ABB REL650 - Four Step Residual Overcurrent Protection, Zero, Negative Sequence Direction EF4 PTOC (51 N;67 N)

m1.3.Is inI ³
EQUATION288 V2 EN (Equation 119)
Transformer inrush current shall be considered.
The setting of the protection is set as a percentage of the base current (IBase).
Operation: set the protection to Enabled or Disabled.
Pickup: Set operate current in % of IBase. IBase is a global parameter valid for all
functions in the IED.
7.6 Four step residual overcurrent protection, zero,
negative sequence direction EF4PTOC (51N/67N)
7.6.1 Identification
Function description IEC 61850
identification
IEC 60617
identification
ANSI/IEEE C37.2
device number
Four step residual overcurrent
protection, zero or negative sequence
direction
EF4PTOC
2
IEC11000263 V1 EN
51N/67N
7.6.2 Application
The four step residual overcurrent protection, zero or negative sequence direction
EF4PTOC (51N_67N) is used in several applications in the power system. Some
applications are:
• Ground-fault protection of feeders in effectively grounded distribution systems.
Normally these feeders have radial structure.
• Back-up ground-fault protection of subtransmission and transmission lines.
• Sensitive ground-fault protection of transmission lines. EF4PTOC (51N_67N) can
have better sensitivity to detect resistive phase-to-ground-faults compared to distance
protection.
• Back-up ground-fault protection of power transformers with ground source at
substation.
Section 7 1MRK 506 334-UUS A
Current protection
202
Application manual