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Oil Purification Methods GlobeCore

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Oil Purification systems

Classic Ways of Used Oil Purification

In today’s industrial environment, all the Used Oil Purification Methods are divided into such groups as:

  1. Physical Used Oil Purification Method;
  2. Chemical Used Oil Purification Method;
  3. Combined Method of Used Oil Purification.

A particular purification method is chosen depending on the amount and the degree of the used oil’s contamination.  If oil is contaminated only with mechanical impurities, then it may be enough to carry out a simple purification.  But sometimes, oil that is very contaminated should be processed by chemical reagents.

Transformer oil purificaiton

Transformer oil purificaiton

Physical Oil Purification Methods

Physical methods provide for removing only mechanical impurities such as sand, dust, metallic particles, resinous, and coke-like and carbon materials.  In this way, the chemical base of the oil being processed remains unchanged.

In practical terms, physical methods such as sedimentation, filtration, centrifugal separation, distillation of fuel and water washing have gained a widespread acceptance in the industry today.

Sedimentation

Sedimentation is considered to be the first, and a necessary stage of the purification process. It consists in quiescent sedimentation of mechanical impurities and water that are in a suspended state.  In this case, gravitational force plays a very essential role.  According to the Stokes equation, we may say that the greater size and the specific weight of the mechanical particles, the faster the mechanical particles will settle down.

Metallic particles, resinous substances and coke-like materials are more likely to settle down than any other substances.  It is worth mentioning that the  used oil sedimentation method does not always lead to the desired effect.  Sometimes, even when the processing time is increased, the majority of the impurities will remain in a suspension phase.  This always happens when purifying used diesel and automobile oils that contain dispersing additives  as well as oils that are contaminated by finely divided additives.

Oil Separation

Separation features a centrifugal process. Centrifugal forces exert influence on the heaviest particles that tend to be drawn to the vessel walls thereby forming a circular sedimentary horizon. The second sedimentation layer consists of water when the third one – of purified oil.

 Oil Filtration

Filtration consists in separating inhomogeneous systems with diffusion barriers.  They are able to retain some particles and at the same time  give way to other particles.

Fuel Distillation

Fuel distillation is applied when processing oils from internal combustion engines.  It is impossible to obtain oil of the necessary viscosity and with the required flash point without fuel distillation.  The difference between boiling temperatures of oil and fuel is the basis for fuel distillation.   When heating up the used material, the fuel, and then oil, will start to evaporate.  When oil fractions start evaporating, the heat should be removed.

Water Washing

Water washing is applied if oils need to be cleaned from acid products (water-soluble low-molecular acids and soaps).  Water washing however, will not restore the performance characteristics of oil completely if it has become old and highly contaminated.  When acids are dissolved, water is separated from oil at 60ºС in the course of using the separation method.

Physicochemical Used Oil Purification Methods

Coagulation

Coagulation allows for improvement of used oil filtration as well as removal of impurities that are in a suspension state or have not been removed in the coarse of other physical methods.  Coagulation is a coalescence of colloid particles.  This method may be implemented if:

  1.  to add special agents to oil (electrolyte and non-electrolyte fluids);
  2.  to perform mechanical effects (blending or shaking);
  3. to heat or to cool the oil;
  4. to pass the electric current;
  5. to use radial energy.

In each case, coagulation occurs since the connection between contaminated particles and their dispersed medium become weak.

Substances that cause coagulation are divided into four groups such as:

  1. electrolyte fluids (trisodium phosphate, calcinated water). They create a double electric field on the surface of the particles;
  2. ionic surface agents with active organic cation or anion;
  3. non-ionic surfactants;
  4. Surface-active colloids and hydrophilic high-molecular compounds.

The following is a description of a common coagulation procedure. At the first stage, oil is heated up to between 75º and 90ºC and then is blended with a 10% solution of coagulant for between 20 and 30 minutes.  Then it is allowed to settle down for 2 days.  Oil is treated on a special equipment after the sediments are removed.

