Study Of Modern Marine Electrical Equipment Maintenance Decision-making Method

The operation reliability of the power transformer, the key equipment in electrical power system of modern vessel, is closely related to the safety and stability of electrical power system. With the automatic of the vessel becomes higher and higher, the influence of accidents caused by electrical power system is greater and greater. For a long time, the test, check and maintenance to electrical equipments are carried out in time-based manner during power cut. This kind of maintenance mechanism has played a very important role in guaranteeing safety of electric equipment operation. With the widely accepted technology of Condition-Based Maintenance, Condition-Based Maintenance technology replaces Time-Based Maintenance will be the inevitable developing trend.The basic flow chart of Condition-Based Maintenance to electric equipment is: Firstly, to assess the health state of electric equipment under operation using data obtained through timed preventive test or on-line monitoring, and the history recordings of the electric equipment. Secondly, to give some judgments in terms of rules of Condition-Based Maintenance, to put forward some maintenance scenarios in term of actual situation. Finally, to select the optimal scenario from limited scenarios using technical and economical comparison. In the process, it involves many assessment targets and many decision makers. Based on a lot of relevant references, the paper mainly researches on the following contents:The rationale and method of adopting grey clustering decision-making to health state of electric equipment are presented. Firstly, the states of electric equipment are divided into five grey classes, then the whitenization weight function of the five grey classes are established, the state information involved in assessing the state of electric equipment are analyzed, and finally the steps of grey clustering decision-making to the state of electric equipment are presented.The decision-making of Condition-Based Maintenance to electric equipment involves many assessment targets in decision-making and the judgments to these targets are made by domain experts and engineers. The judgment cannot be measured by a strict standard but a fuzzy concept. So the author introduces the method of fuzzy decision-making to Condition-Based Maintenance decision-making of electric equipment, puts forward to adopt the method of fuzzy multiple attribute decision-making to analyze the Condition-Based Maintenance decision-making of electric equipment, also researches the decision-making targets and maintenance scenarios. By analysis actual example, the paper assesses the maintenance scenarios using fuzzy simple weighted mean method and fuzzy multiple attribute compromised decision-making respectively, and the consequence is conformable.Because the assessment of Condition-Based Maintenance scenarios to electric equipment involves not only many assessment targets, but also many decision makers, such as, managers of the vessel electrical power system, technical departments of ship company, leaders of ship company, and so on. The importance of the targets considered bydecision makers, the bias of decision makers and the authoritativeness of decision makers are different, the judgment given by different kinds of decision makers are still the fuzzy concept. So the author puts forward to adopt the fuzzy multiple attribute and many experts group decision-making method to assess the Condition-Based Maintenance scenarios of electric equipment. The decision-making targets, makers and the weight of authoritativeness of decision makers are discussed and the steps of algorithm are presented. By analysis actual example, the paper assesses the maintenance scenarios using fuzzy simple weighted mean group decision-making method and fuzzy multiple attribute compromised group decision-making respectively, and the consequence is conformable.In a word, all kinds of methods of decision-making presented in the paper not only have important academic values but also have proper leading significance in practice.