Investigation of interaction between pressure relief valve and turbines during a transient flow in hydropower plant

Çetintaş, Mehmet Ali
The main goal of the present study is to investigate the effect of pressure relief valve (PRV) on the hydraulic transients generated by multiple turbine operations. To achieve this goal, a numerical model of KEPEZ-I Hydropower plant is constructed in the Bentley HAMMER software, which employs the Method of Characteristics (MoC) for computations. The MoC has been proven worldwide as a versatile and accurate tool for solving non-linear, hyperbolic, partial differential equations in space-time domain for hydraulic transients. The available field data for some specific turbine operations were used to calibrate the numerical model first. The simultaneously measured data from the field such as turbine closure and PRV opening adjustments, and pressure measurements were very useful in establishing and validating the numerical model in the software for the further analyses. Once the confidence was gained for the accuracy of the model a number of numerical simulations were performed for various turbine operations to understand the response of the plant to the transients. Since a pressure relief valve (PRV) is mounted in the hydropower plant already, the study mainly focuses on the effect of PRV on the transients generated by those turbine operations. Different scenarios such as instant load rejection, load acceptance, load variation are applied to the system with and without PRV. The operating conditions of the hydropower plant are analyzed, and the operation limits are determined to prevent any damage to the system by using the computer software. Potentially, most critical operational cases for the penstocks are selected, and the effects of the PRV are observed on the transient flow. It is found that PRV reduces approximately 50% of sudden pressure increase near the turbines. The power plant is protected against the adverse effects of water hammer transients as long as it is operated within the guidelines specified in the thesis.


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Citation Formats
M. A. Çetintaş, “Investigation of interaction between pressure relief valve and turbines during a transient flow in hydropower plant,” M.S. - Master of Science, Middle East Technical University, 2022.