Siemens siprotec 7SA522 User Manual

2.3 Power swing detection (optional)
113
7SA522 Manual
C53000-G1176-C155-3
It is possible with FNo. 4160 ´!3RZ6ZLQJ%/.µ to block the power swing detec-
tion via a binary input.
Power Swing Trip-
ping
If tripping in the event of an unstable power swing (out-of-step condition) is desired,
the parameter 3RZHU6ZLQJWULS = <(6 is set. If the criteria for power swing detec-
tion are satisfied, the distance protection is initially blocked according to the configured
program for power swing blocking, to avoid tripping by the distance protection.
When the impedance vectors identified by the power swing detection exit the power
swing characteristic PPOL, the sign of the R components in the vectors are checked
to see if they are the same on exiting and entering the pickup polygon. If this is the
case, the power swing process is inclined to stabilize. Otherwise, the vector passed
through the power swing characteristic (loss of synchronism, case (4) in Figure2-36).
Stable power transmission is then no longer possible. The device outputs an alarm to
that effect (FNo 4163 ´36ZLQJXQVWDEµ), provided that the parameter at address
 3RZHU6ZLQJWULS is set to 12. The alarm FNo 4163 ´36ZLQJXQVWDEµ
is a pulse with a duration of approx. 50 ms, which can also be processed further via
output relay, e.g. for a cycle counter or a pulse counter.
Once instability is detected, the device issues a three-pole trip command, thereby iso-
lating the two system segments from each other. Power swing tripping is alarmed.
As the operating range of the power swing supplement depends on the distance pro-
tection settings, the power swing tripping
can only be active when the distance protec-
tion has been activated.
2.3.2 Setting Notes
The power swing supplement is only active if it has been set to 3RZHU6ZLQJ =
(QDEOHG (address ) during the configuration. For 3RZHU6ZLQJ no other param-
eters have to be set.
The four possible programs may be set in address  362SPRGH, as de-
scribed in Subsection 2.3: $OO]RQHVEORFN, ==%EORFN, =WR=EORFN
or ==%=EORFN.
Additionally the tripping function for unstable oscillations (out-of-step condition, loss of
system synchronism) can be set with parameter 3RZHU6ZLQJWULS (address ),
which should be set to <(6 if required (presetting is 12). In the event of power swing
tripping
it is recommended to set 362SPRGH = $OO]RQHVEORFN for the power
swing blocking
, to avoid premature tripping by the distance protection.
The tripping delay at least effective and following a power swing blocking can be set
at address  7ULS'(/$<36.

Siemens siprotec 7SA522 Specifications

General

Brand	Siemens
Model	siprotec 7SA522
Category	Protection Device
Language	English