What is the difference between Type 1 and Type 2 transformer oil?
At present, there are many types of transformer oil on the market, of which mineral oil is still the most common choice due to its wide range of applications, a number of refineries are involved in its refining process. Transformer oils are divided into two main types: Type 1 and Type 2.
Type 1 oils have no added antioxidants, while Type 2 oils contain oxidation inhibitors, which help to slow down the ageing process of transformer oils.
Part of the ageing of transformer oil is caused by oxygen, which enters the transformer mainly through leakage. It is therefore vital that regular visual inspections are carried out and any leaks found are repaired. The effective life of the oxidation inhibitor depends on the oxygen content in the transformer: the higher the oxygen concentration, the faster the inhibitor is consumed.
Based on these considerations, it is recommended that Type 2 transformer oil containing an oxidation inhibitor be used to extend the service life of the transformer and to maintain stable performance.
How much oil is used in a transformer?
In oil-immersed transformers, the amount of oil is determined in relation to the type of transformer (fully sealed or open) and the rated capacity.
Fully sealed oil-immersed transformers:
– 500kVA fully sealed oil-immersed transformer has an oil capacity of 430L.
– 1000kVA fully sealed oil-immersed transformer requires 700L of oil.
Open type oil-immersed transformers:
– For the same capacity transformer, open type usually requires slightly more oil than fully sealed type. For example, a 500kVA open type oil-immersed transformer may require 450L of oil, which is more than the 430L of the fully sealed type.
Conclusion:
– The amount of transformer oil used is directly proportional to the rated capacity of the transformer.
– Open oil-immersed transformers usually require more oil than fully sealed types for the same rated capacity.
– The exact amount of oil should be determined by the transformer model, specifications and manufacturer’s recommendations.
What is the problem with transformer oil?
Transformer oil is a liquid used as an insulating and cooling medium in oil-immersed transformers. The quality of transformer oil is critical to the safe operation and service life of the transformer, common problems with transformer oil include:
– Excessive moisture: high moisture content promotes partial discharge phenomena, increasing the risk of equipment failure.
– Temperature imbalance: High temperatures accelerate oil aging, and low temperatures may also cause problems.
– Excessive oxygen content in the oil: Excessive gas can be a trigger for partial discharges.
In order to avoid these problems, the following are some commonly used oil-immersed transformer oil precautions:
1、Control moisture
– Check the air bladder regularly, if there is any oil leakage, it needs to be replaced with a new one in time.
– Monitor the colour change of desiccant and replace it when its capacity drops to about one-third.
2、Maintain oil temperature
– Check for overload, cooling unit failure or internal failure.
– Ensure that the cooling unit is functioning properly and deal with any faults immediately or reduce the transformer load.
3、Inhibit oxygen
– For new oil, add appropriate amount of antioxidant.
– Regularly on the operation of the transformer oil for laboratory testing, determination of oxidation indicators, and in excess of the standard add antioxidants or replace the new oil.
How does oil type transformer work?
The design of oil-immersed transformer is similar to that of conventional transformer, which mainly consists of three parts: the core in the centre, the coil around it and the casing.
– The core and the winding: together they generate a magnetic field that allows current to pass through. The windings have an insulating layer, the thickness of which increases with the voltage level.
– Bushing: responsible for the safe transmission of the current to the next station, usually a substation.
Oil-immersed transformers rely on the principle of electromagnetic induction to convert the input current to a higher or lower voltage. This process generates heat, and transformer oil acts as a key heat sink and insulator. The windings and core are completely submerged in the oil, which prevents the equipment from overheating by circulating oil convection. At lower voltages, the transformer oil is further dissipated by an external cooling system; at higher voltages, it is cooled more efficiently by air-cooled radiators.
