Frequency Protection - ABB 615 series Technical Manual

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
678

Frequency protection

Frequency protection 81
Identification
Function description
Frequency protection
Function block
81
F TRIP
dF/dt OPR_UFRQ
OPR_OFRQ
BLOCK
OPR_FRG
PICKUP
ST_UFRQ
ST_OFRQ
ST_FRG
GUID-F876D957-3C2B-4E50-9E51-A969FB290FEB V1 EN
Figure 338: Function block
Functionality
The frequency protection function 81 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 "Enable" and "Disable".
The operation of 81 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
1MAC059074-MB A
ANSI/IEEE C37.2
device number
81
615 series ANSI
Technical Manual