A process model was developed for the fabrication of closed shape composite structures such as thick-wall cylinders, with the emphasis on fiber bundle deformation and its effect on the process physics. A continuum mechanics model for fiber bundle deformation in the composite manufacturing processes was proposed. Based on this model, the winding and consolidation processes for thick wall cylindr...

frequency response analysis (fra) is popular technique which has been used since the last decade as a diagnostic method for transformers. however, accurate interpretation of fra measurements is still challenging. recent studies reveal that apart from winding deformation, fra data can also be influenced by moisture variation in transformer paper insulation. hence, a specific transformer’s model ...

Frequency Response Analysis (FRA) is popular technique which has been used since the last decade as a diagnostic method for transformers. However, accurate interpretation of FRA measurements is still challenging. Recent studies reveal that apart from winding deformation, FRA data can also be influenced by moisture variation in transformer paper insulation. Hence, a specific transformer’s model ...

The success of health monitoring and condition assessment of power transformers based on winding current signature analysis lies on proper extraction of features. The extraction of features in turn depends on appropriate signal processing methods. Fourier based signal analysis provides only frequency information and also suitable only for stationary signals. In this paper we present a combined ...

The development of transformer models can be achieved based on experimental frequency response measurements providing access to the windings is available and the physical dimensions are known in order to calculate R, L and C parameter values. Of interest are methods that allow the generation of a suitable model if the R, L and C parameters are unknown and access is restricted to the external te...

Improvement of diagnostic methods for both power and distribution transformers is crucial considering the part they play in electrical networks as well as their cost. Transfer function based testing of transformers is one of the methods that has been introduced recently. This method enables the identification of winding deformations resulting from the short circuit currents and winding dislocat...

Certain level of mechanical deformations in winding does not hamper the normal performance of power transformer. However, such incipient deformations if unattended could result in permanent failure of transformer. To this end, an approach is proposed to assess the severity of mechanical deformations in transformer winding. These deformations get reflected as changes in its high frequency behavi...

Modal parameters of power transformer winding are closely related to transformer manufacturing and detection technology of winding deformation based on vibration analysis method. Aimed at identifying the modal parameters of transformer winding accurately, a modal experiment is designed and made on a real 10 kV power transformer. An improved Empirical Mode Decomposition (EMD) algorithm is propos...