ABB REL670 2.2 IEC Applications Manual page 427

1MRK 506 369-UEN B
Line distance protection REL670 2.2 IEC
Application manual
×
v tnPE
= ×
RFPE z
n
2
EQUATION1539 V1 EN-US
Here is factor 0.8
considered for safety
reasons and:
RFPE
phase-to-earth resistive reach setting for a power swing distance protection
n
zone n in Ω
RFPP
phase-to-phase resistive reach setting for a power swing distance protection
n
zone n in Ω
tnPE
time delay for phase-to-earth fault measurement of power swing distance
protection zone n in
tnPP
time delay for phase-to-phase fault measurement of power swing distance
protection zone n in
Time-delay for the overreaching power swing zone
Time delay for the overreaching power swing zone is not an important parameter, if
the zone is used only for the protection purposes at power-swings.
Consider the normal time grading, if the overreaching zone serves as a time
delayed back-up zone, which is not blocked by the operation of Power swing
detection (ZMRPSB) function.
Timers within the power swing logic
Settings of the timers within Power swing logic (PSLPSCH) depend to a great
extent on the settings of other time delayed elements within the complete
protection system. These settings differ within different power systems. The
recommended settings consider only the general system conditions and the most
used practice at different utilities. It is always necessary to check the local system
conditions.
The carrier send timer tCS is used for safety reasons within the logic. It requires
continuous presence of the input signal STPSD, before it can issue a carrier send
signal. A time delay between 50 and 100 ms is generally sufficient.
The trip timer tTrip is used for safety reasons within the logic. It requires
continuous presence of the input signal STPSD, before it can issue a tripping
command during the power swings. A time delay between 50 and 100 ms is
generally sufficient.
The blocking timer tBlkTr prolongs the presence of the BLKZMOR output signals,
which can be used to block the operation of the power swing zones after the
detected single-phase-to-earth faults during the power swings. It is necessary to
permit the O/C EF protection to eliminate the initial fault and still make possible
for the power swing zones to operate for possible consecutive faults. A time delay
between 150 and 300 ms is generally sufficient.
0.8
s
s
Section 8
Impedance protection
(Equation 423)
SEMOD131360-43 v2
SEMOD131360-47 v3
421