GE L60 Instructions Manual page 408

GROUPED ELEMENTS
5.6.3.3 Advanced fault detectors
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SETTINGS  GROUPED ELEMENTS  SETTING GROUP 1(6)  PHASE COMPARISON ELEMENTS  ADVANCED FAULT
DETECTORS
 ADVANCED
 FAULT DETECTORS
Five advanced fault detectors are provided, which are supervised by the condition that the magnitude of mixed current
has to be above 0.02 pu.
The negative-sequence voltage element responds to the I × Z – V term for negative-sequence voltage and current and is
meant to detect faults under weak system conditions.
The negative-sequence current rate of change element responds to the vector difference of the negative-sequence
current over a half-a-cycle moving data window, and is meant to detect faults under load unbalance, such as on
5
untransposed high voltage transmission lines or in a vicinity of electrical traction systems causing significant negative-
sequence current unbalance.
The positive-sequence current rate of change element responds to the vector difference of the positive-sequence current
over a half-a-cycle moving data window, and it is meant to detect three-phase balance faults under high load conditions.
The negative-sequence current overcurrent element responds to the increment of the negative-sequence current above
threshold.
The positive-sequence current overcurrent element responds to the increment of the positive-sequence current above
threshold.
All advanced fault detectors operate independently from each other, and independently from the mixed signal overcurrent
FDL and FDH comparators embedded in the 87PC function. Each detector supports the low and high setting levels to
facilitate starting and supervise tripping. When enabled, a given detector is automatically used to control the 87PC
function. Effectively all detectors are ORed before they are routed to the 87PC element.
The overcurrent fault detectors respond to the effective operating current of the 87PC function, which includes charging
current compensation. The advanced fault detectors respond to their operating signals irrespective of the configured 87PC
current.
5.6.3.4 Negative-sequence voltage fault detection
SETTINGS  GROUPED ELEMENTS  SETTING GROUP 1(6)  PHASE COMPARISON ELEMENTS  ADVANCED FAULT
DETECTORS  NEGATIVE SEQUENCE VOLTAGE
 NEGATIVE SEQUENCE
 VOLTAGE
5-200
 NEGATIVE SEQUENCE

 VOLTAGE
 RATE OF CHANGE OF

 NEG SEQ CURRENT
 RATE OF CHANGE OF

 POS SEQ CURRENT
 NEGATIVE SEQUENCE

 CURRENT
 POSITIVE SEQUENCE

 CURRENT
NEG SEQ VOL FD

FUNCTION: Disabled
NEG SEQ VOL FD

IMPEDANCE: 10.0%
NEG SEQ VOL FDL

PICKUP: 0.010 pu
NEG SEQ VOL FDH

PICKUP: 0.050 pu
See below
See page 5-202
See page 5-203
See page 5-204
See page 5-205
Range: Disabled, Enabled
Range: 0.0 to 100% in steps of 0.1
Range: 0.005 to 3.000 pu in steps of 0.001
Range: 0.005 to 3.000 pu in steps of 0.001
L60 LINE PHASE COMPARISON SYSTEM – INSTRUCTION MANUAL
CHAPTER 5: SETTINGS