Semiparametric statistical analysis of the blade tip timing data for detection of turbine rotor speed instabilities

Abstract

In this paper, we propose an extension of an existing standard approach to the blade tip timing data when analyzing turbine rotor vibrations. Instabilities related to the non‐constant trigonometric coefficients at prominent frequencies might not be noticed in the traditional analyses. Our methodology is based on time‐varying coefficient statistical models, and hence it allows a full formalization of the estimation and other inferential tasks (uncertainty assessments, hypothesis tests etc.). First, we formulate a univariate generalized additive model that is useful for investigation of vibration behavior of individual blades. It can extract trajectories of the trigonometric coefficients. Using the trajectories, one can investigate time changes of power at a given frequency. In the second approach, we use a multivariate model for simultaneous assessment of all of the rotor blades. The model acknowledges similarity of the vibration behavior of closely located blades. It is formulated as a state‐space model, and hence it allows for a wide range of prediction, smoothing, and filtering tasks. We illustrate the performance and practical usefulness of our models on real blade tip timing turbine monitoring data obtained from the Czech nuclear power plant Temelin.

A fatigue reliability assessment approach for wind turbine blades based on continuous time Bayesian network and FEA

“…It is due to the fact that, as primary load‐bearing structure, shear web fails faster compared with other components for its complicated force situation, which makes its failure has the greatest impact on the system. Though the blade root withstands a greater stress, some reinforcement measures are often applied in the stages of design and manufacturing, thus the safety and reliability are improved 39,40 . Leading edge and trailing edge are the bonding areas of the upper and lower shells, and their failures are mainly caused by environmental factors, such as rain erosion, salt spray, etc., but not only the alternating cycle stresses 41,42 .…”

“…Though the blade root withstands a greater stress, some reinforcement measures are often applied in the stages of design and manufacturing, thus the safety and reliability are improved. 39,40 Leading edge and trailing edge are the bonding areas of the upper and lower shells, and their failures are mainly caused by environmental factors, such as rain erosion, salt spray, etc., but not only the alternating cycle stresses. 41,42 Thus the local fatigue failure in leading edge or trailing edge, combined with the environmental factors impact analysis, requires more in-depth study.…”

The ENBIS‐17 Quality and Reliability Engineering International Special Issue

“…The paper by Marek Brabec, Pavel Prochazka, and Dusan Maturkanic proposes an extension of an existing standard approach to the blade tip timing data when analyzing turbine rotor vibrations . The methodology is based on time‐varying coefficient statistical models allowing a full formalization of the estimation and other inferential tasks.…”