ABB 615 series Technical Manual page 266

Section 4
Protection functions
260
Voltage control mode
In the Voltage control mode, the Effective pickup value is calculated based on the
magnitude of input voltages V_AB, V_BC and V_CA. The voltage dependency is phase
sensitive, which means that the magnitude of one input voltage controls the pickup value
of only the corresponding phase, that is, the magnitude of voltage inputs V_AB, V_BC and
V_CA independently control the current pickup values of phases A, B and C.
Two voltage control characteristics, voltage step and voltage slope, can be achieved with
the Voltage high limit and Voltage low limit settings.
The voltage step characteristic is achieved when the Voltage high limit setting is equal to
the Voltage low limit setting. The effective pickup value is calculated based on the
equations.
Voltage level
V < Voltage high limit
Voltage high limit
V ≥
In this example, V represents the measured input voltage. This voltage step characteristic
is graphically represented in Figure.
Effective
pickup value
Pickup value
Pickup value low
Voltage high limit =
Voltage low limit
GUID-D4FB20C7-61E4-4BF0-9F3F-B86FE500FFAE V1 EN
Figure 128: Effective pickup value for voltage step characteristic
Effective pickup value (I> effective)
Pickup value low
Pickup value
V
1MAC059074-MB A
615 series ANSI
Technical Manual