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UBC Theses and Dissertations

Modeling forced outage in hydropower generating units for operations planning model Agrawal, Abhishek


Unplanned outages of generating units, also known as forced outages, act as a source of operational uncertainty for hydropower companies like BC Hydro. Forced outages reduce plant availability and causes loss of system flexibility and revenues. A combination of both likelihood of occurrence (frequency) and severity of outage event (duration) truly represents the risks posed by forced outages. Energy studies, using simulation and optimization models, are carried out by utility companies to incorporate different sources of uncertainties and maximize benefits in multi-purpose, multi-reservoir systems. The Department of System Optimization at BC Hydro is developing new quantitative approaches to model uncertainty of forced outages in their operations planning models and system energy studies. In this thesis, statistical properties of forced outage datasets are quantified, and different algorithms to generate scenarios of forced outages are developed. The statistical analysis methods and scenario generation algorithms are applied for a major hydroelectric facility in the BC Hydro system having 10 generating units and results are presented. Time to Failure and Time to Repair for outage events were obtained and checked for annual trends, seasonality and correlations. Outages of units were also evaluated for homogeneity. The impacts of planned outage on forced outages were quantified and suitable probabilistic distributions were developed to represent frequency and duration of outages. Three different scenario generation algorithms were developed using Markov/Semi-Markov based processes and Monte Carlo Simulation. It was found that Semi-Markov based scenario generation algorithm that comprehensively accounts for impacts of planned outages on forced outages is best suited to generate scenarios of forced outages for energy studies and operational planning models.

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Attribution-NonCommercial-NoDerivatives 4.0 International