End Fault in Bus Protection
Contr. Question 15 Pref. Subject 1
Jorge Cardenas (GE Multilin
Presented at the 2007 CIGRE-Madrid Conference
2007-PS1-15-ES01-Cardenas
End Fault Protection
Breakers: Bus-side CTs
CT
Blind spot for
bus protection
CB
• Blind spot exists between the CB and CT
• CB is going to be tripped by line protection
• After the CB gets opened, the current shall be removed from
differential calculations (expanding the differential zone up to
the opened CB)
• Relay configuration required: identical as for the Single-CT TieBreaker
2007-PS1-15-ES01-Cardenas
End Fault Protection
Breakers: Line-side CTs
CB
“Over-trip” spot for
bus protection
CT
• “Over-trip” spot between the CB and CT when the CB is opened
• When the CB gets opened, the current shall be removed from
differential calculations (contracting the differential zone up to
the opened CB)
• Relay configuration required: identical as for a Single-CT TieBreaker, but….
2007-PS1-15-ES01-Cardenas
End Fault Protection
Breakers: Line-side CTs
contract
CB
Blind spot for
bus protection
CT
• but….
• A blind spot created by contracting the bus differential zone
• End Fault Protection required to trip the remote end
2007-PS1-15-ES01-Cardenas