Oil filled transformer has circuit interrupter disposed within the transformer housing and utilizes a bridging contact movable between an open position spaced from a pair of stationary contacts, and a closed position engaging the stationary contacts, to complete a series circuit through the transformer to a low voltage terminal located on the transformer housing.
A bimetal actuating means which is disposed in series in the circuit through the transformer is connected so that when current flow there through exceeds an overload trip value, the bimetal actuating means moves the latch to an unlatched position, permitting the circuit interrupter to trip open. The bimetal is responsive to the temperature of the surrounding oil and deflects when the oil is heated for any reason. The oil in contact with the winding and core rises as it absorbs the heat.
Oil filled distribution transformer consists of a transformer tank defining a hermetically sealed chamber, a transformer core-coil assembly disposed in said chamber, cooling oil surrounding the said transformer core-coil assembly, and at least partly filling said chamber, said transformer tank being made of a corrosion-proof composite material, and a radiator external to said sealed chamber and having a hot oil inlet and a cool oil outlet located at different levels into said sealed chamber for causing a natural circulation of oil through said radiator by thermal siphoning. These transformers may also have external radiators to provide greater surface area of cooling. Oil filled distribution transformers are used for low voltage distribution and offer a cost-effective solution.
In terms of application, the oil filled distribution transformers market can be classified into industrial, commercial, and residential. The industrial segment accounted for major share of the market in 2017. This trend is expected to continue during the forecast period. The residential segment is anticipated to expand at a significant pace during the forecast period.