ABB REC650 - Identification; Functionality

6.4.1 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
6.4.2 Functionality
The four step residual overcurrent protection, zero or negative sequence direction
(EF4PTOC) has a settable inverse or definite time delay independent for step 1 and 4
separately. Step 2 and 3 are always definite time delayed.
All IEC and ANSI inverse time characteristics are available.
EF4PTOC can be set directional or non-directional independently for each of the
steps.
The directional part of the function can be set to operate on following combinations:
• Directional current (I3PDir) versus Polarizing voltage (U3PPol)
• Directional current (I3PDir) versus Polarizing current (I3PPol)
• Directional current (I3PDir) versus Dual polarizing (UPol+ZPol x IPol) where
ZPol = RPol + jXPol
IDir, UPol and IPol can be independently selected to be either zero sequence or
negative sequence.
Other setting combinations are possible, but not recommended.
Second harmonic blocking level can be set for the function and can be used to block
each step individually.
EF4PTOC can be used as main protection for phase-to-earth faults.
EF4PTOC can also be used to provide a system back-up for example, in the case of the
primary protection being out of service due to communication or voltage transformer
circuit failure.
Directional operation can be combined together with corresponding communication
logic in permissive or blocking teleprotection scheme. Current reversal and weak-end
infeed functionality are available as well.
1MRK 511 287-UEN A Section 6
Current protection
93
Technical manual