5.6 GROUPED ELEMENTS
Figure 5–96: LOAD ENCROACHMENT APPLIED TO DISTANCE ELEMENT
•
LOAD ENCROACHMENT MIN VOLT: This setting specifies the minimum positive-sequence voltage required for oper-
ation of the element. If the voltage is below this threshold a blocking signal will not be asserted by the element. When
selecting this setting one must remember that the T60 measures the phase-to-ground sequence voltages regardless of
the VT connection.
The nominal VT secondary voltage as specified with the
setting is the per-unit base for this setting.
VT SECONDARY
5
•
LOAD ENCROACHMENT REACH: This setting specifies the resistive reach of the element as shown in the Load
encroachment characteristic diagram. This setting should be entered in secondary ohms and be calculated as the pos-
itive-sequence resistance seen by the relay under maximum load conditions and unity power factor.
•
LOAD ENCROACHMENT ANGLE: This setting specifies the size of the blocking region as shown on the Load
encroachment characteristic diagram and applies to the positive-sequence impedance.
5-200
X
SYSTEM SETUP
Figure 5–97: LOAD ENCROACHMENT SCHEME LOGIC
T60 Transformer Protection System
R
837731A1.CDR
AC INPUTS
VOLTAGE BANK X5
5 SETTINGS
PHASE
GE Multilin