Network Transformers - Augier

LINE DEAD END SPARKS GAP
Network in TNRS* diagram with a concentric two-pole cable
The peripheral conductors (neutral) of the concentric two pole 3.5/6 kV cable are insulated to 1000 V level. In the
event of using this cable with a TNRS distribution system, accidental damage to cable will result in a short circuit
with the central conductor (3.5/6 kV); causing peripheral voltage to exceed the 1000 V limit to 3200 V. This can
also be caused by the primary winding of the TED transformer.
A line dead end spark gap results in a connection between the peripheral cable and the earth. An overvoltage limiter
allows, in this case, a dangerous potential to pass the cable.
This will activate the differential protection installed in the delivered substations public lighting switchboards, on
the feeder concerned.
The transformer is delivered with a 2 m strap of 25 mm² concentric two-pole cable equipped with a universal cable
head, to be plugged into the terminal left unused of the last TED transformer of the line or of the deviation.
It is imperative that the earth terminal be connected to the small earth cable.
Brochures available on request.
FRONT VIEW TOP VIEW
MV NETWORK MAINTENANCE ACCESSORIES
These accessories enable operations to be carried out following recommended safety rules, in particular to test for
absence of voltage before intervention of TED transformer.
* TNRS diagram applies to cases where the cable periphiral conductor is maintained isolated at level of network transformers.
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