failures and system blackouts across a number of vessels in their fleet.

Power Quality surveys were carried out on 6 ferries with a number of consistent issues being identified: extremely high and non-compliant levels of harmonic distortion and high (damaging) levels of reactive power.

In all but one of the vessels surveyed, engine grounding was absent, giving rise to circulating currents within the systems installed. The provision of grounding to a common low potential earth bonding point provided a single path for the ac currents previously assumed to have been circulating within the engine, generator and bearing units.

We also noted that the lack of effective isolation between the ac and dc systems and the star connection point on the transformers was a major factor in the poor power quality measured.

We found a high predominance of 3rd order and 5th order harmonics and high (to very high) reactive power contribution resulting in a low power.

Discussions with ferry owner regarding improvements to the generation and distribution systems are ongoing.