Adsorption

Adsorption consists in retaining impurities on the surface of adsorber material.  The latter is able to retain asphaltic resinous substances such as acid compounds, ethers and other products of aging.

The distinctive feature of this method is that it is easy-to-perform and can be used to purify the majority of the used oils.  Substances such as silica gel, aluminium oxide, bleaching clays and silica-alumina catalysts may serve as adsorbents.

The majority of them are artificial and very expensive.  Bleaching clays however, are an exception since they have good adsorption properties and are typically derived from deposits commonly found most everywhere in the Earth.

ChemicalUsed Oil Purification Methods

Sulfuric Acid Refining

Sulfuric Acid refining is one of the oldest, but still one of the most effecive methods of oil purification.  It is used in the oil industry to remove  asphalt resinous substances,  acid containing and sulphur containing compounds, as well as other hazardous impurities.  Sulfuric acid refining results in obtaining a substance that is divided into two liquid phases.

On top, there is acid oil and on the bottom, an acid sludge.  Almost all hazardous wastes (except organic acids) are removed from the used oils together with acid sludge though the majority of the oil’s carbons will remain unchanged.

Alkali Purification

Alkali purification may be:

  1. an independent stage of purification;
  2. an initial phase of the alkali-earth purification;
  3. a final phase of  sulfuric acid refining.

Usually, caustic soda, calcined soda and trisodium phosphate are required to carry out the alkali purification.  As a result of the purification, there are sodium salts (soaps) that can be easily turned into the alkali solution. Additionally, soaps are usually easily and well dissolved in hot water.

When alkali purification is complete, oil should be allowed to settle down.

Combined Methods of Used Oil Purification

Taking everything into consideration, it is clear that oil should be processed by more than one recgonized method to obtain the desirable effect of the purification process.  In practical terms, a combination of methods is applied to purify oil.  GlobeCore is in the business of purification and regeneration of different types of mineral oils using classical as well as new and innovative methods.  GlobeCore’s advanced technology provides for the complete restoration of the performance characteristics of dielectric oil and other industrial oil and fluids while at the same time reducing operating costs and maintenance costs.

With GlobeCore equipment, you will be able to reduce your need to spend money on new oil purchase since regenerated oil is restored to its new like condiction and des not need to be replaced with expensive new oil.

The fact that GlobeCore equipment is environmentally friendly is of great benefit to the power transmission industry.  GlobeCore oil purification units produce no hazardous waste.  Adsorbent materials, used in GlobeCore equipment, are reactivated directly in the unit and may be used for between 2 and 3 years before being disposed of as non-hazardous waste.

Canada. The CMM-4/7 unit for oil reclaiming successfully services transformers of wind turbines

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Oil reclaiming extends power transformer service life fro 15 years.

GlobeCore is a member of the American Wind Energy Association (AWEA), and always tries to find solutions to the urgent problems in the industry.

Among the tasks are: increasing reliability and extending service life of wind turbine transformers. These transformers convert the voltage of turbine generators for power lines. They are positioned within the tower or near the tower base.

Recently one of GlobeCore CMM-4/7 oil reclaiming units started operation on a wind farm in Canada. This equipment is designed for degassing, removal of free and dissolved water and solids from insulating oil. Also, it heats the oil before filling transformers and other electrical equipment. The secret to high performance of the CMM units are the activators that contribute to instantaneous evaporation of gases and water from oil.

The unit is compact and portable. It quickly services the wind turbine transformers located in remote areas.

CMM oil reclaiming units are available with a wide range of additional options:

  • additional vacuum system for vacuumizing of transformers;
  • two-stage refrigeration system to increase the efficiency of the vacuum system;
  • moisture sensors at both input and output of transformer oil;
  • remote control and oil reclaiming process monitoring;
  • thermal insulation;
  • metal container;
  • special room for the operator;
  • explosion-proof;
  • mounted on wheels;
  • trailer or semitrailer.

GlobeCore equipment for maintenance of wind turbine transformers:

  • Improves alternative energy transmission;
  • Extends the lifetime of the transformer;
  • Saves money on purchase of new insulating oils.

