Self-protected or anti-theft distribution transformers are suitable to rural and urban zones.

The Distribution rural transformers are single-phase CHEMEL type, they can count on one or two high voltage insulators and they have a fuse incorporated.


Transformadores CH has developed self-protected rural transformers with a single phase, two-phases or three-phases, with grounding return. In the process of manufacturing of the transformer the costs have been reduced by eliminating those accessories that were no necessary, this without reducing the quality and its functionality.

1.1          Voltage and frequency of self-protected transformer.

Nominal: 50 or 60 Hz, according to the country.

Peru and Brasil:

23.000/231 – 60 Hz.

12.000/231 – 60 Hz.

7.620/231 – 60 Hz.

1.2          Capacities.

Self-protected two-phase rural transformers: 3-5-10-15-20 and 25 KVA

Self-protected single-phase rural transformers: 1.5-3-5-10-15-20 and 25 KVA.

1.3          Derivations

Self-protected rural transformers have a full capacity primary side of derivations, able to connect by epoxy changer of operations without voltage, outdoors type protected by weather type.

Derivations are according to the country.

  1. Constructive details

Design, construction and testing of self-protected rural transformers comply with the norm nº 76, CEI, about auto-refrigerated transformers immersed in oil that work outdoors.

2.1          Self-protected transformers pond

It is constructed with wieldable steel and has a sealed bolted cover. The minimum thicknesses is: walls 2,5mm and lid and deep 5 mm.

The transformer is protected all its life because its fond is sealed.

1.1          The transformer is easily fixable because the pole has 2 sealed rucksacks. Self-protected transformer nucleus

Self- protected transformer nucleus is enrolled, of siliceous steel, of great quality grain oriented that reduces the no load losses.

1.2          Self-protected rural transformers coil

Self-protected rural transformers coil is made of insulated wire with double layer of enamel. They are designed to guarantee the wide margins of security on insulation, coldness and resistance to high short circuits.

1.3          High voltage bushing (class 15 KV and 25 KV)

If there is an internal fault in self-protected or anti-thefts rural transformers, they have an epoxy bushing with high voltage protection incorporated that protects it insulating it from the line it is connected to. This fuse can be changed easily with a pole.

1.4          Low voltage bushing (class 1.2 KV)

Epoxy bushing that complies with the requirements of the norm for 1,2 KV.

  1. Advantages

2.1          Anti-vandalism

It is because its bushing is in epoxy resin.

2.2          Aseismic self-protected transformers

It is because its bushing is epoxy and one piece.

2.3          Bushing A.T. epoxy material that substitutes the single-phase disconnectors collocated in wooden crosspiece, in trunk line or in second position, deriving directly from the line to the self-protected transformer, with connected presses with poles.

2.4          Changer of epoxy derivations.

2.5          Epoxy low voltage bushing

If the customer wishes it, a protection box and derivation of electrical joints can be added to the self-protected transformer. It is a way to obtain more space and security.

2.6          Street lighting

For street lighting, it can be equipped with a special system that incorporates photocells in the superior part of the box with an input connector.

2.7          Self-protect or rural transformer has a plug wires bar of concentric joints; in the case it is necessary to use this wire.

2.8          The use of anti-theft or rural transformers is 33% more economic.

2.9          The installation of self-protected transformer is cleaner and they take advantage of the spaces of the pole.

2.10       DAE Transformers can be installed in ponds of 8.70 meters. It maintains the minimum altitude for a net A.T. and B.T. required by the norms.

2.11       Anti-theft or self-protected transformer is a development of Transformadores CH, which patent is #35450.