GE Multilin
L60 Line Phase Comparison System
5-205
5 SETTINGS
5.5 GROUPED ELEMENTS
5
c) NEUTRAL INSTANTANEOUS OVERCURRENT
(ANSI 50N, IEC PIOC)
PATH: SETTINGS
GROUPED ELEMENTS
SETTING GROUP 1(6)
NEUTRAL CURRENT
NEUTRAL IOC1(2)
The neutral instantaneous overcurrent element may be used as an instantaneous function with no intentional delay or as a
definite time function. The element essentially responds to the magnitude of a neutral current fundamental frequency pha-
sor calculated from the phase currents. A positive-sequence restraint is applied for better performance. A small portion
(6.25%) of the positive-sequence current magnitude is subtracted from the zero-sequence current magnitude when forming
the operating quantity of the element as follows:
(EQ 5.18)
The positive-sequence restraint allows for more sensitive settings by counterbalancing spurious zero-sequence currents
resulting from:
•
System unbalances under heavy load conditions
•
Transformation errors of current transformers (CTs) during double-line and three-phase faults.
•
Switch-off transients during double-line and three-phase faults.
The positive-sequence restraint must be considered when testing for pickup accuracy and response time (multiple of
pickup). The operating quantity depends on how test currents are injected into the relay (single-phase injection:
; three-phase pure zero-sequence injection:
).
Figure 5–97: NEUTRAL IOC1 SCHEME LOGIC
NEUTRAL IOC1
NEUTRAL IOC1
FUNCTION: Disabled
Range: Disabled, Enabled
MESSAGE
NEUTRAL IOC1 SIGNAL
SOURCE: SRC 1
Range: SRC 1, SRC 2, SRC 3, SRC 4
MESSAGE
NEUTRAL IOC1
PICKUP: 1.000
pu
Range: 0.000 to 30.000 pu in steps of 0.001
MESSAGE
NEUTRAL IOC1 PICKUP
DELAY: 0.00
s
Range: 0.00 to 600.00 s in steps of 0.01
MESSAGE
NEUTRAL IOC1 RESET
DELAY: 0.00
s
Range: 0.00 to 600.00 s in steps of 0.01
MESSAGE
NEUTRAL IOC1 BLOCK:
Off
Range: FlexLogic operand
MESSAGE
NEUTRAL IOC1
TARGET: Self-reset
Range: Self-reset, Latched, Disabled
MESSAGE
NEUTRAL IOC1
EVENTS: Disabled
Range: Disabled, Enabled
I
op
3
I_0
K
x
I_1
–
=
where
K
1 16
=
I
op
0.9375
x
I
injected
=
I
op
3
I
injected
=
FLEXLOGIC OPERANDS
NEUTRAL IOC1 FUNCTION:
NEUTRAL IOC1 PICKUP:
NEUTRAL IOC1 SOURCE:
NEUTRAL IOC1 BLOCK:
NEUTRAL IOC1 DPO
NEUTRAL IOC1 OP
NEUTRAL IOC1 PKP
RUN
AND
827035A5.CDR
SETTING
SETTING
Enabled=1
SETTING
SETTING
I_0
Off=0
SETTINGS
NEUTRAL IOC1
RESET DELAY :
NEUTRAL IOC1
PICKUP DELAY :
t
PKP
t
RST
3(
I
_0 - K
I
_1 ) PICKUP
Summary of Contents for L60
Page 10: ...x L60 Line Phase Comparison System GE Multilin TABLE OF CONTENTS ...
Page 57: ...GE Multilin L60 Line Phase Comparison System 2 27 2 PRODUCT DESCRIPTION 2 3 SPECIFICATIONS 2 ...
Page 58: ...2 28 L60 Line Phase Comparison System GE Multilin 2 3 SPECIFICATIONS 2 PRODUCT DESCRIPTION 2 ...
Page 482: ...6 26 L60 Line Phase Comparison System GE Multilin 6 5 PRODUCT INFORMATION 6 ACTUAL VALUES 6 ...
Page 554: ...10 8 L60 Line Phase Comparison System GE Multilin 10 2 BATTERIES 10 MAINTENANCE 10 ...
Page 674: ...B 110 L60 Line Phase Comparison System GE Multilin B 4 MEMORY MAPPING APPENDIX B B ...
Page 704: ...C 30 L60 Line Phase Comparison System GE Multilin C 7 LOGICAL NODES APPENDIX C C ...
Page 720: ...E 10 L60 Line Phase Comparison System GE Multilin E 1 PROTOCOL APPENDIX E E ...
Page 732: ...F 12 L60 Line Phase Comparison System GE Multilin F 2 DNP POINT LISTS APPENDIX F F ...
Page 742: ...H 8 L60 Line Phase Comparison System GE Multilin H 3 WARRANTY APPENDIX H H ...