Oil Reclaiming and Oil Degassing Unit CMM-0.6 Launched in Italy

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October 2016: GlobeCore technical support team commissions an oil reclaiming and oil degassing unit CMM-0.6 in Italy.

The oil reclaiming equipment will be operated in Carpenedolo, Brescia. The CMM-0.6 is a portable oil station that purifies electrical insulating oils, removing mechanical impurities, water and gas. It guarantees the desired oils parameters for oils with viscosity less than 70 cSt (at 50°C).

The equipment is in demand among facilities dealing with installation, repair and operation of oil-filled high-voltage equipment (high-voltage switches, power transformers, etc.).

Depending on the type of oil reclaimation needed, the station operates in oil heating mode, or in thermal vacuum mode, filtering and cleaning the oil.

Specifications of the unit for oil reclaiming  and oil degassing can be found here. Use the “Contact” tab to receive buying advice on the CMM-0.6.

Successful Start up of CMM-12R unit for Oil Reclamation in Ecuador

News,

August this year, our company visited the city of Quito (Ecuador), to start up a СММ-12R unit for Oil Reclamation

The startup was preceded by a test run, which demonstrated good results with reduced dielectric loss tangent of 0,7% at 90° C (initial value at 11%) and increase of breakdown voltage to 80 kV.

The main feature of the CMM-12R plant is the round the clock regeneration of transformer oil without stopping for sorbent reactivation. Moreover, the equipment has an advanced software suite and can be controlled through a GSM-module. The unit  also operates without oil loss.

A special room with air conditioning and a personal computer makes the operator’s work easier and more comfortable. In regeneration mode, the CMM-12R unit for Oil Reclamation has a capacity of 4 m3 / hr.

Personnel training took place in Ambato, a city in the centre of Ecuador, where electrical insulation oil was treated in an on-line transformer without taking it offline. Operated in the mountainous area, the GlobeCore equipment demonstrated consistent results in oil regeneration.

Tricks and Traps of Oil Reclamation

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Ecological conservation and environmental concerns have become a much greater influence in production facilities around the world in recent years.  Concerns with environmental protection can also be found in the heart of major industrial operations such as steel mills, paper mills, sugar mills and processing plants. Conservation, oil reclamation and recycling of used oils can be a profitable and environmentally beneficial activity.

The engineering or technical manager of a large plant is often so busy managing production and ensuring optimal production with minimal downtime, that he does not have time to concern himself with the service life of oil that operates the plant machinery.  After all, the plant’s purchasing department looks for the lowest priced oil  and the handling/storage department ensures that all drained lube oil is disposed of via a waste removal company.

Various local, state and federal authorities have set regulations for the handling and disposal of used oil products.  The U. S. Government’s Environmental Protection Agency (EPA) has also issued its own used oil management standards, and companies are required to comply with them.

Reclaiming oil accomplishes the following:

  • Conserves a valuable resource;
  • Prevents contamination of the environment;
  • Saves money by reducing waste disposal costs; and
  • Reduces long-term liability for disposed products – from beginning to end.

When to Reclaim and When to Recycle Oil

Oil Reclamation vs Oil Recycling

Oil Reclamation and recycling are two related processes, but there are significant differences between them.

Oil Recycling As an Option

The plant engineer does not have to be concerned with the details of the technology used by a recycler, and therefore, is not the focus of this article except to provide guidelines for its use in the plant.  It is important to ensure that recycled lubricants are handled and processed in an environmentally acceptable manner.  Ask the removal company to show an independent environmental audit of its site and processes. Ensure the company is licensed to process used oil and make regular visits to the site.

Oil Reclamation

Reclamation treats a specified amount of used oil, preferably on-site, and returns the oil to the machine it was operating in for continued use.  An example of this is the reclamation of transformer oil, hydraulic oil and turbine oil.  Reclamation may take place off-site where the vendor of the reclamation service drains the existing oil and replaces it with previously reclaimed oil. Oil Reclamation generally involves cleaning, drying and perhaps adsorption to remove dark color, acids and sludge.  The reclaiming of used oil is essentially a non-chemical process that restores oil for reuse in a lubricating or insulating system.

