OPERATION SUMMARY - Section 3
3-22 MTS-3000 SERIES OPERATION AND REFERENCE MANUAL
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CU M004 01A
3.3.9 Differential Relay - Three Terminal Type
Most Electromechanical current differential relays are a three terminal type. This section describes how to
perform tests on this type of relay.
FIGURE 3.16 THREE TERMINAL DIFFERENTIAL RELAY TEST
3.3.9.1 PICKUP TEST.
Connect the relay as shown above. Connections are also shown for DC voltage supply to the relay if it
requires auxiliary power.
1.
Select slope display mode by entering the following key sequence: MENU | Settings | Display Optns |
Slope | 3wdg BDD style, followed by MENU again.
Selecting slope display mode forces the CM to display the % slope, operate current, and restraint current
on the 2nd and 3rd line of the CM. The phase angle of Ib also will change to 180
°.
2.
Disable the outputs if necessary by pressing ENABLE until its LED is out, and press FAULT. Its LED
will come on.
3.
Select the A phase of the current output module by pressing the F1 key on the module. Its LED will
come on and a cursor will flash slowly beneath the ‘A’ representing Amps in the F1 line of the
module’s display.
4.
Enter the desired restraint current via the MODIFY keyboard or rotary knob.
5.
Select the B phase of the current output module by pressing the F2 key on the module, and enter the
desired restraint current via the MODIFY keyboard or rotary knob.
6.
Enable the outputs by pressing ENABLE. Press and hold FAULT.