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VAMP 221
Arc protection system
Technical description
VAMP Ltd
24
VAMP 24h Technical Support: +358 (0)20 753 3264
VM221.EN013
3.2.1.
Functional system description
The protected object is medium voltage switchgear with two
separate inputs. The switchgear has a longitudinal busbar in a
bus-bar between the inputs.
To minimize the fault zone, the switchgear is divided into two
separate zones when structurally possible. The different zones
are limited by bus-coupler circuit breakers and monitored by
light sensitive elements (3 and 4). The system receives current
criteria from the central unit (1) and current I/O unit (26),
which have been installed on incomers.
Switchgear protection has been ensured by wiring the CBFP
contacts to the opposite side of the supply transformers. When
setting the CBFP delay time, the standard break-time of the
feeder circuit breaker of the actual switchgear must be taken
into account. This may be very long for old circuit breakers.
The central unit and I/O units serve as trip units. The central
unit (1) trips its own feeder circuit breaker in zone 1 faults
(tripping group 1) and serves as CBFP in zone 1 and 2 faults
(tripping groups 1 and 2), if the current limit is exceeded. The
arc sensor I/O units (3 and 4) trip the bus-coupler circuit
breaker between zones 1 and 4 in faults in their own zone. The
zone 2 current I/O unit (3) trips its own bus-coupler circuit
breaker.
Arc alarm is taken from the alarm relay of the central unit,
which activates in faults in all zones. System self-supervision
alarm is also taken from the central unit alarm relay.
3.2.2.
System components
The system configuration comprises the following components:
•
one (1) VAMP 221 central units
•
one (1) VAM 4C current I/O unit
•
two (2) VAM 10L current I/O units
•
sixteen (16) VA 1 DA light sensitive elements