ABB RELION 650 SERIES, Technical Manual

Page: 285 / 942

where:
Un> Set value for step 1 and step 2
U Measured voltage
The type B curve is described as:
2.0
480
0.035
32 0.5
n
n
k
t
U U
U

 
 
 
 
 

 
IECEQUATION2423 V2 EN-US
(Equation 45)
The type C curve is described as:
3.0
480
0.035
32 0.5
n
n
k
t
U U
U
×
= +
æ ö
- >
× -
ç ÷
>
è ø
IECEQUATION2425 V1 EN-US
(Equation 46)
The customer programmable curve is defined by the below equation, where A, B,
C, D, k and p are settings:
p
n
n
k A
t D
U U
B C
U
×
= +
æ ö
- >
× -
ç ÷
>
è ø
EQUATION1439 V2 EN-US
(Equation 47)
When the denominator in the expression is equal to zero the time delay will be
infinity. There will be an undesired discontinuity. Therefore, a tuning parameter
CrvSatn is set to compensate for this phenomenon. In the voltage interval Un> up
to Un> · (1.0 + CrvSatn /100) the used voltage will be: Un> · (1.0 + CrvSatn /100).
If the programmable curve is used this parameter must be calculated so that:
0
100
CrvSatn
B C
× - >
EQUATION1435 V1 EN-US
(Equation 48)
The highest phase (or phase-to-phase) voltage is always used for the inverse time
delay integration, see figure
136 . The details of the different inverse time
characteristics are shown in section "Inverse characteristics" .
1MRK 506 382-UEN A
Section 8
Voltage protection
Line distance protection REL650 2.2 IEC 279
Technical manual