GE Multilin
M60 Motor Protection System
5-185
5 SETTINGS
5.6 GROUPED ELEMENTS
5
b) NEUTRAL INSTANTANEOUS OVERCURRENT
(ANSI 50N, IEC PIOC)
PATH: SETTINGS
GROUPED ELEMENTS
SETTING GROUP 1(6)
NEUTRAL CURRENT
NEUTRAL IOC1(8)
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 5.29)
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 5–88: 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
I_1
–
=
where
K
1 16
=
I
op
0.9375
I
injected
=
I
op
3
I
injected
=
Summary of Contents for M60 UR Series
Page 10: ...x M60 Motor Protection System GE Multilin TABLE OF CONTENTS ...
Page 128: ...4 30 M60 Motor Protection System GE Multilin 4 3 FACEPLATE INTERFACE 4 HUMAN INTERFACES 4 ...
Page 410: ...5 282 M60 Motor Protection System GE Multilin 5 10 TESTING 5 SETTINGS 5 ...
Page 440: ...6 30 M60 Motor Protection System GE Multilin 6 5 PRODUCT INFORMATION 6 ACTUAL VALUES 6 ...
Page 452: ...7 12 M60 Motor Protection System GE Multilin 7 2 TARGETS 7 COMMANDS AND TARGETS 7 ...
Page 462: ...9 8 M60 Motor Protection System GE Multilin 9 2 BATTERIES 9 MAINTENANCE 9 ...
Page 474: ...A 12 M60 Motor Protection System GE Multilin A 1 PARAMETER LISTS APPENDIX A A ...
Page 584: ...B 110 M60 Motor Protection System GE Multilin B 4 MEMORY MAPPING APPENDIX B B ...
Page 614: ...C 30 M60 Motor Protection System GE Multilin C 7 LOGICAL NODES APPENDIX C C ...
Page 630: ...E 10 M60 Motor Protection System GE Multilin E 1 IEC 60870 5 104 PROTOCOL APPENDIX E E ...
Page 642: ...F 12 M60 Motor Protection System GE Multilin F 2 DNP POINT LISTS APPENDIX F F ...
Page 644: ...G 2 M60 Motor Protection System GE Multilin G 1 RADIUS SERVER CONFIGURATION APPENDIX G G ...
Page 652: ...H 8 M60 Motor Protection System GE Multilin H 3 WARRANTY APPENDIX H H ...
Page 662: ...x M60 Motor Protection System GE Multilin INDEX ...