Assessment of current fatigue state of the wind power station tower by non-destructive method of measurement of the magnetic characteristic of metal – coercive force

Speaker:
Solomakha, R.N.; CM Diagnostics; Ukraine

Authors:
Bezlyudko, G.; Special Scientific Engineering; Ukraine
Lukina, A.; Special Scientific Engineering; Ukraine
Morgner, W.; Special Scientific Engineering; Ukraine
Savluk, S V.; Special Scientific Engineering; Ukraine
Shnittger, C.; Special Scientific Engineering; Ukraine
Solomakha, R.N.; CM Diagnostics; Ukraine

ID: ECNDT-0072-2018
Session: Energy Generation
Room: G3
Date: 2018-06-12
Time: 16:40 - 17:00

The results of inspection of current state of all-metal welded tower of wind power station are presented. Height ∼ 100 m, current term of exploitation – 12 years. Inspection of current fatigue and stress state was conducted by non-destructive method of measurement of the magnetic characteristic of metal – coercive force.
Fatigue degradation of metal depending on height for welded joints metal, heat-affected zones metal, and tower main body metal, metal of flanges which connect all 4 sections of the tower into integral high-rise construction is presented. The weakest zone of the tower in the top-most section No IV was defined by coercimetry. Coercive force of metal increased ∼ 2.5 times comparing to initial state. Residual lifetime forecast for this zone amounts ∼ 16 years. Magnetometrical assessment of fatigue state of flange bolts was conducted by non-destructive method of measurement of magnetic field induction of magnetization of each bolt in natural Earth’s magnetic field.
Results of coercimetry for tower demonstrate the weakest zone of the construction and provide a means of grounded increase of axial rigidity of tower just as for current construction and its production technology so too amendment of the construction. Coercimetry provide a means of detection of wind power plant with the highest fatigue level and the weakest zone of the detected wind power plant. This opens a possibility to perform preventive repairing or decrease loading regime for avoidance of destruction. In accident investigation coercimetry declares if metal fatigue is a cause of the accident or not. It seems that extension of wind power plant service life upon expiring of its passport service life without assess of main components fatigue could not be objective. These days such assess can be conducted as a practical inspection by coercimetry only.