GE L60 Instruction Manual page 347

Line phase comparison system
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CHAPTER 5: SETTINGS
The element responds to the magnitude of the I_2 × Z – V_2 voltage term in the signal source associated with the 87PC
function. The impedance factor is controlled by an independent setting. Two voltage thresholds are provided for the low-
set and high-set operation controlling keying and tripping, respectively.
— This setting enables or disables the negative-sequence voltage fault detection. Note that all
NEG SEQ VOL FD FUNCTION
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. This function requires
voltages to operate, and uses the first voltage bank configured in the relay.
For this function to operate correctly, the phase VT bank needs to be configured properly and assigned on source 3 or
source 4. The I_2 × Z – V_2 function cannot be enabled if a phase VT is not assigned at source 3 or 4. In this case this
setting is forced to "Disabled."
— This setting defines the relative magnitude of the I_2 × Z term augmented to the negative-
NEG SEQ VOL FD IMPEDANCE
sequence voltage. The element uses the positive-sequence line impedance—both magnitude and angle—as defined under
SETTINGS  PRODUCT SETUP  FAULT REPORTS  FAULT REPORT
impedance used in the I_2 × Z – V_2 voltage term.
— This setting controls pickup of the low-set stage used to control the key operation. The nominal
NEG SEQ VOL FDL PICKUP
phase-to-ground voltage of the VT bank of the relay is 1 pu. For example, for a phase VT bank configured in wye and
having 63.5 V nominal secondary, or for a phase VT bank configured in delta and having 110 V nominal secondary, 1 pu is
equivalent to 63.5 V.
— This setting controls pickup of the high-set stage used to control the trip operation. The nominal
NEG SEQ VOL FDH PICKUP
phase-to-ground voltage of the VT bank of the relay is 1 pu.
— The fault detector is hard-wired to the 87PC scheme. It can be disabled permanently using the
NEG SEQ VOL FD BLK
function setting or blocked temporarily using this block setting. Indicate a FlexLogic operand to block the negative-
sequence voltage fault detector upon assertion.
— This setting controls the targets of the function. These targets operate independently from the
NEG SEQ VOL FD TARGET
87PC targets.
— This setting controls event recording of the function. These events are logged independently from
NEG SEQ VOL FD EVENTS
the 87PC events.
L60 LINE PHASE COMPARISON SYSTEM – INSTRUCTION MANUAL
NEG SEQ VOL FD BLK:
Off
NEG SEQ VOL FD
TARGET: Self-reset
NEG SEQ VOL FD
EVENTS: Disabled
Figure 5-87: Negative-sequence voltage fault detector logic
Range: any FlexLogic operand
Range: Self-Reset, Latched, Disabled
Range: Disabled, Enabled
. This setting controls the percentage of the line
GROUPED ELEMENTS
5
5-179

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