ABB RELION 670 SERIES Applications Manual page 456

Section 8
Impedance protection
450
= × ×
RFPP v tnPP 0.8
n z
EQUATION1538 V1 EN
×
V tnPG
= ×
RFPG Z 0.8
n
2
EQUATION1993-ANSI V1 EN
Here is factor 0.8
considered for safety
reasons and:
RFPG
phase-to-ground resistive reach setting for a power swing distance protection zone
n
n in Ω
RFPP
phase-to-phase resistive reach setting for a power swing distance protection zone
n
n in Ω
tnPG
time delay for phase-to-ground 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, 68)
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 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 O/C EF
s
s
Line distance protection REL670 2.2 ANSI
1MRK 506 369-UUS -
(Equation 422)
(Equation 423)
Application manual