ABB Relion 670 series, Technical Manual

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t
TD
V Vpickup
Vpickup
=
⋅
⋅
− >
>
−
+
480
32 0 5
0 035
.
.
ANSIEQUATION2287 V3 EN-US
(Equation 177)
The type C curve is described as:
t
TD
V Vpickup
Vpickup
=
⋅
⋅
− >
>
−
+
480
32 0 5
0 035
.
.
ANSIEQUATION2288 V2 EN-US
(Equation 178)
The customer programmable curve is defined by the below equation, where A, B, C, D, k and p are
settings:
P
TD A
t D
V Vpickup
B C
Vpickup
×
= +
-
× -
æ ö
ç ÷
è ø
EQUATION1616 V1 EN-US
(Equation 179)
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 Vpickup up to Vpickup · (1.0 +
CrvSatn/100) the used voltage
will be: Vpickup · (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 180)
The highest phase (or phase-to-phase) voltage is always used for the inverse time delay
integration, see figure 332 . The details of the different inverse time characteristics are shown in
section "Inverse characteristics" .
Section 9 1MRK 502 066-UUS B
Voltage protection
618
Technical manual