Four Step Residual Overcurrent Protection; Identification; Application - ABB RELION 670 Series Applications Manual

1MRK 504 152-UEN B
³
I m in
EQUATION287 V1 EN-US
Where:
I and I
fA
Considering the safety margins mentioned previously, the minimum setting (Is) is:
I = 1.3 × I
s
EQUATION288 V3 EN-US
Transformer inrush current shall be considered.
The setting of the protection is set as a percentage of the base current (
Operation : set the protection to On or Off .
IN>> : Set operate current in % of IBase .
StValMult : The operate current can be changed by activation of the binary input ENMULT to
the set factor
8.4 Four step residual overcurrent protection, (Zero
sequence or negative sequence directionality)
EF4PTOC
8.4.1

Identification

Function description
Four step residual overcurrent
protection
8.4.2

Application

The four step residual overcurrent protection EF4PTOC is used in several applications in the
power system. Some applications are:
• Earth-fault protection of feeders in effectively earthed distribution and subtransmission
systems. Normally these feeders have radial structure.
• Back-up earth-fault protection of transmission lines.
• Sensitive earth-fault protection of transmission lines. EF4PTOC can have better sensitivity
to detect resistive phase-to-earth-faults compared to distance protection.
• Back-up earth-fault protection of power transformers.
• Earth-fault protection of different kinds of equipment connected to the power system
such as shunt capacitor banks, shunt reactors and others.
Application manual
, ,
M A X I ( I I )
fA fB M
have been described for the single line case.
fB
min
StValMult .
IEC 61850 IEC 60617
identification identification
EF4PTOC
4(IN>)
4
alt
4
TEF-REVA V2 EN-US
Section 8
Current protection
(Equation 440)
(Equation 441)
IBase ).
ANSI/IEEE C37.2
device number
51N_67N
M12509-12 v9
IP14509-1 v6
M14881-1 v5
405