ABB RELION REX640 Technical Manual page 358

Section 4
Protection functions
352
GUID-9F99FB62-175A-4F95-BD24-3F1149ACC8AB V1 EN
Figure 199: Effective start value for voltage step characteristic
The voltage slope characteristic is achieved by assigning different values to Voltage
high limit and Voltage low limit. The effective start value calculation is based on the
equations.
Voltage level
U < Voltage low limit
Voltage high limit
U ≥
If Voltage low limit ≤ U < Voltage high limit,
A- I >


I > (effective)=A -


C - D


GUID-99A1565C-FA83-4B65-8EDA-537D1F0EF24F V1 EN
A is set Start value low
I> is set Start value
Voltage high limit
C is set
Voltage low limit
D is set
Here U represents the measured input voltage. The voltage slope characteristic is
graphically represented.
Effective start value (I> effective)
Start value low
Start value


(C -U)
 ⋅



1MRS759142 C
(Equation 27)
REX640
Technical Manual