Marine electrical installations

Abstract

The review gives a very brief history of the early days of the use of electric power at sea in commercial ships and then proceeds to the post-1960 period when marine systems changed from d.c. to a.c. Before system design is considered, the constraints imposed on designers are dealt with, such as the marine ambient conditions and the activites of regulatory bodies such as classification societies, statutory authorities and the Intergovernmental Maritime Consultative Organisation. Some recent statistical information is provided on d.c. and a.c. systems, choice of system frequency and voltage and relative sizes of installed generating capacity. System layout is described and the arguments in favour of earthed or insulated systems reviewed. Factors in the selection of generating plant are discussed and the need for voltage regulation and frequency regulation. This lead to the evaluation of system short-circuit currents and their inter-relationship with installed generating capacity and voltage regulation. Protection, installation of switchboards and cable construction are described. The problems associated with electrical installations in tankers (oil, gas and chemical) are outlined and some comparison made with tanker safety practices and safety practices employed in petrochemical plants ashore. Control and instumentation systems are then described. The history is briefly outlined leading to the present state where control arrangements are such that watchkeepers are withdrawn from the machinery spaces. System safety aspects and protective measures are described and operational experience to date outlined. A brief history of the modest use of computers at sea to date is included. This then leads to a forecast for future developments in marine control engineering. Finally, the review concludes by describing the equipment designed for use in the bridge area and the need for such equipment. Static electricity, electromagnetic compatibility and electric propulsion have not been dealt with in this review.