ABB RELION 620 Series Technical Manual page 447

1MRS757644 F
4.2.5
4.2.5.1
4.2.5.2
4.2.5.3
4.2.5.4
620 series
Technical Manual
Rotor earth-fault protection MREFPTOC
Identification
Function description
Rotor earth-fault protection
Function block
GUID-9547375B-008F-4829-897A-5045ED3A922B V1 EN
Figure 220: Function block
Functionality
The rotor earth-fault protection function MREFPTOC is used to detect an earth fault
in the rotor circuit of synchronous machines. MREFPTOC is used with the injection
device REK510, which requires a secured 58, 100 or 230 V AC 50/60 Hz input source
and injects a 100 V AC voltage via its coupling capacitors to the rotor circuit towards
earth.
MREFPTOC consists of independent alarm and operating stages. The operating time
characteristic is according to definite time (DT) for both stages.
Operation principle
The function can be enabled and disabled with the Operation setting. The
corresponding parameter values are "On" and "Off".
The operation of MREFPTOC 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
MREFPTOC Io>R
Section 4
ANSI/IEEE C37.2
device number
64R
441