I have modfied and improved the T/C curve presented in Time-Current Curve Part 2 - Discrimination. The changes are:

  1. Each curve can now be set to any curve type
    • Standard Inverse
    • Very Inverse
    • Extremely Inverse
    • Long Time Inverse
  2. Added earth fault curve - Definite Time (DT). Settings are
    • Earth Fault Setting as a factor of In (xIn)
    • Earth Fault High Setting as a factor of In (xIn)
    • Earth Fault Time Setting

A typical curve is shown below:

Please take time to read the Disclaimer before downloading.

Download:Time-current-curves V2


  • A Filipino Engineer, Registered Professional Engineer of Queensland (RPEQ) - Australia, and Professional Electrical Engineer (PEE 2574 - 1st Place April 1991) - Philippines with extensive experience in concept selection, front-end engineering, HV & LV detail design, construction, and commissioning of Hazardous and Non-Hazardous Area electrical installations in water and wastewater pipeline and pumping facilities, offshore platforms, hydrocarbon process plants and pipelines including related facilities. Hazardous area classification and design certification (UEENEEM015B, UEENEEM016B, UEENEEM017B).