What Are the Forces on a Transformer During a Short Circuit?
Quick answer — During a short circuit, the fault current produces large electromagnetic forces on the windings that scale with the square of the current. Radial forces push the outer winding outwards (tension) and the inner winding inwards (compression), while axial forces push the windings vertically when the ampere-turns are unbalanced. The design must size the conductors, spacers and clamping so these forces do not deform or collapse the windings.
What forces act on a transformer during a short circuit?
Radial forces
The leakage field interacts with the winding current to push the conductors radially: the outer winding is under tension, the inner under compression. Buckling or stretching is the risk.
Axial forces
If the ampere-turns of the HV and LV are not balanced, an axial force compresses or pushes the windings and their clamps. Clamping and end rings must resist this.
Design and testing
The designer sizes the conductor and the axial/radial support, and the transformer is proven by the short-circuit withstand test (IEC 60076-5) so it survives the worst-case fault.
Equation — F ∝ I² (force scales with the square of the fault current)
References & standards
- IEC 60076-5 (short-circuit)
- IEEE C57.12.90
Related
Related manufacturers
Prolec GE (GE Vernova) · Prolec GE Waukesha · Hitachi Energy USA · Siemens Energy · Eaton · Virginia Transformer Corp
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Technical content is prepared from engineering references, standards frameworks, manufacturer documentation and industry sources. Contractual or compliance decisions should refer to current official standards. TransformerPath Technical Editorial.
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