Overcurrent Protection (50/51 And 50Hs) - Siemens 7UT51 Instruction Manual

7UT51 v3
2.11

Overcurrent Protection (50/51 and 50HS)

Settings
Operational status
50HS Minimum current required for pickup
50HS Delay Time
50T Minimum current required for definite time pickup
50T Delay Time for definite time pickup
51 Minimum current required for inverse time pickup
51HS Delay Time for inverse time pickup
Pickup Threshold (approximate)
Reset Time Delay
Events that can control signal contacts, trip contacts, or
LEDs
Inherent Operating Times
50 and 50HS measuring time (when current is at two times
setting level, without parallel operation of other protection
functions)
51 Tripping Time Characteristics
Dropout time (50 and 50HS; approximate)
Overshot time (approximate)
Dropout Ratios
50/51 and 50HS dropout ratios (dropout/pickup;
approximate)
Operating Tolerances
50 and 50HS functions
50 and 50HS time delays
51 function
51 time delay
Effect of Environmental Influences on Times and Tolerances
Supply power voltage
Ambient temperature
System frequency for 50 and 50HS protection
System frequency for 51 protection
Table 2.8 Specifications for Overcurrent Protection (50/51 and 50HS) (details in Chapter 8)
PRIM-2330C
-
Active, inactive, or block contacts; choice can be temporarily
-
changed using binary signal inputs
0.10 to 30.00 times I n (0.01steps)
0.00 to 32.00 s, (0.01s steps) or ∞
0.10 to 30.00 times I n (0.01steps)
0.00 to 32.00 s, (0.01s steps) or ∞
0.10 to 20.00 times I n (0.01steps)
0.50 to 32.00 s, (0.01s steps) or ∞
1.1 times 51PU
0.00 to 60.00s (0.01s steps)
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 current at the time of a trip.
60 Hz
60 ms
see Section 8.4.2 see Section 8.4.2
on page 101 on page 101
75 ms
75 ms
0.95
±3% of setting value
greater of 10 ms or ±1% of setting value
pickup occurs when current between is 105% and 115% of
setting
greater of 30 ms or ±5% of setting value
≤ 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)
≤ 1.5% if between 98% and 102% of nominal frequency
≤ 2.5% if between 95% and 105% of nominal frequency
≤ 8% of theoretical time if system frequency between 95% and
105% of nominal frequency
Description of Relay
-
50 Hz 16 2/3 Hz
60 ms 150 ms
see Section 8.4.2
on page 101
75 ms 210 ms
75 ms 210 ms
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