EQUATION1538 V1 EN-US (Equation 391)
EQUATION1993-ANSI V1 EN-US (Equation 392)
Here is factor 0.8
considered for safety
reasons and:
RFPG
n
phase-to-ground resistive reach setting for a power swing distance protection
zone n in Ω
RFPP
n
phase-to-phase resistive reach setting for a power swing distance protection
zone n in Ω
tnPG
time delay for phase-to-ground fault measurement of power swing distance
protection zone n in
s
tnPP
time delay for phase-to-phase fault measurement of power swing distance
protection zone n in
s
Time-delay for the overreaching power swing zone
SEMOD131360-43 v2
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, 68) function.
Timers within the power swing logic
SEMOD131360-47 v3
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 PUPSD, 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 PUPSD, 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-ground faults during the power swings. It is necessary to permit the
Section 8 1MRK 504 163-UUS A
Impedance protection
464 Transformer protection RET670 2.2 ANSI
Application manual
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