ABB REL650 Technical Manual page 285

1MRK 506 382-UEN A
Line distance protection REL650 2.2 IEC
Technical manual
where:
Un> Set value for step 1 and step 2
U Measured voltage
The type B curve is described as:

k 480

t

 
U U
 
n

32 0.5

 U
n
IECEQUATION2423 V2 EN-US
The type C curve is described as:
×
k 480
=
t
3.0
æ ö
- >
U U
n
× -
32 0.5
ç ÷
>
U
è ø
n
IECEQUATION2425 V1 EN-US
The customer programmable curve is defined by the below equation, where A, B,
C, D, k and p are settings:
×
k A
=
t
æ ö
- >
U U
n
× -
B C
ç ÷
>
U
è ø
n
EQUATION1439 V2 EN-US
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:
CrvSatn
× - >
B C 0
100
EQUATION1435 V1 EN-US
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

0.035
2.0



+
0.035
+
D
p
"Inverse characteristics".
Section 8
Voltage protection
(Equation 45)
(Equation 46)
(Equation 47)
(Equation 48)
279