Changing the IEC Standard Time Interval
The following currents can be calculated in EasyPower:
- Initial current: This is the first cycle current. To display results for this current, click
Initial in the Short Circuit tab. - Breaking currents for 0.02 seconds, 0.05 seconds, 0.1 seconds and 0.25 seconds: To display these values, click the corresponding buttons in the Short Circuit tab.
- Steady State: To display the steady state current, click
Steady State in the Short Circuit tab. Steady state displays the current flow after 0.5 seconds. For three-phase faults, steady state currents are based on the meshed network equations in IEC 60909-0 (84) and (85), where motor contributions are not included in the calculations. For unbalanced faults, motor contributions are included if the C factor is set to Max in the Short Circuit Options. Otherwise, the motor contributions are not included.
You can view up to 3 types of fault current values by time interval.
Figure 1: Short Circuit Results at Various Time Intervals
You can also view fault currents in various forms, such as by phase current values (A, B, C) or their symmetrical component values (positive sequence, negative sequence, zero sequence or 3 times the zero sequence).
