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8 COMMISSIONING
b) VERIFICATION OF LOCAL 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
3.
Press the
key. The target should reset.
RESET
4.
Set
S1 745 SETUP
5.
Press the
key and verify that the target does not reset if the logic input is not asserted. Verify the status of
RESET
selected logic input through the
6.
Assert the selected logic input, apply the current to cause the target to latch and verify that pressing the
does not reset the LED. The following message should appear:
INVALID KEY: MUST
BE IN LOCAL MODE
c) 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
3.
Assert Logic Input 1. The target should reset.
d) 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.
e) BASIC OPERATING TIME
1.
To measure the basic operating time of the harmonic restrained differential elements, 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.
GE Multilin
Courtesy of NationalSwitchgear.com
RESETTING
LOCAL RESET BLOCK
RESETTING
LOCAL RESET BLOCK
A1 STATUS
LOGIC INPUTS
RESETTING
REMOTE RESET SIGNAL
Figure 8–4: SOLID STATE OUTPUT TEST CIRCUIT
745 Transformer Management Relay
8.5 PROTECTION SCHEMES
to "Disabled".
to "Logic Input 1(16)".
LOGIC INPUT 1(16) STATE
to "Logic Input 1(16)".
actual value:
button
RESET
8-13
8
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