ABB REX 521 Technical Reference Manual, Standard Configurations

1MRS751802-MUM
REX 521
91
Protection Relay
Technical Reference Manual, Standard Configurations
Directional earth fault protection, low-set stage, Io>->
Start current
Start voltage
Operate time in DT mode
Time multiplier in IDMT mode
Operation mode
Operation criteria
Operation direction
Basic angle ϕ
b
Operation characteristic
Intermittent E/F
Measuring mode
Drop-off time of the operate time counter
1.0…25.0% of In
2.0…100.0% of Un
0.1…300.0 s
0.05…1.00
Not in use
Definite time
Extremely inverse
Very inverse
Normal inverse
Long time inverse
Basic angle & Uo
Basic angle
IoSin/Cos & Uo
IoSin/Cos
Non-directional Io
Non-directional Uo
Forward
Reverse
-90°... 0°
IoSin(ϕ)
IoCos(ϕ)
Not active
Active
Peak-to-peak
Fundamental frequency
0...1000 ms
Note! The values below apply when f/fn = 0.95...1.05
Operation accuracy
Start time
Reset time
Reset ratio, typically
Retardation time
Operate time accuracy in DT mode
Accuracy class index E in IDMT mode
±2.5% of set value + 0.0005 x In
±2.5% of set value or + 0.01 x Un
Phase angle ±2°
Injected neutral current > 2.0 x start current and
residual voltage > 2.0 x start voltage:
internal time < 72 ms
total time < 80 ms
40...1000 ms (depends on the minimum pulse width set
for the trip output)
0.95
< 50 ms
±2% of set value or ±20 ms
Class index E = 5.0 or ±20 ms

ABB REX 521 Specifications

General

Brand	ABB
Model	REX 521
Category	Other
Language	English