GE L90 Instruction Manual page 282

5.6 GROUPED ELEMENTS
D60, L60, and L90 only
FLEXLOGIC OPERANDS
OPEN POLE OP A Ф
OPEN POLE OP B Ф
OPEN POLE OP C Ф
SETTING
GND DIST Z2 FUNCTION
Enabled = 1
Disabled = 0
SETTING
GND DIST Z2 BLK
Off = 0
SETTING
DISTANCE SOURCE
IA-IB
IB-IC
IC-IA
VAG-VBG
VBG-VCG
VCG-VAG
VAB
VBC
VCA
5
I_2
I_0
V_1
I_1
IN
Figure 5–73: GROUND DISTANCE ZONES 2 AND HIGHER SCHEME LOGIC
GROUND DIRECTIONAL SUPERVISION:
A dual (zero-sequence 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 resis-
tance faults.
Ground distance zones 2 and higher 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.
5-146
SETTINGS
GND DIST Z2 DIR
GND DIST Z2 SHAPE
GND DIST Z2 Z0/Z2 MAG
GND DIST Z2 Z0/Z2 ANG
GND DIST Z2 ZOM/Z1 MAG
GND DIST Z2 ZOM/Z1 ANG
GND DIST Z2 REACH
GND DIST Z2 RCA
GND DIST Z2 REV REACH
GND DIST Z2 REV REACH RCA
GND DIST Z2 POL CURRENT
GND DIST Z2 NON-HOMGEN ANG
GND DIST Z2 COMP LIMIT
AND
GND DIST Z2 DIR RCA
GND DIST Z2 DIR COMP LIMIT
GND DIST Z2 VOLT LEVEL
GND DIST Z2 QUAD RGT BLD
GND DIST Z2 QUAD RGT BLD RCA
GND DIST Z2 QUAD LFT BLD
GND DIST Z2 QUAD LFT BLD RCA
RUN
A ELEMENT
RUN
B ELEMENT
RUN
C ELEMENT
MEMORY
TIMER
1 cycle
V_1 > 0.80 pu
OR
I_1 > 0.025 pu
SETTING
GND DIST Z2 SUPV
RUN
| IN | > Pickup
L90 Line Current Differential System
Quadrilateral
characteristic
only
1 cycle
FLEXLOGIC OPERAND
GND DIST Z2 SUPN IN
GND DIST Z2 DIR SUPN
OR
OPEN POLE OP **
** D60, L60, and L90 only
5 SETTINGS
FLEXLOGIC OPERANDS
AND GND DIST Z2 PKP AB
GND DIST Z2 DPO A
FLEXLOGIC OPERANDS
AND GND DIST Z2 PKP B
GND DIST Z2 DPO B
FLEXLOGIC OPERANDS
GND DIST Z2 PKP C
AND
GND DIST Z2 DPO C
FLEXLOGIC OPERAND
GND DIST Z2 PKP
OR
837011AG.CDR
GE Multilin