Comparison of fatigue loading in Francis turbine runners using extreme values interpolation

Abstract Extreme values of strain signals are important for hydroelectric turbine runners fatigue assessment. However, due to measurements limitations such as short data length and limited subset measured operation conditions, the extreme rarely fully captured. Our study aims estimate runner at non-measured operating conditions by interpolating components from ones. The method is based on peaks over threshold technique kriging interpolation. A case with two similar Francis turbines (same design power plant) presented. comparison made between use independent interpolation models a combined model turbines. This helps assess assumption that share loading. If case, common whole fleet in given facility could be considered, thus contribute reduce uncertainties related unmeasured loadings without need in-situ every runner.