33kV Oil Immersed Distribution Transformer with Conservator

  1. Transformer with conservator tank (S),

  2. Hermetically sealed type (SM),

Below table will help to engineers to select the best option according to environmental conditions which transformer works in:

Meanwhile here is the advantage-disadvantage of the S/SM types:

• In SM type, tank pressure is more than S type. S type generally works under low pressure due to its open to atmosphere,

• In SM type, cooling/insulation oil does not contact to the air (theoretically). Therefore oil maintenance period is longer than S type,

• SM type transformers and their related parts generally work under higher temperature (If we evaluate S/SM work under same conditions).

Transformer with conservator tank is the same as hermetic transformers with core and coil structure. The dimensions of the conservator tanks of this type of transformers are designed and manufactured as a result of calculations to store the conservator of the oil whose volume increases with temperature.

Since the transformers with conservator tanks are open to the atmosphere, the oil pressure is changed due to thermal effects, and the air exchange is ensured by taking the moisture of the air through the silica gel (air dryer) in the transformer tank.

As a result of the air exchange due to the temperature differences after usage, the transformer with the working conservator tank loses its silica gel properties over time and causes the humidification of the oil and its structure. For this reason, it is necessary to carry out maintenance such as changing the silica gel and measuring the puncture voltage by sampling the oil.