Protection Schemes
745
Transformer Management Relay
Commission
ing
http://www.GEindustrial.com/multilin
7–23
GE Multilin
2. Check that, when the element operates, the Trip and Pickup LEDs are on and
one of the following messages is displayed:
LATCHED a: W1 Ntrl Inst OC 1
or
OPERATED a: W1 Ntrl Inst OC 1
3. Reduce the current until the element resets. The reset level should be 97% of
the operate level. When the element resets, the Trip and Message LEDs should
remain on if the
W1 NEUTRAL INST OC 1 TARGET
was selected as “Latched”.
Otherwise only the Trip LED should stay on.
4. Reset indicators and clear messages.
d) Operating Time
With the setup shown in FIGURE 7–9: General Test Setup on page 7–18 and the
Interval Timer enabled, set the current level to 1.5 times the operate level of the
element and apply suddenly by closing the double-pole switch. Record the operate
time and compare to the
S4 ELEMENTS
!"
NEUTRAL OC
!"
W1 NTRL INST OC 1
!"
W1
NEUTRAL INST OC 1 DELAY
value.
e) Winding 2 and 3 Elements
Because the Winding 2 and 3 elements can be set with completely different
parameters than the Winding 1 elements, it is necessary to repeat the full set of
tests described in this section for each winding.
Only two Neutral Instantaneous Overcurrent 1 elements can be in service
simultaneously.
The blocking from logic input, if enabled, can be tested as described in
earlier tests for other elements.
Neutral Instantaneous
Overcurrent 2
The Neutral Instantaneous Overcurrent 2 elements are identical to the Neutral
Instantaneous Overcurrent 1 elements. Consequently, the same test procedure can
be used to verify their correct operation. Disable all protection features except
Neutral Instantaneous Overcurrent 2 and follow the steps in the previous section,
making the appropriate changes for the LEDs and output relays operated by the
Neutral Instantaneous Overcurrent 2 elements.
Ground Time
Overcurrent
a) Description
This procedure verifies that the Ground Time Overcurrent performance matches the
in-service settings. Since these elements can be assigned a multitude of timing
curves, a table of expected operating times versus applied current should be
prepared prior to testing. The ground element measures the current signal
connected to the ground current input CT, H10 and G10 or F12 and E12. Refer to
on page 5–50 for information on timing curves. There can
only be one or two Ground Time Overcurrent elements in service at the same time.
If the relay elements are set for the “Linear” reset characteristic when measuring
the operating times, ensure there is sufficient time between test current injections
for the element to reset fully. Otherwise, erroneous timing measurements will be
obtained. The settings for these elements will be found under the
S4 ELEMENTS
!"
GROUND OC
!
W1 GND TIME OC
setpoints menu.
b) Winding 1 Element
To ensure that only the Ground Time Overcurrent element operates the trip relays
(and any other output relays) selected by the logic, disable all protection features
except Ground Time Overcurrent. Use the general test setup shown in FIGURE 7–9:
General Test Setup on page 7–18.
Connect the current supply to terminals X = H10 and Y = G10 to test the Winding 1
ground element. Monitor the appropriate output relays as per the relay FlexLogic™
settings.
NOTE
NOTE
Summary of Contents for Multilin 745
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