GE F60 Instruction Manual page 429

CHAPTER 5: SETTINGS GROUPED ELEMENTS
Figure 5-111: Load encroachment characteristic
The element operates if the positive-sequence voltage is above a settable level and asserts its output signal that can be
used to block selected protection elements, such as distance or phase overcurrent. The following figure shows an effect of
the load encroachment characteristics used to block the quadrilateral distance element.
Figure 5-112: Load encroachment applied to distance element
5
— This setting specifies the minimum positive-sequence voltage required for operation of
LOAD ENCROACHMENT MIN VOLT
the element. When the voltage is below this threshold, a blocking signal is not asserted by the element. When selecting
this setting, remember that the F60 measures the phase-to-ground sequence voltages regardless of the VT connection.
The nominal VT secondary voltage as specified with the
SYSTEM SETUP  AC INPUTS  VOLTAGE BANK X5  PHASE VT
setting is the per-unit base for this setting.
SECONDARY
— This setting specifies the resistive reach of the element as shown in the Load
LOAD ENCROACHMENT REACH
Encroachment Characteristic diagram. Enter this setting in secondary ohms and calculate it as the positive-sequence
resistance seen by the relay under maximum load conditions and unity power factor.
— This setting specifies the size of the blocking region as shown on the Load Encroachment
LOAD ENCROACHMENT ANGLE
Characteristic diagram and applies to the positive-sequence impedance.
F60 FEEDER PROTECTION SYSTEM – INSTRUCTION MANUAL 5-215