5-288
L90 LINE CURRENT DIFFERENTIAL SYSTEM – INSTRUCTION MANUAL
GROUPED ELEMENTS
CHAPTER 5: SETTINGS
5
The negative-sequence instantaneous overcurrent element can be used as an instantaneous function with no intentional
delay or as a definite time function. The element responds to the negative-sequence current fundamental frequency
phasor magnitude (calculated from the phase currents) and applies a positive-sequence restraint for better performance:
a small portion (12.5%) of the positive-sequence current magnitude is subtracted from the negative-sequence current
magnitude when forming the operating quantity.
I
op
= |I_2| - K x |I_1| where K = 1/8
Eq. 5-34
The positive-sequence restraint allows for more sensitive settings by counterbalancing spurious negative-sequence
currents resulting from
•
System unbalances under heavy load conditions
•
Transformation errors of current transformers (CTs) during three-phase faults
•
Fault inception and switch-off transients during 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 the test currents are injected into the relay (single-phase injection:
I
op
= 0.2917 x I
injected
; three-phase injection, opposite rotation: I
op
= I
injected
).
Figure 5-158: Negative sequence IOC1 logic
5.7.12.4 Negative sequence directional overcurrent (ANSI 67Q, IEC PDEF/PTOC)
SETTINGS
GROUPED ELEMENTS
SETTING GROUP 1(6)
NEGATIVE SEQUENCE CURRENT
NEG SEQ DIR
OC1(2)
NEG SEQ IOC1 RESET
DELAY: 0.00 s
Range: 0.00 to 600.00 s in steps of 0.01
NEG SEQ IOC1 BLOCK:
Off
Range: FlexLogic operand
NEG SEQ IOC1
TARGET: Self-reset
Range: Self-reset, Latched, Disabled
NEG SEQ IOC1
EVENTS: Disabled
Range: Disabled, Enabled
NEG SEQ DIR OC1
NEG SEQ DIR OC1
FUNCTION: Disabled
Range: Disabled, Enabled
NEG SEQ DIR OC1
SOURCE: SRC 1
Range: SRC 1, SRC 2, SRC 3, SRC 4
NEG SEQ DIR OC1
OFFSET: 0.00
Ω
Range: 0.00 to 250.00 ohms in steps of 0.01
NEG SEQ DIR OC1
TYPE: Neg Sequence
Range: Neg Sequence, Zero Sequence
Содержание L90
Страница 14: ...1 4 L90 LINE CURRENT DIFFERENTIAL SYSTEM INSTRUCTION MANUAL FOR FURTHER ASSISTANCE CHAPTER 1 INTRODUCTION 1 ...
Страница 68: ...2 54 L90 LINE CURRENT DIFFERENTIAL SYSTEM INSTRUCTION MANUAL SPECIFICATIONS CHAPTER 2 PRODUCT DESCRIPTION 2 ...
Страница 136: ...3 68 L90 LINE CURRENT DIFFERENTIAL SYSTEM INSTRUCTION MANUAL CONNECT TO D400 GATEWAY CHAPTER 3 INSTALLATION 3 ...
Страница 224: ...4 88 L90 LINE CURRENT DIFFERENTIAL SYSTEM INSTRUCTION MANUAL FLEXLOGIC DESIGN USING ENGINEER CHAPTER 4 INTERFACES 4 ...
Страница 692: ...6 36 L90 LINE CURRENT DIFFERENTIAL SYSTEM INSTRUCTION MANUAL PRODUCT INFORMATION CHAPTER 6 ACTUAL VALUES 6 ...
Страница 708: ...7 16 L90 LINE CURRENT DIFFERENTIAL SYSTEM INSTRUCTION MANUAL TARGETS MENU CHAPTER 7 COMMANDS AND TARGETS 7 ...
Страница 742: ...9 6 L90 LINE CURRENT DIFFERENTIAL SYSTEM INSTRUCTION MANUAL TESTING CHAPTER 9 COMMISSIONING 9 ...
Страница 804: ...10 62 L90 LINE CURRENT DIFFERENTIAL SYSTEM INSTRUCTION MANUAL FAULT LOCATOR CHAPTER 10 THEORY OF OPERATION 10 ...
Страница 872: ...C 6 L90 LINE CURRENT DIFFERENTIAL SYSTEM INSTRUCTION MANUAL COMMAND LINE INTERFACE APPENDIX C COMMAND LINE INTERFACE C ...
Страница 878: ...D 6 L90 LINE CURRENT DIFFERENTIAL SYSTEM INSTRUCTION MANUAL REVISION HISTORY APPENDIX D MISCELLANEOUS D ...
Страница 882: ...iv L90 LINE CURRENT DIFFERENTIAL SYSTEM INSTRUCTION MANUAL ABBREVIATIONS ...
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