Modeling and simulation of an LVDC shipboard power system: Voltage transients comparison with a standard LVAC solution

Voltage stability is a focal issue in every shipboard power system, where strict requirements (e.g. specified by STANAG 1008, classification rules, IEEE and IEC standards) are defined to guarantee safe operation under various operating conditions. This work proposes a low-voltage DC (LVDC) shipboard power system design and evaluates its voltage stability performance by comparing it with a standard low-voltage AC (LVAC) design. In order to evaluate the resulting transient performance, two different models are implemented with the aid of numerical simulation toolbox SimPowerSystems, working under the commercial software Matlab/Simulink. Voltage transients in LVAC and LVDC systems are simulated, resulting from an identical disturbance, i.e. disconnection of one of the Diesel Generators. From the observed transient responses, two different integral indices are used to assess the degree of system stability for both the LVAC and LVDC configurations. The indices considered are: Integral Absolute Error and Integral Time Absolute Error. The smaller values of the integral indices show the excellent capability of DC technology to maintain voltage stability following typical disturbances.