The pickup value (0.1 A or 0.05 A in the example) is set in address 2706 1Phase I>. The Ι>> stage is not
required (address 2703 1Phase I>> = ∞).
The trip command can be delayed under address 2707 T 1Phase I>. This time delay is usually set to 0.
If a higher number of current transformers is connected in parallel, e.g. when using as busbar protection with
several feeders, the magnetising currents of the transformers connected in parallel cannot be neglected
anymore. In this case, the sum total of the magnetising currents at half knee-point voltage (corresponding to
the setting value) has to be established. These magnetising currents reduce the current through the resistor R.
The actual pickup value thus increases accordingly.
Use as Tank Leakage Protection
If the single-phase time overcurrent protection is used as tank leakage protection, only the pickup value for
the respective 1-phase current input is set on 7UT6x.
The tank leakage protection is a highly sensitive overcurrent protection which detects the leakage current
between the isolated transformer tank and earth. Its sensitivity is set in address 2706 1Phase I>. Stage Ι>>
is not used (address 2703 1Phase I>> = ∞).
The trip command can be delayed in address 2707 T 1Phase I>. Normally, this delay time is set to 0.
NOTE
In the following parameter overview the addresses 2703 and 2706 apply to a high-sensitive current meas-
uring input and are independent from the rated current.
Settings
The table indicates region-specific presettings. Column C (configuration) indicates the corresponding secon-
dary nominal current of the current transformer.
Addr.
Parameter C Setting Options Default Setting Comments
2701 1Phase O/C OFF
ON
Block relay
OFF 1Phase Time Overcurrent
2702 1Phase I>> 1A 0.05 .. 35.00 A; ∞ 0.50 A 1Phase O/C I>> Pickup
5A 0.25 .. 175.00 A; ∞ 2.50 A
2703 1Phase I>> 0.003 .. 1.500 A; ∞ 0.300 A 1Phase O/C I>> Pickup
2704 T 1Phase I>> 0.00 .. 60.00 sec; ∞ 0.10 sec T 1Phase O/C I>> Time
Delay
2705 1Phase I> 1A 0.05 .. 35.00 A; ∞ 0.20 A 1Phase O/C I> Pickup
5A 0.25 .. 175.00 A; ∞ 1.00 A
2706 1Phase I> 0.003 .. 1.500 A; ∞ 0.100 A 1Phase O/C I> Pickup
2707 T 1Phase I> 0.00 .. 60.00 sec; ∞ 0.50 sec T 1Phase O/C I> Time Delay
Information List
No.
Information Type of
Informa-
tion
Comments
200.2404 >BLK 1Ph. O/C SP >BLOCK Time Overcurrent 1Phase
200.2411 O/C 1Ph. OFF OUT Time Overcurrent 1Phase is OFF
200.2412 O/C 1Ph. BLK OUT Time Overcurrent 1Phase is BLOCKED
200.2413 O/C 1Ph. ACT OUT Time Overcurrent 1Phase is ACTIVE
200.2421 O/C 1Ph PU OUT Time Overcurrent 1Phase picked up
2.7.5
2.7.6
Functions
2.7 Single-Phase Time Overcurrent Protection
SIPROTEC 4, 7UT6x, Manual 185
C53000-G1176-C230-5, Edition 09.2016
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