ground distance protection
TRANSCRIPT
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Copyright © FPL and SEL 2015
Breaker Pole Scatter
and Its Effect on !adrilateral"ro!nd #istance Protection
James Ryan,Florida Power & Light Company
Arun Shrestha and Thanh-Xuan Nguyen,Schweitzer Engineering Laboratories, Inc.
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$!tline
• Breaker pole scatter
• Zone 1 challenges hen protect!ng
short l!nes
• "uadr!lateral d!stance element
• #ase study
• Solut!on and test results
• #onclus!on
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Fa!lt Clearing %i&e
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'or&al Breaker Pole Scatter
B# $ault current!nterrupt!on
Normal load current
!nterrupt!on
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(igh Breaker Pole Scatter
%elayed &hase #current !nterrupt!on
'rare(
AB $ault current
!nterrupt!on
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Factors )ffecting Breaker Pole Scatter
• Breaker operat!ng mechan!sm
• %!electr!c strength o$ arc !nterrupters
•)*ternal c!rcu!t parameters dur!ng $ault
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Protection of Short Lines
• +ault res!stance can e s!gn!$!cantly h!gherthan l!ne !mpedance
• ho ground d!stance elements ha.e
l!m!ted $ault res!stance co.erage
• "uadr!lateral ground d!stance elements
are pre$erred
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Fa!lt on Short %rans&ission Line
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!adrilateral "ro!nd #istance Ele&ent
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Factors %hat *ay )ffect !adrilateral
"ro!nd #istance Ele&ent
• /pen-pole cond!t!ons
• Breaker pole scatter
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Case St!dy
• Study e$$ect o$ B0 pole scatter on relay at B1
• Test cases 'B0(
♦ Normal $ault current !nterrupt!on
♦ nterrupt!on delayed y 234 cycles !n one pole
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'or&al Fa!lt Interr!ptionB!s +
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Interr!ption #elayed ,y 0-5 Cycles
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Interr!ption #elayed ,y 0-5 CyclesB!s +
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Interr!ption #elayed ,y 0-5 CyclesB!s .
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+one 1 B" /eactance and
/esistance Calc!lation
5hen +SB asserts, relay !ssues tr!p command to reakers
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FPL Syste&
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Sit!ation Leading to
nintended $peration
• 6!gh reaker pole scatter o$
234 cycles 'rare(
• Strong sources at oth ends'SR 7 132(
• 8ery short l!nes
• 9arge res!st!.e co.erage $or :uadr!lateralground d!stance elements
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FPL nintended $peration
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+one 1 B" /eactance and
/esistance Calc!lation
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Proposed Sol!tion
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C$*%/)#E Play,ack %est
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/%#S %est /e&ote Fa!lt
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/%#S %est +one 1 Fa!lt
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Concl!sion
• 6!gh reaker pole scatter may occur asreakers ear and age
• Zone 0 element super.!s!on adds secur!ty
to :uadr!lateral d!stance elements dur!ngpole-scatter operat!ng cond!t!ons !thout
sacr!$!c!ng dependa!l!ty
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!estions3