Schweitzer Engineering SEL-387-0, Instruction Manual

Page: 395 / 556

10.15
Date Code 20170601 Instruction Manual SEL-387-0, -5, -6 Relay
Testing and Troubleshooting
Acceptance Testing
b. Enter SET 51P1TC <Enter> .
c. When prompted, set 51P1TC to IN101. Note that the
51P1TC can be set to 1 (always asserted) or 0 (always
deasserted) for testing instead of asserting an input.
Step 2. Purpose: Assert the torque-control equation.
Method: Apply the appropriate conditions to assert the torque-
control equation. For this test example, apply control voltage to
IN101.
Step 3. Purpose: Display the appropriate Relay Word bit to verify the
torque-control equation.
Method: Execute the TARGET command (i.e., T AR F IN101
<Enter>) . The SEL-387 now displays the state of the six input
elements in the second row of the front-panel LEDs. If multiple
elements are used in the torque-control equation, several
TARGET commands must be issued to view the individual
elements.
Step 4. Purpose: Display the appropriate Relay Word bit on the front-
panel LEDs for the desired overcurrent element.
Step 5. Method: Execute the TARGET command (i.e., TAR F 51P1
<Enter> ). The SEL-387 now displays the state of several
overcurrent elements in the second row of the front-panel
LEDs. The 51P1 bit is the fourth LED from the left.
Step 6. Purpose: Execute and verify an overcurrent test.
Method: Referring to the overcurrent tests previously outlined
in this section, execute an overcurrent test and verify its
operation.
Step 7. Purpose: Verify that the torque-control equation disables the
overcurrent element when deasserted.
Method:
a. Remove the torque-control conditions to deassert the
torque-control equation.
b. For this test example, remove control voltage from
IN101
. Re-execute the same overcurrent test and verify
that it does not operate.
Combined
Overcurrent Elements
The SEL-387 has two sets of combined overcurrent elements. Set EOCC = Y
to enable them. One set uses the sum of currents from Windings 1 and 2, the
other the sum of currents from Windings 3 and 4. Each set has a phase
overcurrent and a residual overcurrent element, both of which are inverse-time
elements using the same curves as the similar Winding 51 elements. The first
set, for Windings 1 and 2, consists of units 51PC1 and 51NC1; the other set,
for Windings 3 and 4, has units 51PC2 and 51NC2.
The test for the combined overcurrent elements is intended to simulate the
application for these elements, namely a ring-bus or breaker-and-a-half
scheme where two sets of CT inputs from two breakers are brought to the
relay. These two inputs are for the same physical winding, whose current is
the phasor sum of the two inputs.
The test configuration is that shown in Figure 10.5 , with two sources
delivering current to the same phase of Windings 1 and 2, or Windings 3
and 4.