Oil Recycling

All oil products eventually reach the end of their useful service life and must be drained from the machine or system, whether it is in an engine, a gearbox, a hydraulic system or in a turbine.  Oil that is recycled could be rerefined to new base oil or treated and sold as fuel oil.

Focus on Oil Reclamation. Traps of Oil Reclamation

Hydraulic oils, transformer oils and to some extent turbine oils, lend themselves to being reclaimed. But, one must ensure that the oil’s performance characteristics and specifications have not been downgraded after reclamation.  Reclamation usually involves the used oil being filtered and the removal of debris, sludge and fine particles.  Centrifuging is used to remove suspended particles and some water. Many transformer oil reclamation units dry the oil and achieve this by heating the oil and applying a vacuum to pull out moisture.

Transformer oils are frequently reclaimed through filtration.  This may take the form of centrifuging, vacuum dehydration or absorption with fuller’s earth or another activated media.  When considering a reclamation service for transformer oil, check the following:

  • Service providers should offer references of successful reclamation of transformer oil at other companies. Ask to contact previous clients;
  • Decide on the performance target for the transformer oil in consultation with the oil supplier or an independent consultant;
  • Test the oil before and after reclamation to ensure compliance with your target;
  • Ask for a certificate of analysis after reclamation; and
  • The certificate should show breakdown voltage, moisture content, acid neutralization number and power factor.

Turbine Oil

Great care must be exercised with turbine oil when carrying out the reclamation process. Centrifuging and filtration will remove particles and water, but the turbine oil must continue to perform its task of cooling, sealing, lubricating and corrosion prevention.  Even though the application is critical, turbine oil volumes warrant the reclamation effort.

The key to turbine oil reclamation is evaluating its performance under specified test procedures. Turbine oil is reclaimed by a combination of filtration, sweetening with fresh oil and sweetening with additives. The combination results in the removal of fine particles, sludge and water, and restoring the performance level.

When considering a reclamation service for turbine oil, check the following:

  • Ensure lube supplier works closely with you on testing;
  • Obtain a test certificate on the performance of the new oil;
  • Test reclaimed oil prior to refill to ensure compliance with performance target;
  • Check compatibility. Ten to 15 percent of the old oil can remain in a turbine system.
  • Perform quality tests through an independent lab to verify beginning and ending oil condition and performance capability; and
  • Verify oil performance after reclamation with bench tests such as Rotating Pressure Vessel Oxidation Test (RPVOT) (ASTM D2272), viscosity, AN, foam, demulsibility and color.

Hydraulic Oil Reclamation

Hydraulic oils are a complex mixture of carefully selected base oils and specific additives.

Top-tier hydraulic oils, often called anti-wear (AW) hydraulic oils, must meet performance specifications set by original equipment manufacturers (OEMs).  They must also meet standards set by hydraulic pump makers and standards organizations such as Deutsches Institut für Normung (DIN) and the American Society of Testing and Materials (ASTM).

Plant engineers are increasingly interested in extending the service life of hydraulic fluid.  As a result, suppliers and consultants are often asked ways to carry this out.  Because of their high-pressure operation, hydraulic fluids tend to accumulate silt.  Silt must be eliminated to avoid valve sticking and polishing wear.  Hydraulic oils and fluids are reclaimed by a combination of filtration, vacuum dehydration and adsorption. The combination results in the removal of fine particles, sludge and water, and restoring the performance level of the fluid.

Traps of Oil Reclamation

When considering a oil reclamation service for turbine oil, check the following:

  1. Ensure reclamation vendor can show proof of previous success;
  2. Obtain from the vendor a certificate of analysis at the end of the reclamation. Compare this to the condition of the oil before reclamation;
  3. Be sure you understand the performance capability of the new oil and the performance requirements of the OEM. Test against those standards;
  4. Perform quality tests through an independent lab to verify beginning and ending oil condition and performance characteristics; and
  5. Test certificates/records should be filed for the next oil change.

