ABB RELION RET670, Applications Manual

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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.
8.15.3.2 Blocking and tripping logic for evolving power swings
SEMOD131360-55 v3
The second part of a complete Power swing logic (PSLPSCH) functionality is a
blocking and tripping logic for evolving power swings, see figure
230 and figure 231 .
The simplified logic is presented in figure 233 . The logic controls the operation of the
underreaching distance protection zone (Zone 1) at power swings, caused by the faults
and their clearance on the adjacent power lines. The logic should generally be
configured between distance protection zones 1 and 2.
Configuration
SEMOD131360-60 v2
The fault impedance should be detected within the external boundary of Power Swing
Detection (ZMRPSB, 68) function without power swing detected during the entire
fault duration. Configure for this reason the PUZMPSD to the functional output signal
of ZMRPSB (68) function, which indicates the measured impedance within its external
boundaries.
PUZMUR
BLOCK
AND
PUZMOR
PUZMPSD
PUPSD
0-tDZ
0-tZL
AND
OR
AND
AND
AND
-loop
OR
PUZMURPS
BLKZMOR
AND
en06000237_ansi.vsd
0
0
ANSI06000237 V1 EN-US
Figure 233: Blocking and tripping logic for evolving power swings
No system oscillation should be detected in power system. Configure for this reason
the PUPSD functional input to the PICKUP functional output of ZMRPSB (68)
function or to any binary input signal indicating the detected oscillations within the
power system.
1MRK 504 163-UUS A
Section 8
Impedance protection
Transformer protection RET670 2.2 ANSI 465
Application manual