IEC 60076-4:2026 pdf download,Power transformers – Part 4: Lightning impulse and switching impulse tests of power transformers and reactors.
IEC 60076-4:2026 is a guide/standard in the IEC 60076 transformer series that details the methods for lightning impulse and switching impulse testing of power transformers and reactors. It explains how to perform these high-voltage impulse tests to verify that insulation and internal structures can withstand transient overvoltages that occur in electrical power systems. The document provides information on the required impulse waveforms, appropriate test circuits and test connections, earthing practices, failure detection methods, and the overall test procedures. It also covers measuring techniques and interpretation of results so that test outcomes can be evaluated consistently. Where relevant, it references recommended impulse test techniques from IEC 60060-1 and IEC 60060-2.