Outside, the test circuit was primed. In a real power grid, a short circuit is a disaster—a fallen tree or a lightning strike that bypasses the load. Under IEC 60076-5, Unit 42 had to prove it could survive several of these "faults" without its copper windings warping or its internal supports snapping. The Strike
For the purpose of short-circuit testing and design, transformers are divided into three categories based on their rated power: iTeh Standards Category I: Up to 2,500 kVA. Category II: 2,501 kVA to 100,000 kVA. Category III: Above 100,000 kVA. Methods of Demonstration iec 60076-5
For multi-winding transformers, the standard defines specific equivalent circuits for calculating short-circuit currents in each winding pair. Outside, the test circuit was primed