An exercise to qualify LVAC and LVDC power system architectures for a Platform Supply Vessel

This paper attempts an investigation on low voltage AC (LVAC) and low voltage DC (LVDC) architectures with supply voltage of 690 V AC, 60 Hz and 1000 V DC respectively for a Platform Supply Vessel (PSV ). Quantitative evaluation of performance of both the architectures is exercised for a PSV based on fuel consumption (FC), weight, volume, gas emissions and reliability. The PSV has four identical Diesel Generators (DG) of 8000 kW total capacity. A methodology to assess the performance of each parameter is presented. The annual fuel consumption is assessed for equal load sharing among the DGs based on the PSV load profile. Accurate specific fuel consumption (SFC) -vs- load relationship is obtained from the brake specific fuel consumption (BSFC) chart of the diesel engines. The weight, volume and reliability are assessed based on the parameters of individual components like cables, circuit breakers, switchboards, DGs, propulsion motors and power converters. The emissions are assessed for NOx, SO2 and CO2 gases based on their emission factors. The proposed methodology can be applied with a reasonable confidence to make critical assessment of any power system architecture for marine vessel application.