Comparative analysis of the hydropower plant transient processes for various surge tank types and improved guide vanes closing law

Abstract

Analysis of transient processes is necessary at the design stage as well as during refurbishment of a hydropower plant (HPP). Comprehensive analysis of non-stationary phenomena during transient processes at HPP implies investigation on possible improvements through operation and constructive protection measures. In this paper, the analysis of relevant constructive measures for HPP Pirot is presented comprising the improved tri-linear guide vanes closing law, which can be implemented instead of the current linear one. HPP Pirot is equipped with the two-chamber surge tank and synchronous pressure regulating valves (SPRVs) on the turbines. SPRVs are installed directly at turbines spiral cases, and their opening law is complementary to the closing law of the guide vanes. Prior to analyzing the HPP characteristics during emergency shut down regime for various potential surge tank types, the research of the safety of the existing surge tank with the improved closing law has been conducted for the same operational condition.