51LR
Locked rotor
(definite time
characteristic)
IMn = 0.200 ... 2.000 In (motor current)
Is = 1.000 ... 20.000 IMn (start value)
t = 40 ... 30 000 ms
66
Number of starts
n (warm) = 1 ...10 (number of warm starts)
n (cold) = 1 ...10 (number of cold starts)
t = 1.00 .. 7200.00 s
T (warm) = 20 ... 200 °C (warm start temp. thereshold)
46
Unbalance load
Is = 0.05 ... 0.30 In (start value of the negative phase
sequence)
K = 0.5 ... 30.0
t Reset = 0 ... 2000 s
Timer decreasing rate = 0
…
100%
37
Low load
Pn = 50 ... 1000 000 kW (primary values)
Minimal load P = 5 ... 100% Pn
Minimal current I = 2 ... 20 % In
Operation time = 1.0 ... 1000.0 s
Differential protection functions
87
Differential
Differential
Transformer group = 0 ... 11
Transformer earthing = primary and or secondary side
Primary nominal current = 10.00 ... 100 000.00 A (prim
value)
Secondary nominal current = 10.00 ... 100 000.00 A (prim
value)
Threshold current = 0.10 ... 0.50 Ir (p.u.)
Unbiased region limit = 0.50
…
5.00 Ir (p.u.)
Slightly biased region threshold = 0.20 ... 2.00 Ir (p.u.)
Slightly biased region limit = 1.00 ... 10.0 Ir (p.u.)
Slope = 0.40 ... 1.00
Trip by Id> = 5.00 ... 40.00 In
Blocking by 2nd harmonic = 0.10
…
0.30 In
Blocking by 5th harmonic = 0.10
…
0.30 In
87N
Restricted earth
fault protection
(restricted
differential)
Reference nominal current = 1.00 ... 100000.00 A
Unbiased region threshold = 0.05 ... 0.50 Ir
Unbiased region limit = 0.01 ... 1.00 Ir
Slightly biased region slope = 0.01 ... 2.00
Slightly biased region limit = 0.01 ... 2.00 Ir
Heavily biased region slope = 0.10 ... 1.00
Relay operate angle = 60 ... 180°
t = 0.04 ... 100.00 s
Frequency protection function
81
Frequency
protection
Start value = 40.00 ... 75.00 Hz
Frequency gradient = 0.01 ... 1.00 Hz/s
t = 0.10 ... 30.00 s
U< = 0.10 ... 1.00 Un
Trip logic = freq. only / freq. AND freq. gradient / freq. OR
freq. gradient
Frequency supervision
Frequency
supervision
Start value = 0.04 ... 5.00 Hz
Time = 1.00 ... 300.00 s
Distance protection function
42
REF 542plus
REF 542plus
Multifunction Protection and Switchbay Control
Unit
Technical Reference Manual
1MRS755859