Run a Power Flow Analysis

Open the Power Flow Focus

Open the Power Flow focus by clicking Power Flow. If one or more items are unconnected or have incomplete data, you will be notified at this time. Items with incomplete data are highlighted in red. An error message dialog box appears. To see the errors, click View Report. An error report appears as shown below, listing the equipment with incomplete data.

A message box is displayed indicating that equipment with incomplete date were found. There are options to View Report or Cancel.

Figure 1: Error Message – Incomplete Data

The error report is displayed indicating there is missing information on the cable and utility.

Figure 2: Error Report – Incomplete Data

Double-click on the item in the one-line to open the item's data dialog box, and enter any missing data. Then open the Power Flow focus again.

Solve Base Case Power Flow

Click Solve to see all the flows.

The one-line diagram is shown with many of the equipment items highlighted in red, showing power flow results. Some of the text overlaps.

Figure 3: Solved Flow Example

You can see that we underestimated the amount of space to leave for analysis the results. EasyPower's dynamic graphics make this easy to fix.

Adjusting One-line for Results Readability

Drag the buses, equipment, and ID names as needed to see so all of the analysis numbers.

After adjusting the one-line, you can save the updated arrangement with the Save command even though you are still in the Power Flow focus.

The one-line items have been adjusted so the text no longer overlaps.

Figure 4: Better Readability in One-line

Interpreting the Results

The power flow solution is initially displayed in megawatts and megavars. You can change this to kilowatts and kilovars if desired by clicking PF Options > One-line Output on the Power Flow tab. Flow direction is indicated by the arrow. MVAR flow is indicated by the value placed in parenthesis ( ). The numbers beneath the motors show the actual loading of each motor.

Voltage is shown on the right-hand side of each bus at a forty-five degree angle. The default voltage unit is per-unit, but kV can be shown instead if desired. The number after the "@" is the voltage angle (excluding 30° phase shift) in degrees. This is the voltage angle in comparison to the voltage angle at the swing bus (usually 0°).

Notice that the flow into each branch is different than the flow out of each branch. This is due to the line losses associated with each conductor and transformer.

There are many other power flow display commands available. You can use the buttons on the Power Flow tab to change which values and warning conditions are displayed.

If the Power Flow tab has Voltage Violation selected, most of the buses will be highlighted in red since their voltages are outside the warning threshold range as determined in Power Flow Options > Control.

If your results do not match these numbers, recheck the database dialog boxes for each item, comparing them to the dialog boxes shown in this tutorial. To do this, you must first get back to the Database Edit focus by clicking Database Edit.

Next: Run a Short Circuit Analysis

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