GE L60, Instruction Manual, Page: 197 / 498

GE Multilin L60 Line Phase Comparison Relay 5-105
5 SETTINGS 5.5 GROUPED ELEMENTS
5
Figure 5–56: GROUND DISTANCE ZONE 2 TO ZONE 3 OP SCHEME
GROUND DIRECTIONAL SUPERVISION:
A dual (zero- and negative-sequence) memory-polarized directional supervision applied to the ground distance protection
elements has been shown to give good directional integrity. However, a reverse double-line-to-ground fault can lead to a
maloperation of the ground element in a sound phase if the zone reach setting is increased to cover high resistance faults.
Ground distance Zones 2 through 3 use an additional ground directional supervision to enhance directional integrity. The
element’s directional characteristic angle is used as a ‘maximum torque angle’ together with a 90° limit angle.
The supervision is biased toward operation in order to avoid compromising the sensitivity of ground distance elements at
low signal levels. Otherwise, the reverse fault condition that generates concern will have high polarizing levels so that a cor-
rect reverse fault decision can be reliably made. The supervision for Zones 2and 3 is removed during open pole conditions.
Figure 5–57: GROUND DIRECTIONAL SUPERVISION SCHEME LOGIC
FLEXLOGIC OPERAND
FLEXLOGIC OPERAND
FLEXLOGIC OPERAND
FLEXLOGIC OPERAND
FLEXLOGIC OPERAND
FLEXLOGIC OPERAND
FLEXLOGIC OPERAND
FLEXLOGIC OPERAND
SETTING
SETTING
SETTING
0
0
0
OR
AND
AND
AND
OR
OR
OR
t
t
t
PKP
PKP
PKP
GND DIST Z2 PKP A
OPEN POLE OP
0
0
0
20 ms
20 ms
20 ms
GND DIST Z2 PKP B
GND DIST Z2 PKP C
GND DIST Z2 OP A
GND DIST Z2 OP B
GND DIST Z2 OP C
GND DIST Z2 OP
GND DIST Z2 DELAY:
GND DIST Z2 DELAY:
GND DIST Z2 DELAY:
837019A6.CDR
FLEXLOGIC OPERAND
FLEXLOGIC OPERAND
SETTING
DISTANCE SOURCE:
V_0 > 5 Volts
RUN
ZERO SEQ
DIRECTIONAL
GND DIST Z2 DIR
SUPN
OPEN POLE OP
V_0
837009A6.CDR
AND
OR
t
t
PKP
RST
CO-ORDINATING TIME
Pickup 4.5 cycles, Reset 1.0 cycle
I_0