GE L60 Instruction Manual page 348

GROUPED ELEMENTS
5.6.3.5 Rate of change of negative-sequence current fault detection
SETTINGS  GROUPED ELEMENTS  SETTING GROUP 1(6)  PHASE COMPARISON ELEMENTS  ADVANCED FAULT
DETECTORS  RATE OF CHANGE OF NEG SEQ CURRENT
 RATE OF CHANGE OF
 NEG SEQ CURRENT
5
The element responds to the vector difference of the negative-sequence current phasors taken at the present moment
and one-half a power system cycle earlier. Two current thresholds are provided for the low-set and high-set operation
controlling keying and tripping. The raw di / dt condition of the element detects the change and resets when reaching a
steady state fault condition. As such, a seal-in timer is provided to maintain the detected fault condition for a user
specified period of time.
NEG SEQ di/dt FD FUNCTION
detection. Note that all fault detectors operate in parallel toward the 87PC function. If not required, disable a given fault
detector. To effectively disable the overcurrent fault detectors under the main 87PC menu, set their threshold very high.
NEG SEQ di/dt FDL PICKUP
operation. The nominal current of the phase CT bank of the relay is 1 pu.
NEG SEQ di/dt FDL SEAL-IN
terminals of the line, the timer is started at the rising edge of the raw di / dt condition.
NEG SEQ di/dt FDH PICKUP
operation. The nominal current of the phase CT bank of the relay is 1 pu.
NEG SEQ di/dt FDH SEAL-IN
terminals of the line, the timer is started at the rising edge of the raw di / dt condition. In this way, the fault detectors reset
approximately at the same time at all line terminals, regardless of responses of individual raw conditions potentially
different at different line terminals.
NEG SEQ FDH SUPV
faults starting as non-symmetrical defined by the
function typically is assigned with this setting.
— Note that the fault detector is hard-wired to the 87PC scheme. It can be disabled permanently using
NEG SEQ di/dt BLK
the function setting or blocked temporarily using this block setting. Select a FlexLogic operand that, if asserted, blocks this
fault detector.
NEG SEQ di/dt FD TARGET
targets.
NEG SEQ di/dt FD EVENTS
from the 87PC events.
5-180
NEG SEQ di/dt FD

FUNCTION: Disabled
NEG SEQ di/dt FDL

PICKUP: 0.10 pu
NEG SEQ di/dt FDL

SEAL-IN: 0.600 s
NEG SEQ di/dt FDH

PICKUP: 0.50 pu
NEG SEQ di/dt FDH

SEAL-IN: 0.200 s
NEG SEQ FDH SUPV:

Off
NEG SEQ di/dt BLK:

Off
NEG SEQ di/dt FD

TARGET: Self-reset
NEG SEQ di/dt FD

EVENTS: Disabled
— This setting enables or disables the rate of change of negative-sequence current fault
— This setting controls pickup of the low set stage of the element used to control the key
— This setting defines seal-in time of the FDL function. To equalize the response between all
— This setting controls pickup of the high set stage of the element used to control the trip
— This setting defines seal-in time of the FDH function. To equalize the response between all
— This setting provides seal-in control of the FDH function for the symmetrical external three-phase
— This setting controls targets of the function. These targets operate independently from the 87PC
— This setting controls event recording of the function. These events are logged independently
Range: Disabled, Enabled
Range: 0.01 to 5.00 pu in steps of 0.01
Range: 0.000 to 10.000 s in steps of 0.001
Range: 0.01 to 5.00 pu in steps of 0.01
Range: 0.000 to 10.000 s in steps of 0.001
Range: any FlexLogic operand
Range: any FlexLogic operand
Range: Self-Reset, Latched, Disabled
Range: Disabled, Enabled
setting time. The overreaching distance
NEG SEQ di/dt FDH SEAL-IN
L60 LINE PHASE COMPARISON SYSTEM – INSTRUCTION MANUAL
CHAPTER 5: SETTINGS