Comparison of voltage harmonics in AC and DC shipboard electrical power distribution systems: A case study of 17,500 DWT tanker vessel

Recently, direct current (DC) shipboard electrical power distribution systems has begun to be looked at to replace conventional alternating current (AC) distribution systems. DC distribution systems has some technical advantages such as lower power losses and drop voltage across the distribution cables. However, there is a drawback in its high harmonics distortion due to the utilization of AC-DC rectifier in the generation side and DC-AC inverter in the load side. This study tries to investigate how much increase of voltage harmonics when a conventional AC shipboard electrical power distribution systems is replaced with equal DC systems. A 17,500 deadweight tonnage (DWT) shipboard systems is used as the case study. Both of AC and DC distribution systems are modelled with a same generation and load systems in a simulation software and the results are being compared. The comparison shows that DC distribution systems generate voltage harmonics are higher than AC distribution systems for the sample vessel.