ABB RED615 Product Manual page 28

Line Differential Protection and Control
RED615
Product version: 2.0
Protection functions
Table 24. Line differential protection (LNPLDF)
Characteristics
1)
Operation accuracy
High stage, operate time
Reset time
Reset ratio
Retardation time (Low stage)
Operate time accuracy in definite time mode
Operate time accuracy in inverse time mode
1) With the symmetrical communication channel (as when using dedicated fiber optic).
2) Without additional delay in the communication channel (as when using dedicated fiber optic).
3) Including the delay of the output contact. When differential current = 2 x High operate value and f
4) Low operate value multiples in range of 1.5 to 20.
28
Value
Depending on the frequency of the current
measured: f
Low stage
High stage
Minimum
22 ms
2)3)
< 40 ms
Typical 0.96
< 40 ms
±1.0% of the set value or ±20 ms
±5.0% of the set value or ±20 ms
1MRS756500 B
Issued: 03.07.2009
±2 Hz
n
±2.5% of the set value
±2.5% of the set value
Typical Maximum
25 ms 29 ms
4)
= 50 Hz.
n
ABB