Power Grid for a Naval Electric Ship - AC versus DC

The debate over the best electric grid topology for an all electric ship has provoked discussion on a wide range of topics, spanning interconnection issues, transmission losses, and power preferences of electronic components, radar ranges, and propulsion motors. Surprisingly, these issues are peripheral to the real issue. The primary driver in this debate is the power source, presently the gas turbine. The physics of the gas turbine demand the use of multiple turbines operating at different speeds. This demand assumes that system efficiency is the preeminent objective after functionality. The penalty for not using this approach is severe for fuel usage. A primal commitment to such a distribution of gas turbines serves as the basis for quantitatively comparing two ac systems and one dc distribution system. The power source combined with the navy’s focus on overall efficiency narrows the field of focus, and makes the rather complicated trade study tractable.