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Protection Schemes
NOTE
Ground Instantaneous
Overcurrent 1
NOTE
NOTE
GE Multilin
To test the second element, disable all protection elements except for the
GROUND TIME OVERCURRENT
current signal to X = F12 and Y = E12. Repeat all the tests described for the
Winding 1 Ground Time Overcurrent element in this section.
The blocking from logic input, if enabled, can be tested as described in
earlier tests for other elements.
a) Description
This procedure verifies that the Ground Instantaneous Overcurrent performance
matches the in-service settings. Settings for these elements are found under the
ELEMENTS
GROUND OC
!"
!"
require you to test at current multiples of several times the rated CT secondary
value do not leave the current signal on for more than a few seconds.
b) Winding 1 Element
To ensure only the Ground IOC 1 element operates the trip relays (and any other
output relays) selected by the logic, disable all protection features except Ground
IOC 1. 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
element. Monitor the appropriate output relays as per the relay FlexLogic™ settings.
c) Pickup Level
1.
With the interval timer disabled, apply the current signal and increase its mag-
nitude until the trip relay (and all the selected auxiliary relays) operate. Com-
pare the measured operating level against the
W1 GND INST OC 1
!"
W1 GND INST OC 1 PICKUP
2.
When the element operates, check that the Trip and Message LEDs are flashing
and one of the following messages is displayed:
LATCHED a: W1 Gnd Inst OC 1 or OPERATED a: W1 Gnd 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, Ground, and Message LEDs
should remain on if the
Otherwise, only the Trip LED should stay on.
4.
Reset indicators and clear messages.
d) Operating Time
Using the setup shown in FIGURE 7–9: General Test Setup on page 7–18 with the
Interval Timer enabled, set the current level to 1.5 times the element operate level
and apply suddenly by closing the double-pole switch. Record the operate time and
compare to the
S4 ELEMENTS
setting value.
1 DELAY
e) Winding 2 or 3 Element
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 Ground 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.
http://www.GEindustrial.com/multilin
Transformer Management Relay
(or
W3 GROUND TIME OVERCURRENT
setpoints menu. If your relay settings
W1 GND INST OC 1
S4 ELEMENTS
setpoint.
W1 GND INST OC 1 TARGET
!"
GROUND OC
!"
#
W1 GND INST OC 1
745
W2
) element. Connect the
S4
!"
GROUND OC
!"
was selected as "Latched".
!"
W1 GND INST OC
7–25
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