Stub Protection Stbptoc; Identification; Application - ABB Relion REC670 Applications Manual

Section 7
Current protection
when gas pressure is low in a SF6 circuit breaker, of others. After the set time an alarm is
given, so that actions can be done to repair the circuit breaker. The time delay for back-up trip
is bypassed when the CBFLT is active. Typical setting is 2.0 seconds.
tPulse : Trip pulse duration. This setting must be larger than the critical impulse time of circuit
breakers to be tripped from the breaker failure protection. Typical setting is 200 ms.
7.10

Stub protection STBPTOC

7.10.1

Identification

Function description
Stub protection
7.10.2

Application

In a 1½-breaker switchyard the line protection and the busbar protection normally have
overlap when a connected object is in service. When an object is taken out of service it is
normally required to keep the diagonal of the 1½-breaker switchyard in operation. This is done
by opening the disconnector to the protected object. This will, however, disable the normal
object protection (for example the distance protection) of the energized part between the
circuit breakers and the open disconnector.
Stub protection STBPTOC is a simple phase overcurrent protection, fed from the two current
transformer groups feeding the object taken out of service. The stub protection is only
activated when the disconnector of the object is open. STBPTOCenables fast fault clearance of
faults at the section between the CTs and the open disconnector.
150
IEC 61850 IEC 60617
identification identification
STBPTOC
3I>STUB
SYMBOL-T V1 EN-US
1MRK 511 358-UEN A
ANSI/IEEE C37.2
device number
50STB
Application manual
IP14515-1 v3
M17108-1 v2
M12904-3 v5