Select the System tab of the Options dialog box to set system parameters.
Figure 1: System Tab of Options Dialog Box
Base MVA: The base MVA of the system your one-line represents.
Frequency: The frequency of the system your one-line represents. This number is used for some of the database dialog box Calculate buttons. Make sure it is correct before you build your one-line.
The above fields are active in the Database Edit focus only.
Units: Select U.S. or Metric, depending on your application.
Symbols: Select either ANSI or IEC to change the one-line symbols used to represent different items (such as transformers) in the power system you are modeling.
SC Calculation Method: Based on the short circuit calculation features you have purchased, you can select ANSI or IEC short circuit method.
Note: The SC Calculation Method must be set to ANSI to run the Arc Flash Scenario Comparison Report. Both ANSI and IEC are supported for the Equipment Duty Scenario Comparison Report.
Generator 30 Cycle X: The 30 cycle reactance for generator can be selected as 1.5x momentary reactance (1.5*MomX, the default), or the transient reactance (X’dv).
Arc Flash Ground Vpu: In arc flash hazard calculations, the program determines that a bus is effectively grounded if the average voltage per unit for B and C phases during a line-to-ground fault on A phase is less than the value specified in this field.
The C factors, also known as voltage factors, are defined by IEC 60909 in table I for Low, Medium and High voltages respectively. Different per-unit multiples of the voltages are used for the calculation of maximum short circuit currents and minimum short circuit currents.
Show stability symbols in database focus: Equipment such as motors and generators with stability data have different symbols in the Dynamic Stability focus. These symbols can be made to appear in the Database Edit focus also with this check box selected.
Use 100% convention for displaying analysis overloads/overduties: Displays the calculated duty or loading of equipment as a percentage of the rating. For example, if a cable has a rating of 100A and the load current is 95A, then the cable overloading is displayed on the one-line as 95%. Without this option enabled, the display is -5%.
| Customizing EasyPower | |
| Setting the Short Circuit Method |