ABB REC670 Applications Manual page 278

Section 12
System protection and control
272
æ
ç
A
[ ]
ç
= +
s
t
ç
p
æ ö
i
-
C
ç
ç ÷
>
è in ø
è
EQUATION13000031 V1 EN-US
In order to adapt to the previous relay characteristic the above equation can be re-
written in the following way:
æ
K
ç
ç I
[ ]
= +
s so T
t
ç
1
æ ö
I
ç
-
0
s
ç ÷
ç
I
è ø
è
so
EQUATION13000032 V1 EN-US
Thus if the following rules are followed when multi-purpose overcurrent stage one
is set:
•
in >
= I = 300A
S0
•
K 35566
= =
=
A
I 300
so
•
=
0.64
=
B T
01
•
C =
0.0
•
p =
1.0
•
k =
1.0
then exact replica of the existing relay will be achieved. The following table
summarizes all required settings for the multi-purpose function:
Setting Group1
Operation
CurrentInput
IBase
VoltageInput
UBase
OPerHarmRestr
I_2ndI_fund
BlkLevel2nd
EnRestrainCurr
RestrCurrInput
RestrCurrCoeff
Table continues on next page
ö
÷
÷
×
B k
÷
÷
ø
ö
÷
÷
×
1
÷
01
÷
÷
ø
118.55
On
MaxPh
1000
MaxPh
20.50
Off
20.0
5000
Off
PosSeq
0.00
1MRK 511 401-UEN A
(Equation 106)
(Equation 107)
Bay control REC670 2.2 IEC
Application manual