GE Multilin
T60 Transformer Protection System
5-245
5 SETTINGS
5.6 GROUPED ELEMENTS
5
Figure 5–115: GROUND IOC1 SCHEME LOGIC
d) RESTRICTED GROUND FAULT
(ANSI 87RGF, IEC PNDF)
PATH: SETTINGS
GROUPED ELEMENTS
SETTING GROUP 1(6)
GROUND CURRENT
RESTRICTED GROUND FAULT 1(6)
As of T60 firmware revision 3.20, the definition of the restraining signal has been significantly changed
compared to previous versions. The restraint during external faults is generally not lower, and often much
higher, compared to the previous definition of the restraining signal (enhanced security). The restraint on
internal faults has been greatly reduced compared to previous versions (enhanced sensitivity), particularly
during low-current internal faults. Using time delay as a means of dealing with CT saturation is no longer
obligatory; pickup and slope are the primary means of addressing CT saturation. Increasing the slope set-
ting is recommended when migrating from the 3.1x or earlier firmware revisions. The default value for the
slope has been changed from 10% to 40%.
Restricted ground fault (RGF) protection provides sensitive ground fault detection for low-magnitude fault currents, primar-
ily faults close to the neutral point of a wye-connected winding. An internal ground fault on an impedance grounded wye
winding will produce a fault current dependent on the ground impedance value and the fault position on the winding with
respect to the neutral point. The resultant primary current will be negligible for faults on the lower 30% of the winding since
the fault voltage is not the system voltage, but rather the result of the transformation ratio between the primary windings
RESTRICTED GROUND
FAULT 1
RESTD GND FT1
FUNCTION: Disabled
Range: Disabled, Enabled
MESSAGE
RESTD GND FT1
SOURCE: SRC 1
Range: SRC 1, SRC 2, SRC 3, SRC 4, SRC 5, SRC 6
MESSAGE
RESTD GND FT1
PICKUP: 0.080
pu
Range: 0.005 to 30.000 pu in steps of 0.001
MESSAGE
RESTD GND FT1
SLOPE: 40%
Range: 0 to 100% in steps of 1
MESSAGE
RESTD GND FT1 PICKUP
DELAY: 0.10
s
Range: 0.00 to 600.00 s in steps of 0.01
MESSAGE
RESTD GND FT1 RESET
DELAY: 0.00 s
Range: 0.00 to 600.00 s in steps of 0.01
MESSAGE
RESTD GND FT1 BLOCK:
Off
Range: FlexLogic operand
MESSAGE
RESTD GND FT1
TARGET: Self-reset
Range: Self-reset, Latched, Disabled
MESSAGE
RESTD GND FT1
EVENTS: Disabled
Range: Disabled, Enabled
SETTING
GROUND IOC1
FUNCTION:
Enabled = 1
SETTING
GROUND IOC1
SOURCE:
IG
GROUND IOC1
BLOCK:
Off = 0
FLEXLOGIC OPERANDS
GROUND IOIC DPO
GROUND IOC1 OP
SETTING
SETTING
IG
PICKUP
GROUND IOC1
PICKUP:
RUN
GROUND IOC1 PICKUP
DELAY:
SETTINGS
GROUND IOC1 RESET
DELAY:
t
PKP
t
RST
827037A5.VSD
AND
GROUND IOC1 PKP
NOTE
Summary of Contents for T60
Page 6: ...vi T60 Transformer Protection System GE Multilin TABLE OF CONTENTS ...
Page 14: ...xiv T60 Transformer Protection System GE Multilin TABLE OF CONTENTS ...
Page 34: ...1 20 T60 Transformer Protection System GE Multilin 1 5 USING THE RELAY 1 GETTING STARTED 1 ...
Page 490: ...5 344 T60 Transformer Protection System GE Multilin 5 10 TESTING 5 SETTINGS 5 ...
Page 522: ...6 32 T60 Transformer Protection System GE Multilin 6 5 PRODUCT INFORMATION 6 ACTUAL VALUES 6 ...
Page 536: ...7 14 T60 Transformer Protection System GE Multilin 7 1 COMMANDS 7 COMMANDS AND TARGETS 7 ...
Page 568: ...10 12 T60 Transformer Protection System GE Multilin 10 6 DISPOSAL 10 MAINTENANCE 10 ...
Page 596: ...A 28 T60 Transformer Protection System GE Multilin A 1 PARAMETER LISTS APPENDIX A A ...
Page 716: ...B 120 T60 Transformer Protection System GE Multilin B 4 MEMORY MAPPING APPENDIX B B ...
Page 762: ...E 10 T60 Transformer Protection System GE Multilin E 1 IEC 60870 5 104 PROTOCOL APPENDIX E E ...
Page 774: ...F 12 T60 Transformer Protection System GE Multilin F 2 DNP POINT LISTS APPENDIX F F ...