GE 745 Instruction Manual page 256

PROTECTION SCHEMES
7.5.2.4 Verification of Remote Reset Mode
7.5.2.5 Verification of Solid-state Output
7.5.2.6 Basic Operating Time
7–18
 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.
 Set
S1 745 SETUP
Input 1(16).
 Assert logic input 1.
The target should reset.
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.
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
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.
 Close the switch and set the current level to three (3) times the minimum
pickup value measured earlier.
CHAPTER 7: COMMISSIONING
RESETTING REMOTE RESET SIGNAL
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745 TRANSFORMER PROTECTION SYSTEM – INSTRUCTION MANUAL
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