Tag Archives: oil lifecycle

How to Improve the Reliability of Electric Power Equipment with the Correct Transformer Oil

Tierra Fuller, ,

Transformer oils have certain technical and chemical parameters. These parameters define the scope of the oil’s applications and use.

The “Dissipation Factor” is one of the most important indications of oil quality and is a measure of the oil’s dielectric strength.  Aging causes oil to lose its performance capabilities and poses a threat to the safe operation of oil filled equipment.  Dielectric strength testing is a safety concern and must never be neglected.

The actual dielectric strength of the oil is mostly affected by the presence of solid particles, moisture, and other contaminates.  It is therefore, important to remove solid particles, water and other contaminates from transformer insulating oil to maintain the operating performance of the oil.  The best way to ensure the purity of your transformer oil is to use the GlobeCore Process performed by one of its various oil purification or oil regeneration units.

Another performance characteristic of oil is the oil’s viscosity rating.  An oil’s viscosity rating indicates the oil’s “resistance to flow” or “speed of flow” as measured through a viscometer.  The viscosity, or thickness of the oil can also affect the oil’s ability to transfer heat and cool the transformer.

Setting temperature and flashpoint temperature both help to indicate the allowable range of oil operation.  A “Low Setting” temperature is important when the oil is used in extremely cold climates.  A high oil flashpoint is important for reducing the potential fire safety concerns.

Another important quality of the oil is its oxidation stability, i.e. the ability to maintain its properties during prolonged use.  Oxidation stability is influenced by many factors, both internal such as antioxidant additives, reaction with metals, formation of gases in the oil, etc., and external factors such as moisture, air and temperature.  This parameter is important for the service life of both the oil and oil filled equipment.

Many oils, e.g. GK and TKp contain antioxidant additives which can extend the service life of oil to as long as 20-25 years.

Purchasing transformer oil from manufacturers and traders is not a problem these days.  Each company is competing and attempting to sell at the lowest price and offer the best service.

Transformer oil is an indispensible part of the insulation system of electric power transformers and other electrical equipment.  High purity and low viscosity are key in allowing your selected oil to be used in electric power transformers.

Depending on the actual equipment, transformer oils function as a dielectric liquid or, for instance, as an arc-extinguishing media in switching devices.

Quality oil has high dielectric strength, a low setting point, a high flash point, high oxidation stability, and the availability of convenient and practical transportation vessels.  High quality oil significantly extends reliable operation of oil filled electric equipment.

 

Above all, the oil in transformers and electrical equipment must be kept clean and free from moisture in order to provide the best possible service to your electrical equipment and prevent the need for unscheduled maintenance events.

It’s time to get with the Process.  The GlobeCore Process!

 

 

Which kind of Transformer Oil Should my Company Buy?

Tierra Fuller, , , , , ,

A great number of manufacturers and distributors of transformer oils operate in international and national markets.

Transformer insulating oil is a dielectric liquid that is intended for cooling and insulating electric power transformers and other high voltage equipment.  Transformers remain an indispensible part of the electric power generation and transmission industry.

In scientific terms, transformer oil is a product of crude oil refining.  The performance properties of transformer oil depend heavily on the quality and parameters of the raw material.  The performance of the oil is defined by the positive and negative properties of the crude oil.  Chemical composition of oil is quite complex.  It includes the following components: paraffin (10-15%), naphtenes or cycloparaffins (60-70%), aromatic hydrocarbons (15-20%), asphalt (1-2%), sulfuric compounds (<1%), nitric compounds (<0.8%), naphtenic acids (<0.02%) and antioxidation additive (0.5 – 0.5%).

Transformer oils must be highly resistant to oxidation and must not form sludge or emulsify when coming in contact with water.  Anti-oxidation additives are an important component and can be found in virtually all types of transformer oil.  When selecting an oil for your equipment, be sure to look for oils that have good antioxidant additives included since they will inhibit the oxidation process considerably better than uninhibited oils.

The efficiency of such additives is based on the ability of the additives to react with active peroxide radicals that form as the result of hydrocarbon oxidation reaction and are the primary carriers.  The presence of additives in transformer insulating oils slows the aging of the oil.  As soon as the additive is depleted, the oil ages in about the same amount of time as an oil without the the antioxidant additives.  Without the additives, the oil aging process will accelerate.

Two of the main characteristics of transformer oil are its viscosity and density.  These have a pronounced affect on the function of the oil.  Higher viscosity may mean better dielectric strength, but may reduce the ability of the oil to transfer heat and cool the transformer.  Optimal kinetic viscosity of the oil at 20 ̊C is about 28-30×10-6 m2/second.

The oil’s “Dissipation Factor” is responsible for the oil’s dielectric properties and protects the transformer’s electrical system from possible short circuits.

These and the other characteristics of transformer oil are improved by the use of high quality crude oil, deep refining and introduction of additives that increase the oil’s oxidation stability and reduce corrosion.

When oil is significantly oxidized due to the influence of water, solids, air and other gases, and high temperatures, the oil should be replaced.  If the degradation of the oil’s properties is not detected in time, transformers can and will fail.  When oil decays, it can no longer serve as a dielectric insulator and starts to react with the metal of the transformer tank and hinders cooling and may lead to short circuits.

The following are some of the different kinds of oils that may be purchased in the local market:

VG type oil is made from paraffinic crude oil by a catalytic process with the addition of an antioxidant  additive.  It is a good dielectric and is rather stable against oxidation.  It is mostly used in higher voltage equipment.

GK type oil is made of sulfuric paraffinic oils by hydrocracking.  It also contains ionol, an antioxidant, that ensures good stability and dielectric properties of the oil.  It is another kind of oil used in higher voltage systems.

TKp oil is made from low-sulfur naphtenic crude by an acid-alkali purification process.  The oil also contains antioxidant additives.  This oil is recommended for equipment with voltage up to 500 kV.

Oil selection depends not only on the type of electric equipment you are using, but also on the individual requirements of the facility.  Most of transformer oils are universal.  In all cases, the correct selection of oil type with consideration of local climatic and physical operating conditions ensures reliable and stable operation of electric power equipment such as high voltage transformers and switch gear.