After finding a reputable and trusted reclamation vendor, the key is to assemble a team to manage the process.

The Reclamation Team

Managing used oil recycling or reclamation is often left to an individual or is completely neglected in a plant.  It is useful to form a team to focus on the process if there is sufficient volume of used lubricating or process oil at the site to justify reclamation.  A recycling and reclamation team may consist of a buyer, lubrication engineer, maintenance engineer, oil supplier representative, a reclamation company representative and an environmental officer.  They work together to improve the recycling program.  In doing so, they compile the information found in Table 1.

The team of Oil Reclamation

We are partner of ABB

The manager of the plant will have to make a decision between reclamation and recycling for his used lubricants and process oils. Because lubricants have different processing requirements, some lubricants are not good candidates for reclamation.  The waste oils should be broken into two categories, for either reclamation or recycling.

If it is not clear whether the used oil stream is a good candidate for reclamation, contact the reclamation company and ask whether the specific product, by product name, can be reclaimed.

Candidates for consideration may include:

  • Cutting fluids;
  • Hydraulic oils;
  • Turbine oils;
  • Transformer oil;
  • Spent lube oils; and
  • Engine oils and gear oils.

Using Recycled Oil

Reuse of waste oil can include:

  • Burning without treatment – not advised;
  • Reprocessing to industrial fuel;
  • Re-refining to new oil; and
  • Disposal to landfill – avoid at all costs.

Note that the EPA has specified that used oil that does not meet the following criteria must be classified as “Off-Specification.”  This used oil may be used as a fuel only in an industrial facility registered with the EPA.  These include cement mills, lime kilns, coke ovens and blast furnaces.

If the halogen content is greater than 1,000 ppm, then the used oil must be managed in accordance with the Federal Resource Conservation and Recovery Act (RCRA) hazardous waste regulations.  While all lubricants eventually reach a condition where they can no longer be used and must be discarded as used lubricating oil, the plant engineer can examine the following options for minimizing the volume of used oil generated:

In-line oil sensors to ensure that oil life is extended and unnecessary oil changes do not occur.

  • Use of oil mist lubrication on industrial gear boxes and other equipment;
  • Choice of extended drain period diesel engine oils for fleets;
  • Selection of equipment with reduced oil volume sizes;
  • Improving the filtration of the lube oil charge and dosing with additives; and
  • Prevention of oil contamination.

Every plant should have a coordinated plan for managing used lubricating oil. Cleaner production methods and waste minimization should be the first initiatives in reducing waste oil at a factory.  When lubricating oil reaches the end of its projected service life, it must be either reclaimed or recycled.

If reclaimed, the lube oil may continue to serve its intended function for many more operating hours. Rigorous testing and record-keeping are necessary for this approach.  If the waste oil is a mixture of contaminants and spent oils, then the used lube oil can be reprocessed by a contracted recycler, keeping within local government regulations.  Every business should keep track of the used oil it generates once it leaves the plant.  Plants that generate large volumes of used oil should seek an independent report on the process practiced by their contracted recycler.

Used Oil and Environmental Issues: Oil Reclamation is the Best Solution

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Problems with mineral oil usage and its disposal are usually closely connected.  In today’s modern industrialized world, used petroleum products are one of the most widely found industrial waste products.  Used oil can be a threat to the environment by contaminating the soil, water and the atmosphere.

Approximately twenty percent (20%) of  contamination found in water resources is caused by human activity.  Used oil accounts for sixty percent  (60%) of this unwanted contamination.

There is no doubt that used oil reclamation is of a great importance.  Used oil disposal by means of combustion causes even more environmental problems.  That is why used oil waste products have both an economic significance and environmental significance.

Water resources and soil can become contaminated due to used oil drainage and leakage, while the atmosphere is polluted by the burning of used oil products.  GlobeCore is a modern company that supports the idea of solving environmental issues. GlobeCore believes that it is better to prevent possible contamination in the first place thereby and eliminating the consequences before they happen.

