ABB Relion 670 Series Product Manual page 17

Busbar protection REB670
Customized
Product version: 1.2
5. Current protection
Four step phase overcurrent protection OC4PTOC
The four step phase overcurrent protection function
OC4PTOC has an 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
together with an optional user defined time characteristic.
The directional function is voltage polarized with memory. The
function can be set to be directional or non-directional
independently for each of the steps.
Second harmonic blocking level can be set for the function
and can be used to block each step individually
This function can be used as a backup bay protection (e.g.
for transformers, reactors, shunt capacitors and tie-breakers).
A special application is to use this phase overcurrent
protection to detect short-circuits between the feeder circuit
breaker and feeder CT in a feeder bay when the circuit
breaker is open. This functionality is called end-fault
protection. In such case unnecessarily operation of the
busbar differential protection can be prevented and only fast
overcurrent trip signal can be sent to the remote line end. In
order to utilize this functionality the circuit breaker status and
CB closing command must be connected to the REB670.
One of the overcurrent steps can be set and configured to act
as end-fault protection in REB670.
Four step single phase overcurrent protection PH4SPTOC
Four step single phase overcurrent protection
(PH4SPTOC)has an inverse or definite time delay independent
for each step separately.
All IEC and ANSI time delayed characteristics are available
together with an optional user defined time characteristic.
The function is normally used as end fault protection to clear
faults between current transformer and circuit breaker.
Thermal overload protection, two time constant TRPTTR
If a power transformer or generator reaches very high
temperatures the equipment might be damaged. The
insulation within the transformer/generator will have forced
ageing. As a consequence of this the risk of internal phase-to-
phase or phase-to-earth faults will increase. High temperature
will degrade the quality of the transformer/generator insulation.
The thermal overload protection estimates the internal heat
content of the transformer/generator (temperature)
continuously. This estimation is made by using a thermal
model of the transformer/generator with two time constants,
which is based on current measurement.
Two warning levels are available. This enables actions in the
power system to be done before dangerous temperatures are
reached. If the temperature continues to increase to the trip
ABB
value, the protection initiates a trip of the protected
transformer/generator.
Breaker failure protection CCRBRF
Breaker failure protection (CCRBRF) ensures fast back-up
tripping of surrounding breakers in case the own breaker fails
to open. CCRBRF can be current based, contact based, or
an adaptive combination of these two conditions.
Current check with extremely short reset time is used as
check criterion to achieve high security against inadvertent
operation.
Contact check criteria can be used where the fault current
through the breaker is small.
CCRBRF can be single- or three-phase initiated to allow use
with single phase tripping applications. For the three-phase
version of CCRBRF the current criteria can be set to operate
only if two out of four for example, two phases or one phase
plus the residual current start. This gives a higher security to
the back-up trip command.
CCRBRF function can be programmed to give a single- or
three-phase re-trip of the own breaker to avoid unnecessary
tripping of surrounding breakers at an incorrect initiation due
to mistakes during testing.
Breaker failure protection, single phase version CCSRBRF
Breaker failure protection, single phase version (CCSRBRF)
function ensures fast back-up tripping of surrounding
breakers.
A current check with extremely short reset time is used as
check criteria to achieve a high security against unnecessary
operation.
CCSRBRF can be programmed to give a re-trip of the own
breaker to avoid unnecessary tripping of surrounding
breakers at an incorrect starting due to mistakes during
testing.
Directional over/underpower protection GOPPDOP/
GUPPDUP
The directional over-/under-power protection GOPPDOP/
GUPPDUP can be used wherever a high/low active, reactive
or apparent power protection or alarming is required. The
functions can alternatively be used to check the direction of
active or reactive power flow in the power system. There are
a number of applications where such functionality is needed.
Some of them are:
• detection of reversed active power flow
• detection of high reactive power flow
Each function has two steps with definite time delay. Reset
times for both steps can be set as well.
1MRK505273-BEN D
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