Protection Schemes
745
Transformer Management Relay
Commission
ing
http://www.GEindustrial.com/multilin
7–13
GE Multilin
5. Press the
RESET
key and verify that the target does not reset if the logic input is
not asserted. Verify the status of selected logic input through the
A1 STATUS
!"
LOGIC INPUTS
!"
LOGIC INPUT 1(16) STATE
actual value:
6. Assert the selected logic input, apply the current to cause the target to latch
and verify that pressing the
RESET
button does not reset the LED. The following
message should appear:
INVALID KEY: MUST BE IN LOCAL MODE
.
d) Verification of Remote Reset Mode
1. Set the differential element with a latched target. Apply enough current to
cause the relay to operate, then remove the current. The Trip LED and the
Phase LED should be latched on.
2. Set
S1 745 SETUP
!"
RESETTING
!"
REMOTE RESET SIGNAL
to “Logic Input 1(16)”.
3. Assert Logic Input 1. The target should reset.
e) Verification of Solid State Output
1. If the solid state output is used to drive auxiliary relays, verify that these relays
operate whenever the relay is in a trip condition. Ensure that the current though
the auxiliary coils is interrupted by an external contactor between each test.
2. To avoid operating the breaker during the commissioning process when the solid
state output operates the breaker directly, use the circuit shown below to verify
this output. Whenever the relay is in a trip state, current flows through the load
resistor. Select the resistor for approximately 1
×
CT of DC current with the
normal DC supply voltage used in your relay scheme.
FIGURE 7–4: Solid State Output Test Circuit
f) Basic Operating Time
1. To measure the basic operating time of the harmonic restrained differential ele-
ments, connect an AC current signal to Terminals H1 and G1, through a double-
pole single-throw switch. The second pole of the switch starts a timer circuit
which is stopped by the operation of the relay trip contact. Refer to the figure
below for details.
2. Close the switch and set the current level to 3 times the minimum pickup value
measured earlier. Re-open the switch and reset all targets on the relay. Ensure
that timer circuit functions correctly.
3. Close the switch and record operating time of relay.
Summary of Contents for Multilin 745
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