Non-Directional Earth-Fault Protection Efxptoc - ABB RELION 620 Series Technical Manual

Protection functions
4.2 Earth-fault protection
4.2.1

Non-directional earth-fault protection EFxPTOC

4.2.1.1 Identification
Function description
Non-directional earth-fault protec-
tion, low stage
Non-directional earth-fault protec-
tion, high stage
Non-directional earth-fault protec-
tion, instantaneous stage
4.2.1.2 Function block
Figure 186: Function block
4.2.1.3 Functionality
The non-directional earth-fault protection function EFxPTOC is used as non-
directional earth-fault protection for feeders.
The function starts and operates when the residual current exceeds the set limit.
The operate time characteristic for low stage EFLPTOC and high stage EFHPTOC
can be selected to be either definite time (DT) or inverse definite minimum
time (IDMT). The instantaneous stage EFIPTOC always operates with the DT
characteristic.
In the DT mode, the function operates after a predefined operate time and resets
when the fault current disappears. The IDMT mode provides current-dependent
timer characteristics.
The function contains a blocking functionality. It is possible to block function
outputs, timers or the function itself, if desired.
4.2.1.4 Operation principle
The function can be enabled and disabled with the
corresponding parameter values are "On" and "Off".
The operation of EFxPTOC can be described by using a module diagram. All the
modules in the diagram are explained in the next sections.
376
EFLPTOC
Io OPERATE
BLOCK START
ENA_MULT
IEC 61850
identification
EFLPTOC
EFHPTOC
EFIPTOC
EFHPTOC
Io OPERATE
BLOCK START
ENA_MULT
1MRS757644 H
IEC 60617 ANSI/IEEE C37.2
identification device number
Io> 51N-1
Io>> 51N-2
Io>>> 50N/51N
EFIPTOC
Io OPERATE
BLOCK START
ENA_MULT
Operation setting. The
Technical Manual
620 series