A Combinatorial Safety Analysis of Cruise Ship Diesel–Electric Propulsion Plant Blackout

Victor Bolbot,Rainer Hamann,Gerasimos Theotokatos,Evangelos Boulougouris,George Psarros

doi:10.3390/safety7020038

Victor Bolbot, Rainer Hamann + Show 3 more

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https://doi.org/10.3390/safety7020038

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Abstract

Diesel–Electric Propulsion (DEP) has been widely used for the propulsion of various ship types including cruise ships. Considering the potential consequences of blackouts, especially on cruise ships, it is essential to design and operate the ships’ power plants for avoiding and preventing such events. This study aims at implementing a comprehensive safety analysis for a cruise ship Diesel–Electric Propulsion (DEP) plant focusing on blackout events. The Combinatorial Approach to Safety Analysis (CASA) method is used to develop Fault Trees considering the blackout as the top event, and subsequently estimate the blackout frequency as well as implement importance analysis. The derived results demonstrate that the overall blackout frequency is close to corresponding values reported in the pertinent literature as well as estimations based on available accident investigations. This study deduces that the blackout frequency depends on the number of operating Diesel Generator (DG) sets, the DG set’s loading profile, the amount of electrical load that can be tripped during overload conditions and the plant operation phase. In addition, failures of the engine auxiliary systems and the fast-electrical load reduction functions, as well as the power generation control components, are identified as important. This study demonstrates the applicability of the CASA method to complex marine systems and reveals the parameters influencing the investigated system blackout frequency, thus providing better insights for these systems’ safety analysis and enhancement.

Highlights

The ship propulsion and electric power generating functions of modern cruise ships are realised using the Diesel-Electric Propulsion (DEP) plants [1,2,3]
Each sub hazard/hazard is used an initiating event and the propagation of sub hazards into other hazards or sub hazards is as an initiating event and the propagation of sub hazards into other hazards or sub hazexamined by considering the interactions between the system components, the presence of ards is examined by considering the interactions between the system components, the protective barriers and the combinatory faults using Event Sequence Identification (ESI)
The operating Diesel Generator (DG) set overload leading to a blackout event is represented in this FT to show the relationship between Fault Trees shown in Figures 7 and 8

Summary

Introduction

The ship propulsion and electric power generating functions of modern cruise ships are realised using the Diesel-Electric Propulsion (DEP) plants [1,2,3] In such cases, loss of electric power (blackout) during the ship sailing or manoeuvring may result in a number of accidents such as collision, contact and grounding, which, in turn, may cause considerable human losses of passengers and crew [4] associated with severe environmental and reputational loss consequences. FTA and FMEA [18], the HiP-HOPS method [19,20], System-Theoretic Process Analysis (STPA) [21,22,23,24], combinatory methods [25], accident investigation data [26], reachability analysis [27], and Markov[25], chains [28]. Other studies for ensuring the safety of cruise ship power plants involved dynamic simulations [7,8], Reliability Block Diagrams [9,10,11], FMEA [12,13,14], Fault Tree Analysis (FTA) [15,16,17], FTA and FMEA [18], the HiP-HOPS method [19,20], System-Theoretic Process Analysis (STPA) [21,22,23,24], 4.0/).

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