ABB Relion 620 Series - Page 701

4.6.1.1 Identification
Function description IEC 61850
identification
IEC 60617
identification
ANSI/IEEE C37.2
device number
Frequency protection FRPFRQ f>/f<,df/dt 81
4.6.1.2 Function block
Figure 366: Function block
4.6.1.3 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.
4.6.1.4 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.
1MRS757644 H
Protection functions
620 series
Technical Manual
701