GE G60 UR Series, Instruction Manual

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5-134 G60 Generator Protection System GE Multilin
5.6 GROUPED ELEMENTS 5 SETTINGS
5
The power swing detect element provides both power swing blocking and out-of-step tripping functions. The element mea-
sures the positive-sequence apparent impedance and traces its locus with respect to either two or three user-selectable
operating characteristic boundaries. Upon detecting appropriate timing relations, the blocking and tripping indications are
given through FlexLogic™ operands. The element incorporates an adaptive disturbance detector. This function does not
trigger on power swings, but is capable of detecting faster disturbances – faults in particular – that may occur during power
swings. Operation of this dedicated disturbance detector is signaled via the
POWER SWING 50DD
operand.
The power swing detect element asserts two outputs intended for blocking selected protection elements on power swings:
POWER SWING BLOCK
is a traditional signal that is safely asserted for the entire duration of the power swing, and
POWER
SWING UN/BLOCK
is established in the same way, but resets when an extra disturbance is detected during the power swing.
The
POWER SWING UN/BLOCK
operand may be used for blocking selected protection elements if the intent is to respond to
faults during power swing conditions.
Different protection elements respond differently to power swings. If tripping is required for faults during power swing condi-
tions, some elements may be blocked permanently (using the
POWER SWING BLOCK
operand), and others may be blocked
and dynamically unblocked upon fault detection (using the
POWER SWING UN/BLOCK
operand).
The operating characteristic and logic figures should be viewed along with the following discussion to develop an under-
standing of the operation of the element.
The power swing detect element operates in three-step or two-step mode:
• Three-step operation: The power swing blocking sequence essentially times the passage of the locus of the positive-
sequence impedance between the outer and the middle characteristic boundaries. If the locus enters the outer charac-
teristic (indicated by the
POWER SWING OUTER
FlexLogic™ operand) but stays outside the middle characteristic (indi-
cated by the
POWER SWING MIDDLE
FlexLogic™ operand) for an interval longer than
POWER SWING PICKUP DELAY 1
,
the power swing blocking signal (
POWER SWING BLOCK
FlexLogic™ operand) is established and sealed-in. The block-
ing signal resets when the locus leaves the outer characteristic, but not sooner than the
POWER SWING RESET DELAY 1
time.
• Two-step operation: If the two-step mode is selected, the sequence is identical, but it is the outer and inner character-
istics that are used to time the power swing locus.
MESSAGE
POWER SWING INNER
LFT BLD: 100.00
Ω
Range: 0.10 to 500.00 ohms in steps of 0.01
MESSAGE
POWER SWING PICKUP
DELAY 1: 0.030 s
Range: 0.000 to 65.535 s in steps of 0.001
MESSAGE
POWER SWING RESET
DELAY 1: 0.050 s
Range: 0.000 to 65.535 s in steps of 0.001
MESSAGE
POWER SWING PICKUP
DELAY 2: 0.017 s
Range: 0.000 to 65.535 s in steps of 0.001
MESSAGE
POWER SWING PICKUP
DELAY 3: 0.009 s
Range: 0.000 to 65.535 s in steps of 0.001
MESSAGE
POWER SWING PICKUP
DELAY 4: 0.017 s
Range: 0.000 to 65.535 s in steps of 0.001
MESSAGE
POWER SWING SEAL-IN
DELAY: 0.400 s
Range: 0.000 to 65.535 s in steps of 0.001
MESSAGE
POWER SWING TRIP
MODE: Delayed
Range: Early, Delayed
MESSAGE
POWER SWING BLK:
Off
Range: Flexlogic™ operand
MESSAGE
POWER SWING
TARGET: Self-Reset
Range: Self-Reset, Latched, Disabled
MESSAGE
POWER SWING
EVENTS: Disabled
Range: Disabled, Enabled