Function Block; Functionality; Operation Principle - ABB RELION 620 Series Technical Manual

1MAC504801-IB E
4.4.5.2
4.4.5.3
4.4.5.4
620 series ANSI
Technical Manual
Function description
Power factor

Function block

55
I_A TRIP
I_B PICKUP
I_C ALARM
V_A
V_B
V_C
DISABLE
BLOCK
GUID-C44ECC34-D5FE-4068-B168-6672A1EB2DDB V1 EN
Figure 169: Function block

Functionality

The under power factor function 55 is used to provide out-of-step and loss of, or under
excitation protection for small synchronous motors and generators. The function
calculates the power factor and uses a threshold of under power factor as an indication of
an out-of-step and/or loss of excitation condition.
In addition, the function can be applied as a power factor controller.
The function contains a blocking functionality. It is possible to block function outputs,
timers or the function itself, if desired.

Operation principle

The function can be enabled and disabled with the Operation setting. The corresponding
parameter values are "Enable" and "Disable".
The operation of 55 can be described using a module diagram. All the modules in the
diagram are explained in the next sections.
Protection functions
IEC 61850 IEC 60617
identification identification
MPUPF PF<
Section 4
ANSI/IEEE C37.2
device number
55
367