ABB RELION REX640 Technical Manual page 993

1MRS759142 C
REX640
Technical Manual
compartments of the switchgear, for example, in the busbar compartment, the circuit
breaker compartments, the bus riser and the outgoing feeder cable end compartments.
The light detected by the lens sensor inputs is compared to an automatically adjusted
reference level. Each light sensor input has its own reference level. When the light
exceeds the reference level of one of the inputs, the light is detected locally. When the
light has been detected locally or remotely and, depending on the operation mode, if
one or several phase currents exceed the set Phase start value limit, or the earth-fault
current the set Ground start value limit, the arc protection stage generates an operation
signal. The stage is reset in 30 ms, after all three-phase currents and the earth-fault
current have fallen below the set current limits.
The light signal output from an arc protection stage ARC_FLT_DET is activated
immediately in the detection of light in all situations. A station-wide arc protection is
realized by routing the light signal outputs to output contacts connected via physical
wires to the binary inputs of other relays, or by routing the light signal outputs through
the communication (IEC 61850/GOOSE signaling) to the virtual inputs of other
relays.
It is possible to block the tripping and the light signal output of the arc protection stage
with a binary input or a signal from another function block.
Arc protection with one protection relay
In installations, with limited possibilities to realize signaling between protection
relays protecting incoming and outgoing feeders, or if only the protection relay for the
incoming feeder is to be exchanged, an arc protection with a less selective level can be
achieved with one protection relay. In arc detection, the arc protection stage trips the
circuit breaker of the incoming feeder. The maximum recommended installation
distance between the two lens sensors in the busbar area is six meters and the
maximum distance from a lens sensor to the end of the busbar is three meters.
Section 4
Protection functions
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