Investigation of the Measurability of Selected Damage to Supporting Structures of Wind Turbines

Abstract

The present work deals with a measurability study of damage to supporting structures of wind turbines. The examined hybrid tower consists of a prestressed concrete part with an attached steel section on top. Principal focus is on developing a data preprocessing and analysis concept aiming to investigate the measurability of the two selected failure cases missing pretension of tendons and fatigue based change of Young’s modulus in reinforcement concrete. A simulation deduced out of real world mass and thrust forces provides a comparison with measured data based tower displacements, natural frequencies and mode shapes. The measurability of given deviations is investigated by means of virtual sensors, derived from the measurement setup of a test facility measuring acceleration, velocity, displacement and strain on different positions of the wind turbine tower, aiming the development of detection methods of such cases of damage for condition monitoring systems. The simulation input can be given by strain-based external forces or vibration-based displacements.

Operational Sensor Adjustment for Structural Health Monitoring Systems in Wind Turbines using Machine Learning

“…The sampling rate of 100 Hz is adequate to analyze the structure's Eigenmodes up to the 3 rd bending mode at 3.3 Hz as they are analyzed in [1]. To address data imbalance, such as for lower resolution SCADA data, missing values are filled by propagating from the last valid observation to the next valid observation or, for yaw angle data, using a fixed gradient backward interpolation method [9]. The dataset shows a predominant wind direction range between South-West and North-West, with negligible data share from North to East directions, although data from all wind directions is present, as illustrated in Figure 2.…”

“…[1] and [8] focus on the difficulties in capturing dynamic displacements and conducting frequency analysis, critical for turbine maintenance and RUL estimation. Similarly, [9] and [10] investigate the measurability of structural damages in wind turbines, focusing on dynamic and static displacement and frequency analysis challenges using advanced measurement and data preprocessing techniques.…”

Challenges to Overcome Obstacles in the Application of Structural Health Monitoring

“…They do include different types of sensors integrated in wind energy powerplants such as for monitoring ultrasonic guided waves and performing modal analysis (TU Clausthal jointly with DLR) [3], radar-based systems (Goethe Univ.) for monitoring the vibrational behavior of rotor blades [4] and the integrity of grouted joints [5], or loading on wind energy towers including monitoring of acceleration, temperature, strain, tilt, velocity or real time kinematics and feeding the data into digital models in the sense of a digital twin [6]. All of those demonstrators do provide data recorded from a variety of different sensors, that can be made available for further analysis as well as possibly merged in case circumstances allow.…”

Digital Twin Based Lightweighting of Robot Unmanned Ground Vehicles

“…Ryll et all [10] demonstrate the potential of the digital twin technology in a hybrid lightweight structure by realizing the demonstrator for creating a table size of aluminum profiles. Rupfle el all [11] used a digital twin for real-time analysis of load and displacement calculation of large-scale onshore wind turbines. Based on a digital twin data the "Message Queuing Telemetry Transport" (MQTT) transmission protocol was chosen for the lightweight design of constrained services.…”