Fault Current
The extremely high current during a short circuit that transformers must withstand mechanically.
Fault current flows when a low-impedance fault occurs between phases or to ground. Can reach tens/hundreds of times rated current.
Transformers must withstand mechanical forces and thermal stress. Forces proportional to current squared—a 20x fault produces 400x normal forces. Impedance (4-15%) limits fault magnitude.
Withstand verified per IEC 60076-5 or by testing. Must survive bolted 3-phase short circuit for 2+ seconds.
QDTB designs with robust bracing, conductor support, and verified withstand capability. Our X/R ratio analysis ensures protection coordination.
Related Products
Related Terms
Impedance (%Z)
Total opposition to current flow in a transformer as a percentage, determining fault current and voltage regulation.
Short-Circuit Impedance (%Zsc)
Transformer impedance measured with one winding short-circuited, determining fault current and regulation.
Busbar
A metallic strip conducting electricity within switchgear, transformers, and distribution equipment.
Winding
Coils of insulated conductors in a transformer carrying current and linking magnetic flux for energy transfer.
More Terms Starting with “F”
Faraday Shield
An electrostatic shield between transformer windings blocking capacitive coupling of high-frequency noise.
Frequency (Hz)
The number of AC cycles per second (50 or 60 Hz), determining transformer design parameters.
Furan Analysis
A diagnostic measuring furan compounds in transformer oil to assess cellulose insulation degradation.
More in “Performance Parameters”
Core Loss
Power dissipated in the transformer magnetic core due to hysteresis and eddy currents, also called iron loss or no-load loss.
Copper Loss
Power lost as heat in transformer windings due to electrical resistance, proportional to the square of load current.
Efficiency Class (IE1-IE4)
International classification for transformer energy efficiency, IE1 (standard) to IE4 (premium) with progressively lower losses.
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