Conference article

Recently; availability decrease due to increase of midnight electric power demand has risen necessities to improve economic efficiency of the pumped-storage power plants in South Korea. The necessities cause to extend a preventative maintenance cycle; especially an overhaul cycle. But; unconditional extension cannot be implemented because it may generate unanticipated failures due to insufficient maintenance. So; first; in this study; possibility of extension of the preventative maintenance cycle is identified via investigation on preventative maintenance situation of overseas and domestic hydropower plants. Second; a methodology to optimize the preventative maintenance cycle considering both reliability and economic efficiency is presented via review of the previous reliability studies and considering characteristics of the pumped-storage power plant. The methodology consists of the eight parts including selection of principal components and subcomponents; identification of damage mechanisms in the principal components/subcomponents; FMEA(failure mode effect analysis); derivation of replacement and repair time of the principal components/subcomponents; design of preventative maintenance cycle plan; reliability analysis; economic assessment; and derivation of the optimized preventative maintenance cycle. Also; as a result of application of the methodology to an aged pumped-storage power plant in South Korea; the overhaul cycle has been extended from 4 years to 7.5years. Last; effect of replacement of some aged principal subcomponents such as rotor runner and generator stator on economic profits is investigated via application of the methodology to the aged pumped-storage power plant.

Pumped-Storage Power Plants; Replacement; Preventative Maintenance; Reliability; Economic Efficiency