Table 2-15
Preferential Values of Standardized Currents for User-specific Tripping Curves
MofPU = 1 bis 1.94
MofPU = 2 bis 4.75
MofPU = 5 bis 7.75
MofPU = 8 bis 20
1.00
1.50
2.00
3.50
5.00
6.50
8.00
15.00
1.06
1.56
2.25
3.75
5.25
6.75
9.00
16.00
1.13
1.63
2.50
4.00
5.50
7.00
10.00
17.00
1.19
1.69
2.75
4.25
5.75
7.25
11.00
18.00
1.25
1.75
3.00
4.50
6.00
7.50
12.00
19.00
1.31
1.81
3.25
4.75
6.25
7.75
13.00
20.00
1.38
1.88
14.00
1.44
1.94
[verwendung-einer-anwenderspezifizierbaren-kennlinie-260602-kn, 1, en_US]
Figure 2-96
Use of a user-defined characteristic
Determination of Ground-Faulted Phase
The ground-faulted phase may be identified in an ungrounded or resonant-grounded system, if the device is
supplied by three voltage transformers connected in a grounded-wye configuration. The phase in which the
voltage lies below setting
VPH MIN
at address 3106 is identified as the faulty phase as long as the other two
phase voltages simultaneously exceed the setting
VPH MAX
at address 3107. The setting
VPH MIN
must be
set less than the minimum expected operational phase-to-ground voltage. A typical setting for this address
would be 40 V. Setting
VPH MAX
must be greater than the maximum expected operational phase-to-ground
voltage, but less than the minimum expected operational phase-to-phase voltage. For V
Nom
= 100 V, approxi-
mately 75 V is a typical setting. These settings have no significance in a grounded system.
Displacement Voltage Element V
o
The displacement voltage
64-1 VGND
(address 3108 or 3109) or
64-1 VGND
(address 3110) is used to pick
up ground fault detection. At the same time, pickup of the voltage element is a condition for initiation of
direction determination (when setting the direction characteristic to
cos φ / sin φ
). If the direction char-
acteristic is set to
V0/I0 φ mea.
, the displacement voltage element is not relying on the current elements at
all. Depending on the configuration at address 213
VT Connect. 3ph
, only the applicable limit value at
address 3108 or 3109
64-1 VGND
or 3110
64-1 VGND
is accessible.
If two phase-to-phase voltages and the displacement voltage V
0
are supplied to the device, the measured
displacement voltage is used directly for ground fault recognition. The threshold for V
0
is set at address 3108
(7SJ64) or 3109 (7SJ62)
64-1 VGND
, where a more sensitive setting can be made than with a calculated
displacement voltage.
The upper setting threshold for 7SJ64 is higher than for 7SJ62 (see Technical Data).
Functions
2.13 Ground Fault Protection 64, 67N(s), 50N(s), 51N(s)
216
SIPROTEC 4, 7SJ62/64, Manual
C53000-G1140-C207-8, Edition 08.2016
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