An Assessment of Steady State, Transient and Fault Conditions Within a Concept Ship Submersible Conventional Power System
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This thesis reports on research performed on the modelling and simulation of a full concept design Ship Submersible Conventional electrical power and propulsion system. In order to achieve this the research programme undertook a review of three sets of pertinent Classification Society design codes (Rules) and a design review of two historic submarine classes. Based on the outcome of the Rule review a concept 55 m submarine design was produced in order to support the design of a full concept power and propulsion system. Dynamic models of each of the power and propulsion system’s electrical machines and sub-systems were then successfully developed. The individual electrical machine and sub-system models were then integrated to form an holistic power and propulsion system model that was used to successfully demonstrate equipment mutual compatibility and power / propulsion system stability. The model was then used to establish the impact of: (a) alternate proportional, integral control strategies – this work established that strategies with a reduced integral gain setting provide viable alternates to the widely used Ziegler & Nichols (1942) settings when a system exhibits unacceptable or excessive sensitivity and (b) the impact of pulsed battery charging – this work established that pulse charging cannot be simply introduced into an extant power system without incurring severe stability consequences. The research programme finally investigated a Millman (1940) based alternate to symmetric components for calculating unbalanced fault currents in three phase power systems. This work confirmed that the Millman (1940) based approach produces results that are broadly comparable to symmetric component methods without recourse to fictitious sequence networks or components, making it a conceptually simpler approach.