Phase Overcurrent - GE TRANSFORMER MANAGEMENT RELAY 745 Instruction Manual

5 SETPOINTS
a) MAIN MENU
PATH: SETPOINTS S4 ELEMENTS
PHASE OC
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This section contains settings to configure the phase overcurrent elements. Included are phase time overcurrents and two
levels of phase instantaneous overcurrent for each phase of each winding.
b) TIME OVERCURRENT CURVES
The inverse time overcurrent curves used by the TOC (time overcurrent) elements are the ANSI, IEC, and GE Type IAC
curve shapes. This allows for simplified coordination with downstream devices. If however, none of these curve shapes is
adequate, FlexCurves™ may be used to customize the inverse time curve characteristics. The Definite Time curve is also
an option that may be appropriate if only simple protection is required.
Table 5–4: TIME OVERCURRENT CURVE TYPES
ANSI
ANSI Extremely Inverse
ANSI Very Inverse
ANSI Normally Inverse
ANSI Moderately Inverse
A time dial multiplier setting allows selection of a multiple of the base curve shape (where the time dial multiplier = 1) with
the curve shape (
SHAPE
to the time multiplier (
TIME OC MULTIPLIER
plier 1 or base curve values. Setting the multiplier to zero results in an instantaneous response to all current levels above
pickup.
Graphs of standard time-current curves on 11"
the GE Multilin literature department. The original files are also available in PDF format on the UR Software
NOTE Installation CD and the GE Multilin Web Page.
GE Multilin
Courtesy of NationalSwitchgear.com
PHASE OC
ð
W1 PHASE TIME OC
ENTER
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ESCAPE
W2 PHASE TIME OC
ESCAPE
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MESSAGE
W3 PHASE TIME OC
ESCAPE
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MESSAGE
W1 PHASE INST OC 1
ESCAPE
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MESSAGE
W2 PHASE INST OC 1
ESCAPE
[ENTER] for more
MESSAGE
W3 PHASE INST OC 1
ESCAPE
[ENTER] for more
MESSAGE
W1 PHASE INST OC 2
ESCAPE
[ENTER] for more
MESSAGE
W2 PHASE INST OC 2
ESCAPE
[ENTER] for more
MESSAGE
W3 PHASE INST OC 2
ESCAPE
[ENTER] for more
MESSAGE
IEC
IEC Curve A (BS142)
IEC Curve B (BS142)
IEC Curve C (BS142)
IEC Short Inverse
) setting. Unlike the electromechanical time dial equivalent, operate times are directly proportional
) setting value. For example, all times for a multiplier of 10 are 10 times the multi-
745 Transformer Management Relay
See page 5–53.
See page 5–53.
See page 5–53.
See page 5–55.
See page 5–55.
See page 5–55.
See page 5–55.
See page 5–55.
See page 5–55.
GE TYPE IAC
IAC Extremely Inverse
IAC Very Inverse
IAC Inverse
IAC Short Inverse
17" log-log graph paper are available upon request from
×
5.6 S4 ELEMENTS

5.6.5 PHASE OVERCURRENT

OTHER
FlexCurve™ A
FlexCurve™ B
FlexCurve™ C
Definite Time
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