Settings Of The 90% Stator Earth Fault Protection - Siemens Siprotec 7UM62 Manual

2.26.2.1 Settings of the 90% Stator Earth Fault Protection

Addr. Setting Title
5001 S/E/F PROT.
5002 U0>
5003 3I0>
5004 DIR. ANGLE
5005 T S/E/F
7UM62 Manual
C53000-G1176-C149-3
Voltage divider
Toroidal c.t.
Protected zone
With full neutral displacement voltage, the load resistor supplies:
500 V
-------------- -
10 Ω
Referred to the 6.3 kV side, this results in:
I
EE prim
The secondary current of the toroidal transformer supplies to the input of the device:
I
EE sec
For a protected zone of 90 %, the protection should already operate at 1/10 of the full
displacement voltage, whereby only 1/10 of the earth fault current is generated
In this example 3I0> is set to 11 mA. For the displacement voltage setting, 1/10 of the
full displacement voltage is used (because of the 90% protected zone). Considering a
voltage divider of 500 V/100 V, this results in:
Setting value U0> = 10 V
The time delay must lie below the 50 A capability time of the loading resistor, i.e. below
20 s. The overload capability of the earthing transformer must also be considered if it
lies below that of the loading resistor.
Setting Options
OFF
ON
Block relay for trip com-
mands
2.0..125.0 V
2..1000 mA
0..360 °
0.00..60.00 sec; ∞
90–%–Stator Earth Fault Protection (ANSI 59N, 64G, 67G)
500 V / 100 V
60 A/1 A
90 %
50 A
=
500 3 ⁄
⋅
50 A ----------------------------------- 3
=
6300 V
I
6.87 A
EE prim
------------------------ - ---------------- -
= =
⁄
60 A 1 A
115 mA
------------------- -
Setting 3I0>
=
10
Default Setting
OFF
10.0 V
5 mA
15 °
0.30 sec
⋅
6.87 A
=
⁄ ( )
3
= 115 mA
60
11.5 mA
=
Comments
Stator Earth Fault Protection
U0> Pickup
3I0> Pickup
Angle for Direction Determina-
tion
T S/E/F Time Delay
183