GE N60 Instruction Manual page 358

GROUPED ELEMENTS CHAPTER 5: SETTINGS
— Controls the out-of-step tripping function only. It defines the interval the impedance locus
POWER SWING PICKUP DELAY 3
must spend within the inner characteristic before the last step of the out-of-step tripping sequence is completed and the
element is armed to trip. The actual moment of tripping is controlled by the setting. This time delay is provided
TRIP MODE
for extra security before the out-of-step trip action is executed.
— Controls the out-of-step tripping function in "Delayed" trip mode only. This timer defines
POWER SWING PICKUP DELAY 4
the interval the impedance locus must spend outside the inner characteristic but within the outer characteristic before the
element is armed for the delayed trip. The delayed trip occurs when the impedance leaves the outer characteristic. This
time delay is provided for extra security. Set it considering the fastest expected power swing.
— The out-of-step trip FlexLogic operand (POWER SWING TRIP) is sealed-in for the specified
POWER SWING SEAL-IN DELAY
period of time. The sealing-in is crucial in the delayed trip mode, as the original trip signal is a very short pulse occurring
when the impedance locus leaves the outer characteristic after the out-of-step sequence is completed.
— Selection of the "Early" trip mode results in an instantaneous trip after the last step in the out-
POWER SWING TRIP MODE
of-step tripping sequence is completed. The early trip mode stresses the circuit breakers as the currents at that moment
are high (the electromotive forces of the two equivalent systems are approximately 180° apart). Selection of the "Delayed"
trip mode results in a trip at the moment when the impedance locus leaves the outer characteristic. Delayed trip mode
relaxes the operating conditions for the breakers as the currents at that moment are low. Make the selection considering
the capability of the breakers in the system.
— This setting specifies the FlexLogic operand used for blocking the out-of-step function only. The
POWER SWING BLK
power swing blocking function is operational all the time as long as the element is enabled. The blocking signal resets the
output operand but does not stop the out-of-step tripping sequence.
POWER SWING TRIP
— Enables and disables the logging of power swing detect events in the sequence of events
POWER SWING EVENTS
recorder.
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5-198 N60 NETWORK STABILITY AND SYNCHROPHASOR MEASUREMENT SYSTEM – INSTRUCTION MANUAL