Large amounts of financial and human resources are spent each year to clean and/or safeguard the environment from man made pollution.  These efforts are not enough however, to completely solve the man made waste problem.  That is why new and more environmentally safer technologies and equipment are needed throughout all industrial sectors.

Used oil reclamation equipment from GlobeCore is now being delivered to private and public companies all over the world.  The GlobeCore used oil reclamation /regeneration units are able to restore used oil to its original new like condition thereby eliminating the need to dispose of the used oil.

Thus the chain of buying, using, and disposing and replacing is broken.  Used oil will not get into the soil and waterways because it is being restored and placed back into service.  Moreover, it is still used in the industrial cycle.  The Globecore Process eliminates oil waste and reduces the need to buy new replacement oil.  The environment wins and your company will save money.

Modern oil reclamation technologies for oil processing will increase oil filled equipment reliability and reduce maintenance and operating expenses.  The uniqueness of GlobeCore technology is best demonstrated by the careful and energy efficient processing of transformer oil.  This helps both to eliminate undesired impurities and to restore the oil’s performance characteristics back to acceptable international standards.

Restoring the used oil’s performance characteristics is obtained through the application of a modern process that includes filtering, heating, evacuation and replacement back to the oil filled equipment.  This is all performed without having to replace the sorbent materials since the sorbent is reactivated without the need for disposal.  The GlobeCore Process therefore, is the most environmentally friendly oil restoration process in the world today.

The GlobeCore reclamation process saves the environment and saves you money.

The schedule of transformer oil maintenance oil type transformer maintenance

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oil type transformer maintenance

The frequency of transformers maintenance depends on the importance, design features and durability of transformers. The first step towards a preventive maintenance program is testing. Testing helps us to determine when a treatment is necessary.

WHY DO WE NEED TO CHECK TRANSFORMER OIL?

Transformer oil is an insulator between the metal parts of the transformer and the wiring within the tank. Over time, the oil can be contaminated with moisture or create combustible gases. By sampling and testing that oil, we can plan repairing or replacing the transformer before a failure occurs.

Maintenance Schedule for Oil Filled Power Transformers

Maintenance or Test

Recommended Interval

 

Reference

Transformer physical inspection

 

Annually

Leakage of oil and reading of MOG (Magnetic Oil Gage) of tanks

Daily

In case of unsatisfactory oil level in the MOG, oil to be filled in transformer and also the transformer tank to be checked for oil leakage. If oil leakage is found take required action to plug the leakage. If silica gel becomes pinkish, it should be replaced.

 

Dielectric strength test (BDV) and moisture content (PPM).

 

Annually

A dielectric strength is a measure of the voltage which is conducted by the transformer oil. At times it is the presence of contaminants which conduct electricity faster than the oil which in turn lowers the dielectric breakdown voltage

Neutralization test

 

Annually

This test which is carried out to ascertain the level of acid which is present in the oil. When oxidation occurs in the transformer oil, it leads to build-up of acid.

Dissolved Gas Analysis Test (DGA)

Annually for 132 KV transformer, once in 2 years for the transformer below 132 KV transformer and in 2 years interval for the transformer above 132 KV transformer.

 

It helps to analyze the gases which are present in the transformer oil.

Bushings– check of oil level

 

Weekly

If it is required, the oil to be filled in the bushing up to correct level. Oil filling to be done under shutdown condition.

 

Bushings –visual inspection

 

Annually

Bushings – visual inspection and cleaning

 

5 years

Interfacial tension test

This is a test which is carried out to detect the presence of polar compounds such as paint, varnish and paper.

Tan & delta test

One in two years

Finally the presence of water too is measured as water can decrease the dielectric breakdown voltage of the transformer oil

Colour test

This test indicates aging, quality and the presence of contaminants in the transformer oil.

