A mathematical model proposal for maintenance strategies optimization of the most critical electrical equipment groups of hydroelectric power plants

WOS: 000483365300016Maintenance is a process that makes a high-level contribution to the sustainability goal of the manufacturing facilities defined as uninterrupted, high-quality level, economic, efficient; reliable and environmentally friendly production. The foremost stage of this important process is the maintenance planning and the first and indispensable phase of this stage is the maintenance strategy selection. When considering the maintenance processes which cause the significant costs due to production downtime, material, time and labor requirements, assignment of the suitable maintenance strategies especially for the critical equipment has great importance in terms of avoiding the unnecessary costs for the generation facility. Furthermore, maintenance strategy optimization directly effects the goal of sustainable production in the manufacturing facilities by providing to increase the faultless operating time of equipment and contribute to realize the reliable and high-quality manufacturing. In addition to these, this problem becomes more and more important in the electricity generation plants which are in the group of continuous production facilities, when the effects of energy on the society are considered. In this context in this study, among the electrical equipment which are the most problematic group, the most critical ones in terms of the power plant are determined by the AHP-TOPSIS combination in one of the big-scale hydroelectric power plants realize the 20% of Turkey's electricity generation. Then, the most appropriate strategy combination from corrective, periodic, predictive and revision maintenance strategies is obtained by using the proposed integer programming model for these equipment groups. The use of this combination has resulted in an 80% improvement in generation downtimes and associated costs

An Artificial Neural Network Model Supported With Multi Criteria Decision Making Approaches For Maintenance Planning In Hydroelectrıc Power Plants

DANISAN, TUGBA/0000-0003-1998-6810; Yumusak, Rabia/0000-0002-0257-939XWOS:000541497100003Power plants are the large-scale production facilities with the main purpose of realizing uninterrupted, reliable, efficient, economic and environmentally friendly energy generation. Maintenance is one of the critical factors in achieving these comprehensive goals, which are called as sustainable energy supply. The maintenance processes carried out in order to ensure sustainable energy supply in the power plants should be managed due to the costs arising from time requirement, the use of material and labor, and the loss of generation. In this respect, it is critical that the fault dates are forecasted, and maintenance is performed without failure in power plants consisting of thousands of equipment. In this context in this study, the maintenance planning problem for equipment with high criticality level is handled in one of the large-scale hydroelectric power plants that meet the quintile of Turkey's energy demand as of the end of 2018. In the first stage, the evaluation criteria determined by the power plant experts are weighted by the Analytical Hierarchy Process (AHP), which is an accepted method in the literature, in order to determine the criticality levels of the equipment in terms of power plant at the next stage. In order to obtain the final priority ranking of the equipment in terms of power plant within the scope of these weights, Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) is used because of its advantages compared to other outranking algorithms. As a result of this solution, for the 14 main equipment groups with the highest criticality level determined on the basis of the power plant, periods between two breakdowns are estimated, and maintenance planning is performed based on these periods. In the estimation phase, an artificial neural network (ANN) model has been established by using 11-years fault data for selected equipment groups and the probable fault dates are estimated by considering a production facility as a system without considering the sector for the first time in the literature. With the plan including the maintenance activities that will be carried out before the determined breakdown dates, increasing the generation efficiency, extending the economic life of the power plant, minimizing the generation costs, maximizing the plant availability rate and maximizing profit are aimed. The maintenance plan is implemented for 2 years in the power plant and the unit shutdowns resulting from the selected equipment groups are not met and the mentioned goals are reached.[2018/008]This study was conducted at Kirikkale University Projects Coordination Unit coded 2018/008 scientific research project

GOAL PROGRAMMING APPROACH FOR THE RADIOLOGY TECHNICIAN SCHEDULING PROBLEM

OZCAN, Evren Can/0000-0002-3662-6190WOS: 000505058700029Population growth is led to an increase in demand in the health sector. Health services need to be met at the maximum level in the face of increasing demand. The number of patients per each health personnel in Turkey is too much. Considering this situation, it is seen that ensuring patient satisfaction is directly proportional to the satisfaction of the personnel. For this reason, some studies such as the positioning of polyclinics and hospitals encountered in health services, capacity planning and demand estimations, as well as the studies about the creation of study schedules of health personnel are also gained importance. In this study, it is aimed to provide the personnel satisfaction as much as possible. The Law No. 3153 on Radiology, Radionomy and Electrical Therapy and Other Physiotherapy Institutions published by the Ministry of Health of the Republic of Turkey, dated 19/4/1937, as well as the requirements of the Annex-1 of 21/1/2010, is considered. The scheduling problem for eight radiology technicians working in a private hospital in Ankara is discussed. A mathematical model is proposed using the goal programming method in order to assign the technicians to the four shifts as equally as possible. According to the researches, this is the first study which has the feature of radiology technicians and by considering government and hospital conditions as well as with staff requests, by application area