Maintenance Schedule Optimization Applied to Large Hydroelectric Plants: Towards a Methodology Encompassing Regulatory Aspects

The maintenance schedule planning of hydro plant generating units is a subject of great interest to several agents in the energy industry. A correct approach for this problem can prevent the degradation of physical assets and minimize the probability of forced shutdowns of their equipment. In addition to these factors, due particularities of the Brazilian system, the operational strategies of its agents are also affected by the maintenance schedule of the generating units. This occurs due to the Availability Factor (AFA), which is directly influenced by the hours of maintenance performed at the plant and, in case of a performance below the stipulated in the concession contracts, it can lead to financial losses or administrative sanctions applied by the regulatory agent. With this motivation in mind, the present work proposes a methodology for Generator Maintenance Scheduling (GMS) of a hydroelectric plant, developing a mathematical model to determine the ideal moment to perform maintenance, considering operational restrictions and regulatory aspects of hydroelectric plants. The optimization methodology proposed for this problem is done through mixed-integer linear programming, where the integer variables consist of the operating state and start date of maintenance of each generating unit. In the end, to validate the proposed modeling, a case study is carried out for a real large plant in the Brazilian system.