ABB REF615 L - Function Block

4.2.5.2 Function block
OPERATE
START
Io
HAEFPTOC
I_REF_RES
BLOCK
GUID-A27B40F5-1E7D-4880-BBC4-3B07B73E9067 V2 EN
Figure 173: Function block
4.2.5.3 HAEFPTOC functionality
The harmonics earth-fault protection HAEFPTOC is used instead of a traditional
earth-fault protection in networks where a fundamental frequency component of
the earth-fault current is low due to compensation.
By default, HAEFPTOC is used as a standalone mode. Substation-wide application
can be achieved using horizontal communication where the detection of a faulty
feeder is done by comparing the harmonics earth-fault current measurements.
The function starts when the harmonics content of the earth-fault current exceeds
the set limit. The operation time characteristic is either definite time (DT) or
inverse definite minimum time (IDMT). If the horizontal communication is used
for the exchange of current values between the IEDs, the function operates
according to the DT characteristic.
The function contains a blocking functionality. It is possible to block function
outputs, timer or the function itself, if desired.
4.2.5.4 Operation principle
The function can be enabled and disabled with the Operation setting. The
corresponding parameter values are "On" and "Off".
The operation of the harmonics earth-fault protection can be described using a
module diagram. All the modules in the diagram are explained in the next sections.
1YHT530004D05 D Section 4
Protection functions
615 series 337
Technical Manual