A Framework for Selection of Random Inspection Routes for Power Plants

Summary & ConclusionsThermoelectric and hydroelectric power plants are still the most important electric power generation systems worldwide, and the demand for such plants has considerably increased especially in several developing countries. Those plants have a complex monitoring system that intends to indicate degradation in the power plant operation, considering any abnormal degradation in their parts, which can be detected, by the monitoring system. Besides these monitoring systems, the power plants also have inspection routes executed by maintainers aiming at detecting early degradation in parts that do not have real time monitoring. During the inspection route, the maintainer is capable of evaluating the operational condition of pieces of equipment using portable measurement systems.The collected values are used to evaluate any abnormal operational condition and may be used to plan maintenance actions. For large power plants, there is a great number of parts that need to be inspected and it is almost impossible to have all of them inspected every day. So it is interesting to define a methodology to randomly select the pieces of equipment that will be inspected on each day, but using as a restriction that all pieces of equipment must be inspected in a given time interval.The present paper proposes a methodology to randomly select inspection routes used in power plants. The methodology is based on the application of FMEA to define the most critical pieces of equipment for the power plant. For those pieces of equipment, the inspection methodology must be selected considering their failure modes.Aiming at facilitating the maintainers’ tasks, the different pieces of equipment are grouped in sets such as heat exchangers, valves and others, according to the types of portable measurement instruments needed for inspection. For each group, a random process is used to select some pieces of equipment that will be inspected on a specific day. Therefore, every day some pieces of equipment are inspected, and after a specific period defined by the plant operator, the maintainers will have inspected all critical pieces of equipment.