OLTC & OBCB
Protectors
 On
Load Tap Changers and Oil
Bushing Cable Boxes Explosion and
Fire Prevention
In
addition to the tank, protecting the
On Load Tap Changers and the Oil
Bushing Cable Boxes with the Transformer
Protector™ is
strongly recommended. For that purpose,
a Depressurization Set and a specific
Explosive Gas Elimination Set are used.
Protecting all transformer
oil capacities prevents the short-circuit
from damaging
the On Load Tap Changer or the Oil
Bushing Cable Box, and spreading
the fire to the transformer itself
as well
as to the whole power plant or substation.
For a minor additional price, the
Transformer Protector offers a complete
fire and
explosion prevention system for the
transformer.
Examples exist where as little as
200 liters (53 gallons) of burning
oil
from the OLTC have destroyed a complete
substation.
When not connected
to the Transformer Protector, OLTCs
can prevent
overpressure with a diaphragm or
a Pressure Relief Valve, which
are not
calibrated and do not allow oil
channeling
during an explosion. In fact, during
short-circuits, the OLTC cover
is very often forced off and burning
oil then
spreads onto the transformer, floor
and surrounding equipment, allowing
a fire to expand to the whole plant.
Short-circuit
consequences are more severe when
transformers are located
underground, inside industrial plants
with high explosion risks or in sensitive
environmental areas. Therefore, it
is strongly recommended that these
systems be protected.
 The long collaboration
with major OLTC manufacturers has
resulted in the protection of every
type of
OLTC. This is why TPC strongly recommends
protecting all of them, using a flange
for depressurization and a pipe that
goes to the bottom of the OLTC to
eliminate explosive gases.
Oil
Bushing Cable Box (OBCB)
Examples exist
where 300 liters (80 gallons) of
burning
oil from
OBCBs
have destroyed a complete plant.
OBCBs are not protected at all against
explosion,
as they are never equipped with pressure
relief devices. Therefore, burning
oil is often expelled onto the transformer
and onto the floor, which results
in the fire spreading. To protect
the
OBCB, 2 flanges are necessary for
the Transformer Protector adaptation,
one
to depressurize the OBCB and the
other to inject nitrogen in order
to eliminate
the explosive gases.
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Transformer Protector
MTPAB Type
protecting tank, 1 OLTC
and 3 OBCBs
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Optional
Items
| • |
Autonomous
Dry Battery with Associated
Low Reserve Alarm |
| • |
System Actuation Audible
Warning |
| • |
Cabinet Heater with
associated thermostat |
| • |
Decompression Chamber
Heater for very cold
climates |
| • |
Manual Nitrogen Injection
Valve |
| • |
Adaptation for OLTC
Oil Filtration Unit
Heat Exchanger for the Explosive Gas Evacuation Pipe |
| • |
Insulating flanges
for transformers protected
with Earth Fault |
| • |
Engineering and on
site drawings (Solid
Works files only) |
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