Transformer excitation current test

 

5 years

Insulating oil   – DGA, physical,

and chemical tests

 

Anually

Top oil and winding thermometer

Inspection

 

Anually

Oil level indicator operation

 

5 years

Sudden pressure relay

5 years
oil type transformer maintenance

oil type transformer maintenance

So, for getting high performance and long functional life of the transformer, it is desired to perform various maintenance activities. GlobeCores’s oil reclamation equipment will keep your transformer oil in the best condition, providing with oil degassing, water and solids removal as well as acids reducing. It’s a fantastic transformer life!

GlobeCore Has Presented its Equipment in Armenia

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In February, GlobeCore staff delivered another presentation on its equipment.

GlobeCore managers visited Yerevan in order to meet with representatives of the power industry in Armenia.  The peculiarities of equipment, designed to purify and regenerate transformer oil and maintain power transformers were the main topics of the lecture. All the questions arouse were satisfied.

After the samples of used oil were processed on the GlobeCore unit, the people present had no doubts that GlobeCore equipment was able to solve even the most complicated tasks. It is easy-to-use and eco-friendly, reduces operational costs and valuable raw material.

In general, both parties were very satisfied by the results of the meeting. GlobeCore has gained new experience communicating with specialists of the electric power industry and the representatives of Armenia have received a great possibility to solve the problems, accumulated for decades.

Transformer Damage and Oil Regeneration/Oil Reclamation

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An electric power transformer Damage is one of the most important elements of the modern electric grid no matter where in the world a particula grid may be located.  Transformer failures result in significant financial expenditures, and will require the transmission company to buy new transforners or repair the damaged ones at significant cost and service interuptions.

Many historians note that there was great industrial boom observed in the first decade followintg the end of World War II.  At that time, there was a rapid increase in electric power consumption.  To meet the growing demand for electric power, new transformers had to constantly be put into operation.  Since that time, mant of the older transformers have become outdated and pose a big risk of unscheduled service interuptions.

Older transformers’ obsolescence however, is not the only problem facing the modern power grids.  The power loads on the obsolete transformers are increasing because of ever increasing power consumption.  It requires significant expenditures to replace the broken or obsolete transformer since the price for a new transformer is very high.

It is therefore, advisable to take measures to extend the service life of transformers already in service.  To succeed in undertaking a sucessful preventive maintenance program, one should understand the nature of the failures that make transformers unserviceable in the first place.

In 2003, the International Association of Engineering Insurers (IMIA) started to explore the reasons for transformer failures servicing the combined USA power grids.  The results were rather interesting.  Table 1 shows the economic losses caused by different types of transformer failures.

Table 1

Economical Losses Caused by Different Transformer failures

Nature of Failure

Amount of Cases

Economical Loss in $
Insulation defects

24%

149,967,277.00
Problems with designing, material or installation

22%

64,969,051.00
Unknown failures

15%

29,776,245.00
Oil contamination

4%

11,836,367.00
Overloading

5%

8,568,768.00
Inflammation/explosion

3%

8,045,771.00
Network overvoltage

4%

4,959,691.00
Operational failures

5%

3,518,783.00
Water ingress

2%

2,240,198.00
Poor contacts

6%

2,186,725.00
Lightning stroke

3%

657,935.00
Insulation moistening

1%

175,000.00
In total

94%

286,628,811.00

It is not an overstatement to say that if proper and timely preventive maintenance of the insulating systems is performed, many, if not all transformer failures can be prevented.  The insulating system of the power transformer consists of bith solid and liquid insulation.  The solid insulation is made of hygroscopic material (cellulose) also known as “Kraft Paper.”  The liquid insulation features a dielectric fluid known as transformer insulating oil.  In general, these two kinds of insulation are interdependent, but also help to contaminate each because degradation products from the solid insulation may get into oil and oil oxidation sludges may penetrate into the solid insulation from the oil.  Simply changing the transformer oil therefore, will not completely resolve the problem of restoring and cleaning the entire insulation system.  Unfortunatelt, oxidation products are accumulated in the cellulose insulation and are not removed when oil is simply changed.  And when only an oil changed is performed, these oxidation products will migrate get into new oil accelerating the aging process of the new oil and shortening its effective service life.  Additionally, the contamination that remains in the solid insulation will continue to degrade and damage the Kraft Paper leading to transformer failure.

