Effect of load changes on hybrid electric ship power systems

Load transients are often the cause of power failures leading to blackouts or malfunction of sensitive equipment on-board electric ships. Having number of operating modes, hybrid electric ships face the same issue at a higher probability. This paper focuses on assessing the effects of load changes on hybrid electric ship power systems at different operating modes. Hybrid electric propulsion and the different modes of operation are first described in detail. Subsequently, the modelling of the hybrid shipboard power system using the MATLAB/Simulink platform is done. Load-changes are applied to this system in order to investigate the transient effects particularly focusing on the system voltage and frequency caused by varying the magnitudes and types of loads that occur in the different modes of a hybrid ship's operation. This study has attempted to find the nature of the load as well as the hybrid ship operating modes that have a greater effect on the voltage and frequency transient conditions resulting from load variations. These findings help determine the suitable operating mode of a hybrid ship in the different loading scenarios at sea so as to minimise the voltage and frequency fluctuations encountered during the transient period.