Relay Protection / IDMT Calculator (IEC 60255)
Explore inverse definite minimum time relay behavior using the selected curve and relay parameters.
What this utility does
The IDMT Relay Calculator evaluates an inverse-time relationship from the relay inputs supplied and presents a preliminary operating-time reference.
How to use
- Enter pickup, fault or multiple-of-pickup information, curve selection, and timing parameters.
- Review the calculated operating time.
- Compare the result with the relay manufacturer curve and the complete coordination study before applying a setting.
Practical notes
- Different relay families use different curve equations, constants, tolerances, and implementation details.
- A mathematical curve result does not by itself establish discrimination or selectivity in a real network.