GEAFOL Neo

CUSTOMER BENEFIT

Built-in safety
The coils of the GEAFOL Neo’s high-voltage winding are manufactured
from aluminum foil. This foil winding combines simple winding
techniques with high electrical safety, because its insulation is
subject to less electrical stress than other types of windings. In the
case of a conventional round-wire winding, the turn-to-turn voltages
amount to double the voltage between layers. In the case of a foil
winding, however, no more than the simple turn-to-turn voltage
occurs because each layer consists of one turn. The result is great
power frequency voltage strength and impulse strength. In addition,
the epoxy-resin vacuum casting of the high-voltage windings is
performed at a high temperature, which avoids hazardous entrapped
gas and allows for a high level of freedom from partial discharges up
to twice the rated voltage. A high level of process expertise guarantees
excellent product quality as reflected in, among other things, an
excellent MTBF (meantime between failure) Index.
Reliable design
The conductive material for the low-voltage strip winding is also
made of aluminum, with the width of the aluminum strip practically
equivalent to the length of the coil in order to considerably reduce
the axial short-circuit forces in the transformer. It’s these characteristics
that make the design of the GEAFOL Neo possible. The conductive
and insulating materials are bonded to each other by heat treatment
and form a compact unit that also reliably handles radial forces.
The ends of the windings are encapsulated in resin.
Using vacuum switches with GEAFOL transformers
Transformers are the key operating elements at hubs in the
distribution system. Switches must control the switching of
distribution transformers reliably and safely, with no need for
overvoltage protection.
An important parameter in transformers is the magnetization
current, one of the “small inductive currents.” Interrupting these
currents naturally creates marked transients but no unacceptably
high switching overvoltages that would pose a threat to connected
distribution transformers are permitted.
Extensive trials using a combination of Siemens GEAFOL transformers
and vacuum switches have proven that the GEAFOL medium-voltage
windings can handle switching overvoltages with no difficulty –
providing further proof of their high product quality and operational
safety.