ABB 615 Series - Operation Principle

The function contains a blocking functionality. It is possible to block function outputs,
timers or the function itself, if desired.
4.1.3.4 Operation principle
The function can be enabled and disabled with the Operation setting. The corresponding
parameter values are "Enable" and "Disable".
The operation of 51V can be described by using a module diagram. All the modules in the
diagram are explained in the next sections.
BLOCK
Timer
I_A
Level
detector
ENA_V_MULT
ENA_MULT
Effective
pickup
value
calculator
t
t
TRIP
PICKUP
V_AB
I_B
I_C
V_BC
V_CA
Blocking
logic
Phase
selection
logic
GUID-6216276B-61C3-498C-9E59-6ECB920E84D9 V1 EN
Figure 127: Functional module diagram
Effective pickup value calculator
The normal pickup current above which the overcurrent protection picks up is set through
the Pickup value setting. The Effective pickup value of the current may need to be changed
during certain conditions like magnetizing inrush or when the terminal voltages drop due
to a fault. Hence, the effective pickup value calculator module dynamically calculates the
effective pickup value above which the overcurrent protection picks up.
Four methods of calculating the effective pickup value are provided in 51V. These can be
chosen with the Control mode setting to be either "Voltage control", "Input control", "Volt
& Input Ctrl" or "No Volt dependency".
The calculated effective pickup value per phase, EFF_ST_VAL_A, EFF_ST_VAL_B,
EFF_ST_VAL_C, is available in the Monitored data view and is used by the Level
detector module.
All three phase-to-phase voltages should be available for the function to
operate properly.
1MAC059074-MB A Section 4
Protection functions
615 series ANSI 259
Technical Manual