This problem may be solved with the advanced GlobeCore regeneration technologies.  The GlobeCore mobile oil recycling stations, designated as the CMM-R line of equipment may be connected to either an energized or non-energized transformer.  In such a way, oil is circulated through a closed path: used oil flows to the oil treatment station and goes back to the transformer being cleaned and restored.  The contaminants resulting from the aging process are washed out due to the constant circulation. This advanced type of equipment performs a complete oil regeneration service and removes all contamination for the transformer core, windings and solid insulation.

GlobeCore mobile oil stations perform  the following operations:

  1. filtration with or without heating (processed oil is of 9th ISO 4406 purity class and with nominal filtration fineness, ranging from 0.5…1 micron);
  2. dehydration (the moisture content of the processed oil is no more than 5 g/t (5ppm);
  3. degassing (volumetric gas content of the processed oil is no more than 0.1 %);
  4. increase the dielectric breakdown voltage (no less than  70 kV (kilovolt));
  5. drying of electrical equipment and oil purification simultaneously;
  6. regenerate insulating oil, using bleaching clay;
  7. vacuum transformers and other electrical equipment;
  8. remove acids;
  9. remove soluble oil decomposition products;
  10. lighten insulating oil; and
  11. restore oxidation and gasification stability;

The GlоbeCоre technologies provide for service life extension of transformers and reduction of financial expenditures on maintenance.  Save money with GlоbeCоre!

Reliability of Low Voltage Power Transformers

Case Studies Of Oil Reclamation, , , , , , , , , , , ,

GlоbeCоre’s oil reclamation technology has been proven to cost effectively regenerate transformer oil thereby increasing the operational reliability of electric transmission equipment.

Before electric grid restructuring started, units with a voltage of between 110 and 500 kV (kilovolt) had constituted the greatest part of the fleet of transformers.  But the things have recently changed, today power companies routinely use transformers with voltage that is less than 110 kV with the majority of the transformers having a capacity of  less than 35 kV.

Table 1 analysis of the reasons for equipment damage depending on the point of fault.

Table 1

Damage Sources for Transformers with Voltage up to 35 kV

No.

Type of Fault

Rate of the total % of faults
1 Winding faults

19
2 Bushing insulator

3
3 Insulation faults

21
4 Insulation moistening

8
5 Oil

5
6 Voltage regulators

23
7 Contacts in windings

15
9 Other

6

As we can see, the greatest amount of damage is the result of insulation faults. That is why the condition of transformer oil is of such importance.  The efficiency of the entire insulation system (both solid and liquid) largely depends on the quality and condition of the dielectric transformer oil.  Such factors as temperature extremes, interaction with the atmospheric oxygen, and the accumulation of emulsion water have a negative impact not only on the performance characteristics of oil, but also on the condition of the solid insulation.  As a result, transformers break down prematurely even though their service life should be much longer.

Unfortunately, once the transformer has experienced a catastrophic failure,  there is only one solution to this problem.   The failed transformer willl have to be replaced by a new one.  But, such a strategy requires significant capital expenditures and leads to reduced profits and inefficient operations.

The solution to this problem is to call GlоbeCоre who is in the business of designing and producing equipment for purification and regeneration of transformer oils.

GlobeCore promotes and adheres to the principle of “preventive maintenance.”  That means that the causes of transformer damage are prevented in the first place during transformer servicing.  It is transformer oil purification that helps insulting oil maintain its performance characteristics at the proper level and slows down the process of its aging.

GlоbeCоre produces equipment that allows for complete processing of transformer oil (purification, dehydration, and degasifying) to restore the original performance characteristics of the dielectric oil.

GlоbeCоre equipment is also very eco-friendly: there are no harmful discharges into the air since it uses the sorbent that can be reactivated to prevent the penetration of oil residues into water and soil.  The service life of transformers with a voltage up to 35 kV may be extended by 10 years if negative impacts are reduced.