The fourth edition (2025) introduced significant updates to improve usability and accommodate ultra-high voltage (UHV) systems: IEC Webstore New Switching Impulse Definition : Standard switching impulse is now defined as 170/2500 µs , and the term "time-to-peak" has been replaced with " front time " to align with lightning impulse terminology. UHV Tolerance Updates

The you need (e.g., the 2010 version or the new 2025 revision)

These tests replicate slower transients created by opening or closing circuit breakers within the transmission network. Formally defined as a transient profile. Front Time ( T1cap T sub 1 ): Mandated at

i
Water
Admin
Streets
Country
Crop
Grass
Forest
Tundra
Sand
Swamp
Ice
Tiles
legend
legend

I--- Iec 60060-1 Pdf

The fourth edition (2025) introduced significant updates to improve usability and accommodate ultra-high voltage (UHV) systems: IEC Webstore New Switching Impulse Definition : Standard switching impulse is now defined as 170/2500 µs , and the term "time-to-peak" has been replaced with " front time " to align with lightning impulse terminology. UHV Tolerance Updates

The you need (e.g., the 2010 version or the new 2025 revision) i--- Iec 60060-1 Pdf

These tests replicate slower transients created by opening or closing circuit breakers within the transmission network. Formally defined as a transient profile. Front Time ( T1cap T sub 1 ): Mandated at The fourth edition (2025) introduced significant updates to