Siemens siprotec 7SA6 User Manual

Functions
6-397SA6 Manual
C53000-G1176-C156-2
(address 1611) is set to below the minimum short-circuit current (approx. 10 %). This
also applies to the phase currents during earth faults or double earth faults.
In address
1630 1ph FAULTS you can choose whether a phase–to–earth loop shall
be selected in an earthed network during single–phase pickup without earth current
(I
E
–release). The setting 1ph FAULTS = phase-earth is useful if no or only little
earth current can flow via the measuring point in the event of earth faults. With
1ph
FAULTS
= phase to phase only the leading phase–phase loop is measured in
the event of a single–phase pick-up in the earthed network.
Two further general settings refer to the final times, i.e. the tripping times in a worst
case scenario for faults outside all distance zones. They should be set above the delay
times for distance zones providing a final back-up option (also see “Independent
ZonesZ1uptoZ5”inSection6.2.4.2).
The directional final time
DELAY FORW. PU (address 1602) only works with short cir-
cuits in forward (line) direction if there is no impedance within a distance zone after
pick-up.
The non-directional final time
DELAY NON-DIR. (address 1603)worksforallshort-
circuits if there is no impedance within a distance zone after pick-up.
U/I(/ϕ)Pickup The meaning of the settings can be seen from Figure 6-21. Iph> (section a, address
1611) is the minimum current as described in the previous section, Iph>> (section c)
is the overcurrent pick-up.
Figure 6-21 Parameters of U/I/ϕ pick-up
In most cases the angular dependence is not required. Then the voltage-dependent
sectionbisvalidwhichresultsinthecharacteristica-b-c.Whencontrollingwith
Uphe
in the addresses 1612 Uph-e (I>>) and 1613 Uph-e (I>) the voltages for
phase–to–earth are inserted to determine the voltage-dependent branch b; corre-
spondingly when using
Uphph the voltages for phase–to–phase are set in the ad-
dresses
1614 Uph-ph (I>>) and 1615 Uph-ph (I>). The relevant settings are
determined according to the “Pickup Mode” (see above).
The characteristic has to be set such that it is just below the minimum expected volt-
age at the maximum expected load current. If in doubt, check the pick-up conditions
in accordance with the U/I characteristic.
123
10
20
30
40
50
60
U
V
I
I
N
U(Iϕ>)
U(I>>)
U(I>)
Iph> Iϕ> Iph>>
Pick-up only
at ϕ>
Load Range
Pick-up Independent
from Angle
a
b
c
d
e

Siemens siprotec 7SA6 Specifications

General

Brand	Siemens
Model	siprotec 7SA6
Category	Relays
Language	English