Mechanical Behaviour of the Cellulosic Dielectric Materials of Windings in Power Transformers in Operation

Oria, C.; Ortiz, Alfredo; Fernández, Inmaculada; Carrascal, I.; Ferreño, Diego

doi:10.1109/icelmach.2018.8506963

Cited by 1 publication

(1 citation statement)

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“…For the sake of simplicity, both the curvature and the transposition in the CTC were ignored in the model, as in [4]. Previously in [16], a solid rectangular crosssection was modelled, and the final deflection numerically obtained was significantly lower than the experimental one, which confirms the need for the inclusion of the individual strands and the sliding between them, Figure 15b. An approximate symmetrical cross section was modelled in SpaceClaim, composed of 18 rectangular strands (nine in each stack) of 11 x 1.9 mm with rounded corners, Figure 15c.…”

Section: Geometry Supports and Materialsmentioning

confidence: 77%

Experimental and numerical analysis of cellulosic insulation failures of continuously transposed conductors under short circuits and thermal ageing in power transformers

Oria

Carrascal

Ortiz

et al. 2020

IEEE Trans. Dielect. Electr. Insul.

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The integrity of the cellulosic insulation in power transformers is considered one of the most relevant parameters that affects their performance and reliability. Electric faults, such as short circuits, have thermal and mechanical effects that degrade the paper and can eventually produce the end-of-life of the transformer. The evolution of the properties of the paper insulation of a commercial continuously transposed conductor due to thermal ageing was characterised through the degree of polymerisation and tensile testing. Failure initiation and propagation in the paper was analysed macroscopically and microscopically using scanning electron microscope. A finite element numerical mechanical model of the conductor was implemented to reproduce the experiments and to obtain the load level and strain state that produce failure at each ageing state, aiming at developing a failure model for the insulation. This model may contribute to an improvement in manufacturing processes and management of the electrical system.

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Section: Geometry Supports and Materialsmentioning

confidence: 77%