Schweitzer Engineering Laboratories SEL-352-1 - Ground Overcurrent Element Test; Phase Overcurrent Element Tests

Date Code 20010731 Testing and Troubleshooting 11-13
SEL-352-1, -2 Instruction Manual
PHASE OVERCURRENT ELEMENT TESTS
Purpose: Verify the pickup thresholds of the 50LD, 50MD, and 50FT phase overcurrent
elements.
Method: 1. Using the TAR F command with the element name, set the bottom row of the
front-panel target LEDs to display the nondirectional instantaneous phase
overcurrent element. Select one of the phase overcurrent elements from the Relay
Word as indicated below: Many of the elements appear in the same Relay Word
row so they can be monitored simultaneously.
Setting
Elements
Fixed at 0.1 A (5 A)
or 0.02 A (1 A)
50MNA, 50MNB, 50MNC
50LD 50LD, 50LDA, 50LDB, 50LDC
50MD 50MD, 50MDA, 50MDB, 50MDC
50FT 50FT, 50FTA, 50FTB, 50FTC
2. Ramp current on the phase(s) under test and observe the pickup and dropout of
each element. Record the results.
3. Verify the test results with the appropriate setting. Use the SHO command to
check the setting.
GROUND OVERCURRENT ELEMENT TEST
Purpose: Verify the pickup threshold of the 50N ground overcurrent element.
Method: 1. Type TAR F 50N <ENTER> to set the fifth LED from the left of the bottom row
of the front-panel target LEDs to display the nondirectional instantaneous ground
overcurrent element.
Setting
Element
50N 50N
2. Ramp current on the phase under test, and observe the pickup and dropout of the
element. Record the results.
3. Verify the test results with the appropriate setting. Use the SHO command to
check the setting. The 50N element operates on 3I
0
. If current is applied to only
one phase, the pickup point should equal the setting.