ABB RELION 620 Series Technical Manual page 706

Section 4
Protection functions
4.6
4.6.1
4.6.1.1
4.6.1.2
4.6.1.3
4.6.1.4
700
Frequency protection
Frequency protection FRPFRQ
Identification
Function description
Frequency protection
Function block
GUID-744529D8-E976-4AFD-AA77-85D6ED2C3B70 V1 EN
Figure 356: Function block
Functionality
The frequency protection function FRPFRQ is used to protect network components
against abnormal frequency conditions.
The function provides basic overfrequency, underfrequency and frequency rate-of-
change protection. Additionally, it is possible to use combined criteria to achieve even
more sophisticated protection schemes for the system.
The function contains a blocking functionality. It is possible to block function outputs,
timer or the function itself, if desired.
Operation principle
The function can be enabled and disabled with the Operation setting. The
corresponding parameter values are "On" and "Off".
The operation of FRPFRQ can be described using a module diagram. All the modules
in the diagram are explained in the next sections.
IEC 61850 IEC 60617
identification identification
FRPFRQ f>/f<,df/dt
1MRS757644 F
ANSI/IEEE C37.2
device number
81
620 series
Technical Manual