ABB RED650 Technical Manual page 265

1MRK 505 394-UEN A
Line differential protection RED650 2.2 IEC
Technical manual
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 ÷
>
è U ø
IECEQUATION2421 V1 EN-US
The customer programmable curve can be created as:
×
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
infinite. There will be an undesired discontinuity. Therefore a tuning parameter
CrvSatn is set to compensate for this phenomenon. In the voltage interval U
to U > · (1.0 + CrvSatn/100) the used voltage will be: U
n
If the programmable curve is used this parameter must be calculated so that:
CrvSatn
× - >
B C 0
100
EQUATION1440 V1 EN-US
The details of the different inverse time characteristics are shown in section
"Inverse characteristics".
TRIP signal issuing requires that the residual overvoltage condition continues for at
least the user set time delay. This time delay is set by the parameter t1 and t2 for
definite time mode (DT) and by some special voltage level dependent time curves
for the inverse time mode (IDMT).
If the START condition, with respect to the measured voltage ceases during the
delay time, and is not fulfilled again within a user defined reset time (tReset1 and
tReset2 for the definite time and tIReset1 and tIReset2 for the inverse time) the
corresponding START output is reset, after the defined reset time has elapsed.

0.035
2.0



+
0.035
+
D
p
Section 9
Voltage protection
(Equation 49)
(Equation 50)
(Equation 51)
> up
n
> · (1.0 + CrvSatn/100).
n
(Equation 52)
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