Evaluating the Reliability and Availability of Kaligandaki "A" Hydropower Station (144MW) using a Markov-Based Approach

Abstract

The Kaligandaki "A" Hydropower Station plays a vital role in meeting the growing energy demands of Western Nepal. As hydropower stations are critical infrastructure assets, ensuring their reliability and availability is of utmost importance. This thesis presents a comprehensive evaluation of the reliability and availability of the Kaligandaki "A" Hydropower Station using a Markov model which is conducted by collecting the daily operational and maintenance data for the period of FY 2016/17 to FY 2022/23. The primary indicators of reliability indices such as failure rate (λ), repair rate (μ), MTTR, MTBF, and MTTF were obtained by collecting and analysing data. Operational data for each unit on an annual basis were obtained from the hydropower station. Once all the data had been organized, the different types of failures for each unit were categorized, considering the various sub-units and systems involved. Based on this classification, Markov states are established. The failure rate and repair rate for each state are determined using the categorized data. Finally, availability and reliability are calculated based on their respective definitions. The reliability scores of the units ranged from 0.952622 to 0.999762, while the availability scores ranged from 0.568571 to 0.894388. The data analysis conducted from fiscal year 2016/17 to fiscal year 2022/23 indicates that the station exhibits a high level of reliability, with a majority of instances exceeding 99%. Additionally, the station demonstrates a strong availability rate, surpassing 98% during the same period