Functions
2.12 Ground Fault Protection 64, 67N(s), 50N(s), 51N(s)
SIPROTEC, 7SJ62/64, Manual
C53000-G1140-C207-2, Release date 01.2008
235
Table 2-15
Preferential Values of Standardized Currents for User-specific Tripping Curves
Figure 2-91
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
0
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 characteristic is
set to
V0/I0
ϕ
mea.
, the displacement voltage element is not relying on the current elements at all. Depend-
ing on the configuration at address
213
VT Connect. 3ph
, only the applicable limit value at address
3108
64-1 VGND
,
3109
64-1 VGND
or
3110
64-1 VGND
is accessible.
MofPU = 1 to 1.94
MofPU = 2 to 4.75
MofPU = 5 to 7.75
MofPU p = 8 to 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
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