Siemens SIPROTEC 7UM62, Manual

Page: 162 / 602

Functions
146
7UM62 Manual
C53000-G1176-C149-3
Number of Power
Swings Address
3509 REP. CHAR. 1
determines the number of out-of-step periods for
characteristic 1 which will lead to trip, i.e.the number of times this characteristic must
have been passed through. For characteristic 1, 1 or 2 passes are normally adequate
as out-of-step conditions with the electrical centre within the power station unit should
not be tolerated too long, and the power swing frequency tends to accelerate during
an out-of-step condition, so that the electrical and dynamic stress of the machine
increases. On the other hand, for out-of-step conditions with the electrical centre being
in the network system a higher number of slip periods can be tolerated, so that
address
3510 REP. CHAR. 2
can usually be set to 4.
Each time characteristic 1 or 2 is passed through, a holding time set at address
3511
T-HOLDING
) is started. A detected out-of-step condition is maintained for that time so
that the counter is incremented with the next passing through. When no renewed
pickup occurs within this time, the counters n
1
or n
2
respectively are reset, i.e. the out-
of-step condition is “forgotten”. This time should be set higher that the longest
expected slip period (i.e. lowest slip frequency). Settings between 20 s and 30 s are
good values.
Each time one of the counters n
1
or n
2
is incremented, the holding time is restarted,
and an annunciation “Out-of-step characteristic 1" or “Out-of-step characteristic 2" is
issued. These annunciations disappear after the time which is set at address
3512 T-
SIGNAL
. If this time is set higher that the time between two power swings, the
annunciation “Out-of-step characteristic 1(2)” begins with the first out-of-step
detection and ends after the last detected out-of-step detection, prolonged wit the set
time
T-SIGNAL
.
2.18.2.1 Settings of the Out-of-Step Protection
With a rated secondary current of I
N
= 5 A, the parameters with the addresses 3504
to 3507 must be divided by 5.
Addr. Setting Title Setting Options Default Setting Comments
3501 OUT-OF-STEP OFF
ON
Block relay for trip com-
mands OFF Out-of-Step Protection
3502 I1> RELEASE 20.0..400.0 % 120.0 % Pickup Current for Measuring
Release I1>
3503 I2< RELEASE 5.0..100.0 % 20.0 % Pickup Current for Measuring
Release I2<
3504 Za 0.20..130.00 Ohm 4.50 Ohm Resistance Za of the Polygon
(width)
3505 Zb 0.10..130.00 Ohm 12.00 Ohm Reactance Zb of the Polygon
(reverse)
3506 Zc 0.10..130.00 Ohm 3.60 Ohm Reactance Zc of Polygon (for-
ward char.1)
3507 Zd - Zc 0.00..130.00 Ohm 6.40 Ohm Reactance Dif. Char.1 - Char.2
(forward)
3508 PHI POLYGON 60.0..90.0
°
90.0
°
Angle of Inclination of the Poly-
gon
3509 REP. CHAR. 1 1..4 1 Number of Power Swing: Cha-
racteristic 1