ABB Relion 620 Series - Page 329

Voltage level Effective start value (I> effective)
U < Voltage high limit Start value low
U ≥ Voltage high limit Start value
In this example, U represents the measured input voltage. This voltage step
characteristic is graphically represented in Figure 166 .
Figure 166: 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 Effective start value (I> effective)
U < Voltage low limit Start value low
U ≥ Voltage high limit Start value
If Voltage low limit ≤ U < Voltage high limit ,
I > (effective)=A -
A-I >
C - D
(C -U)






⋅






(Equation 8)
A
set Start value low
I> set Start value
C set Voltage high limit
D set Voltage low limit
1MRS757644 H Protection functions
620 series
Technical Manual
329