What is Onan ONAF transformer?

ONAN means Oil Natural Air Natural (When the oil is circulated in oil fins without any forced measure, it is called oil natural and air on the fins goes by nature. ONAF means Oil Natural Air Forced (The oil will be circulated without any forced measure but the air will be blown through fans).

What are the types of transformer cooling?

Cooling Methods of a Transformer

• Oil Natural Air Natural (ONAN)
• Oil Natural Air Forced (ONAF)
• Oil Forced Air Forced (OFAF)
• Oil Forced Water Forced (OFWF)

How many types of cooling methods are available for transformer?

The following two transformer cooling methods are adopted in dry-type transformers. Air Natural (AN) cooling – Cooled by surrounding air. Heat transfer by natural convection. Air Forced (AF) cooling – Forced sir circulation using fans and blowers.

What is cooling of transformer?

Cooling of a transformer is the process of dissipation of heat developed in the transformer to the surroundings. The losses occurring in the transformer are converted into heat which increases the temperature of the windings and the core. In order to dissipate the heat generated cooling should be done.

What is the difference between Onan and ONAF?

ONAF Cooling of Transformer The full form of ONAF is “Oil Natural Air Forced”. As the heat dissipation rate is faster and more in ONAF transformer cooling method than ONAN cooling system, electrical power transformer can be put into more load without crossing the permissible temperature limits.

What does KNAN mean?

KNAN is a transformer that uses less flammable non-mineral oil such as silicone oil, synthetic ester or natural ester (FR3) as the insulating fluid with natural air convection cooling. KNAF has same transformer oil as KNAN but with external forced air cooling.

What is the common method of cooling transformer?

Answer : A common method of cooling a power transformer is oil cooling.

Which is the common method of cooling a power transformer?

Oil cooling
The losses occurring in the transformer are converted into heat which increases the temperature of the windings and the core. In order to dissipate the heat generated cooling should be done. Oil cooling is the commonly used method for cooling purpose.

What are the important methods of cooling the transformer?

By Air Natural method the generated heat in the transformer is cooled by the circulation of natural air. When the temperature of the transformer becomes higher as compared to the temperature of the surrounding air, thus by the process of natural convection, heated air is replaced by the cool air.

Which gas is used in transformer?

Gas is used as an insulating and cooling agent in gas insulated transformers. Sulphur hexafluoride (SF6) is the main gas used in these types of transformer at present although other gases are under development.

Which oil is used in transformer for cooling?

Naphthenic mineral oil
Naphthenic mineral oil has long been the most preferred insulating liquid for power transformer insulation because it has a good pouring point at low temperatures, good thermal cooling capacity, low cost, high efficiency and availability on the transformers market [1, 2, 3, 7].

What is Onan cooling?

ONAN Cooling of Transformer This is the simplest transformer cooling system. The full form of ONAN is “Oil Natural Air Natural”. Here natural convectional flow of hot oil is utilized for cooling.

Which is better Onan or onaf cooling system?

The transformer above 5 MVA rating ONAN cooling system is not adequate and ONAF system is used to reject the heat developed in the transformer. Similar to ONAN, the oil circulates by convection process, however the force cooling to transformer tank and the radiator surface is provided by external cooling fans.

What is cooling class of transformer i.e.an Onan?

This type of cooling is called OFAF (Oil Forced Air Forced). In dry type transformer, there is no oil so entire heat is rejected in air. So fans are provided in transformer to cool the windings .

What does onaf stand for in a transformer?

ONAF (OIl Natural Air Forced) ONAF stand for Oil Natural Air Forced cooling. The schematic diagram of ONAF is as given below. The transformer above 5 MVA rating ONAN cooling system is not adequate and ONAF system is used to reject the heat developed in the transformer.

What is cooling class of oil filled transformer?

ANSI and IEEE require the cooling class of each transformer must be written on its nameplate. Depending on the process of heat transfer, the following types of cooling system is used in oil filled transformer. ONAN (OIl Natural Air Natural) ONAN stand for Oil Natural Air Natural cooling.