OneLiner lets you plot the characteristics of distance relays in much the same way as overcurrent relays. OneLiner will also show the relay currents and operating times.
1. The relay group on the line between NEVADA 132 kV and REUSENS 132 kV should still be highlighted. Click on the relay group with the right mouse button.
A floating menu will appear.
2. Click on the View Relay Curves command in the floating menu.
A dialog box will appear asking you, which of the relays in the relay group you want to display.
3. Click on the 'DS phase relay NVPhase1' relay in the list box. Then, press OK.
The Distance Relay Window will appear showing the characteristics of the distance relay NVPhase1. The relay parameters will be shown inside a box to the right of the plot.
4. Select the Misc. | Options command.
A dialog box will appear.
These parameters include which units of time to display, which color to use for the circular grid and the desired font size.
Click on "Cancel" to accept the default settings.
The dialog box will close. We are now ready to show the relay operations for one of the faults.
5. Select the Show | Relay Operations for 1 Fault command.
A dialog box will appear asking you to select one of the fault solutions.
The close-in fault is already selected by default.
6. Press the Display button.
The dialog box will disappear and the window will be refreshed to look like the figure below. The fault description will be shown below the relay-parameter box.
The apparent impedances plotted on the complex plane are for informational purposes only.
OneLiner determines the operation of this KD relay from the XYZ-triangle principle. In general, each relay type is modeled using phase and magnitude comparators that are appropriate for that relay type. The tripping information (in text, within the parameter box) is the output of this detailed model. Details on distance relay modeling can be found in Section 2 of the Distance Relay User’s Manual (In the Main Window, click on Help | DS Relay Editor Help to see the on-line version).
In some cases – such as this one – the relay may trip even though none of the apparent impedances are within the relay characteristics.
7. Select the Misc | Close Window command.
The Distance Relay Window will close and we will be back to the Main Window of OneLiner.