Ground Differential Protection (87N) (Optional With 7Ut513) - Siemens 7UT51 Instruction Manual

2
Description of Relay
2.10 Ground Differential Protection (87N) (Optional with
7UT513)
Settings
Operational status
Minimum differential current required for pickup (87N)
The critical limit angle that determines the restraint of the
protection (corresponding value of k)
Inrush restraint based on 2nd harmonic current
Time delay before trip
Time delay before reset
Events that can control signal contacts, trip contacts, or
LEDs
Inherent Operating Times
-
Pickup time with single ended infeed:
≥ 1.5 times 87N pickup threshold level (approx.)
I
DIFF
≥ 5.0 times 87N pickup threshold level (approx.)
I
DIFF
Dropout (approximate)
Dropout Ratio
87N dropout ratio (dropout/pickup; approximate)
Operating Tolerances (with default settings)
Pickup characteristic
Set time delays
Effect of Environmental Influences on Times and Tolerances
Supply power voltage
Ambient temperature
System frequency
Table 2.7 Specifications for Ground Differential Protection (87N) (details in Chapter 7)
24
-
Active, inactive, or block contacts; choice can be temporarily
-
changed using binary signal inputs
0.05 to 2.00 times I (step 0.01)
n
130° ( k ≈1), 120° ( k ≈1.4), 110° ( k ≈2), 100° ( k ≈4), 90° ( k →∞),
10% to 80% of fundamental current (step 1%); restraint is
released when the differential current exceeds a set value
(1.0 to 20.0 times I , step 0.1).
n
0.00 to 60.00 s (step 0.01 s), or ∞
0.00 to 60.00 s (step 0.01 s)
Change in operational status; pickup, dropout, trip, and reset
events, start of time delay before trip. All events are logged, as
are the amplitude of the ground current and the phase
difference at the time of a trip.
60 Hz
25 ms
17 ms
25 ms
0.7
±5% of characteristic value (for I < 5× I
±1% of setting value or 10 ms, whichever is greater
≤ 1% if between 80% and 115% of nominal voltage
≤ 0.5% / 10 K if between 0°C and 40°C (32°F and 104°F)
≤ 1% if between 80% and 120% of nominal frequency
7UT51 v3
-
-
50 Hz 16 2/3 Hz
25 ms 75 ms
17 ms 25 ms
30 ms 90 ms
)
n
PRIM-2330C
angle