ABB Relion REC670, Applications Manual

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In simple words this means that the CB is not breaking the current at the first zero
crossing after separation of the CB contacts. Instead current is re-ignited and only
braked at consecutive current zero crossings. This condition is manifested as high
current pulses at the moment of current re-ignition.
To detect this CB condition, the built in overcurrent feature can be used. Simply, any
start of the overcurrent feature during breaker normal opening means a restrike.
Therefore simple logic can be created in the Application Configuration tool to detect
such CB behavior. Such CB condition can be just alarmed, and if required, the built in
disturbance recorder can also be triggered.
To create this logic, a binary signal that the CB is going to be opened (but not trip
command) shall be made available to the IED.
8.16 Voltage-restrained time overcurrent protection
VRPVOC (51V)
GUID-613620B1-4092-4FB6-901D-6810CDD5C615 v4
8.16.1 Identification
GUID-7835D582-3FF4-4587-81CE-3B40D543E287 v4
Function description IEC 61850
identification
IEC 60617
identification
ANSI/IEEE C37.2
device number
Voltage-restrained time overcurrent
protection
VRPVOC I>/U< 51V
8.16.2 Application
GUID-622CDDDD-6D03-430E-A82D-861A4CBE067C v7
A breakdown of the insulation between phase conductors or a phase conductor and
ground results in a short-circuit or a ground fault. Such faults can result in large fault
currents and may cause severe damage to the power system primary equipment.
A typical application of the voltage-restrained time overcurrent protection is in the
generator protection system, where it is used as backup protection. If a phase-to-phase
fault affects a generator, the fault current amplitude is a function of time, and it
depends on generator characteristic (reactances and time constants), its load conditions
(immediately before the fault) and excitation system performance and characteristic.
So the fault current amplitude may decay with time. A voltage-restrained overcurrent
relay can be set in order to remain in the picked-up state in spite of the current decay,
and perform a backup trip in case of failure of the main protection.
The IED can be provided with a voltage-restrained time overcurrent protection
(VRPVOC, 51V). The VRPVOC (51V) function is always connected to three-phase
1MRK 511 401-UUS A
Section 8
Current protection
Bay control REC670 2.2 ANSI 235
Application manual