ABB Relion 670 series - Blocking logic

6.12.2.2 Blocking logic
Figure 190 presents the logical circuits, which control the operation of the
underreaching zone (zone 1) at power swings, caused by the faults and their clearance
on the remote power lines.
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
Figure 190: Control of underreaching distance protection (Zone 1) at power swings
caused by the faults and their clearance on adjacent lines and other
system elements
The logic is disabled by a logical one on functional input BLOCK. It can start only if
the following conditions are simultaneously fulfilled:
• PUPSD functional input signal must be a logical zero. This means, that Power
swing detection (ZMRPSB, 68) function must not detect power swinging over the
protected power line.
• PUZMPSD functional input must be a logical one. This means that the impedance
must be detected within the external boundary of ZMRPSB (68) function.
• PUZMOR functional input must be a logical one. This means that the fault must
be detected by the overreaching distance protection zone, for example zone 2.
The PUZMURPS functional output, which can be used in complete terminal logic
instead of a normal distance protection zone 1, becomes active under the following
conditions:
Section 6 1MRK505222-UUS C
Impedance protection
358
Technical reference manual