Tag Archives: power transformer

The schedule of transformer oil maintenance oil type transformer maintenance

June 16, 2015Case Studies Of Oil Reclamationdielectric strength, equipment, GlobeCore, oil degassing, oil maintenance, oil reclaimer, oil reclamation, oil reclamation systems, power transformer, reclaim oil, regeneration, testing, transformer oil, transformer oil reclamation

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

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

June 16, 2015Newsequipment, GlobeCore, oil reclaimer, oil reclamation, oil reclamation systems, power transformer, reclaim oil, transformer oil, transformer oil reclamation, used oil

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

June 9, 2015UncategorizedCMM-R, drying, equipment, installation, oil, oil contamination, oil purification, oil reclamation, oil recycling, oil regeneration, oil treatment, power consumption, power transformer, Recycling, transformer damage, transformer oil, types, used oil

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:

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);
dehydration (the moisture content of the processed oil is no more than 5 g/t (5ppm);
degassing (volumetric gas content of the processed oil is no more than 0.1 %);
increase the dielectric breakdown voltage (no less than 70 kV (kilovolt));
drying of electrical equipment and oil purification simultaneously;
regenerate insulating oil, using bleaching clay;
vacuum transformers and other electrical equipment;
remove acids;
remove soluble oil decomposition products;
lighten insulating oil; and
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!

Oil Reclamation as a Method of Improving Power SubStations

June 1, 2015Case Studies Of Oil Reclamationmethod of improving power stations, new technology, oil reclaimer, oil reclamation, oil reclamation equipment, oil reclamation machine, oil reclamation plant, oil reclamation systems, oil reclamation unit, Power SubStation's Oil Reclamation, power transformer, reclaim oil, transformer oil, transformer oil reclamation, transformer oil regeneration, used oil

Uninterrupted transformer oil regeneration

Industry is always looking for new ways in how to improve the efficiency of existing electric power transformers since the price for new equipment has been increasing significantly in the past twenty years. Distribution substations and the transmission network are constantly working at peak or near peak capacity and that leads to much more rapid transformer wear and aging. Especially hard hit is the transformer’s liquid and solid insulation.

If the insulating system is in bad condition, the dielectric properties of insulating oil will be reduced. For such a prolem, GlobeCore has developed technology for the regeneration and purification of contaminated oil that restores the oil to its original new like condition. Using this advance new technology, oil is circulated through the special regeneration columns filled with Fuller’s Earth sorbent materials. Contaminated oil flows to the oil station and is sent back to the transformer in a clean, new like condition.

Since oil is continuously circulated through the unit, the contaminated oil residues are washed out from the transformer. Fuller’s Earth (a naturally-occurring sorbent) absorbs impurities and contaminants. The regeneration time will depend on the amount of oil that needs to be regenerated and the degree of its contamination.

GlоbeCоre equipment is desiged to work on energized transformers so there will be no, or minimal service interuptions. Another benefit of GlobeCore equipment is that its mobility allows the operators to serve multiple pieces of equipment in remote locations without having to evacuate the transformer to a repair or maintenance facility.

GlobeCore regeneration technology allows transformer services companies to:

(1) restore oil to its original like new condition;

(2) extend the service life of transformers and improve their efficiency;

(3) carry out “preventive maintenance” in order to eliminate the need for corrective mainatenance;

(4) greatly reduce the need to by new oil;

(5) eliminate the need to dispose of used oil; and

(6) eliminate the risk of service trouble during power equipment operation;

GlobeCore technology provides for transformer service life extension, reduction in financial expenditures and improvement of equipment efficiency. Contaminated oil residues significanly reduce the service life of windings and operational reliability of transformers. Aging of oil-cellulose insulation may lead to irreversible consequences during its expected service life.

GlobeCore technology increases transformer service life thereby reducing operating costs and improving operational reliability.

Contaminated oil residues reduce significantly the service life of windings and the transformer’s operational reliability. Despite the fact that oil-cellulose insulation may be used for more than 25 years, contaminated oil will cause premature failure of the transformer long before the transformer is ready for retirement.

Factors that have a negative impact on the insulation system of the transformer

GlobeCore’s Equipment is Environmentally-Friendly

Oil Regeneration is better than an oil change

It is better to regenerate oil than to simply change it. Products of degradation that have accumulated in the transformer’s solid insulation will get into the new oil within a few months of the oil change. As a result, the new oil will lose its performance characteristics much more rapidly than with the GlobeCore rengernation process.

GlobeCore equipment is considered to be revolutionary since Fuller’s Earth (the active adsorbent filtering system) is able to absorb products of degradation. Additionally, oil that is regenerated with GlobeCore equipment is much more resistant to aging. When only changing the oil, there is always up to 15% of the contaminated oil left in the transformer that will accelerate the new oil’s aging.

Due to advanced GlobeCore technology, all contaminated oil residues are washed out of the transformer by the hot oil being circulated through a closed loop that includes the regeneration equipment and the transformer.

GlobeCore’s regeneration technology is eco-friendly does not generate hazardous waste while regenerating transformer oil and other industrial fluids and oils. The Fuller’s Earth, used in the GlobeCore CMM-R line of equipment, absorbs all impurities and is reactivated directly in the equipment precluding the need to stop and dispose of used sorbent during the processing job. Each load of Fuller’s Earth will last up to 300 regeneration cycles before needing to be replaced.

GlobeCore CMM-R line of equipment

GlobeCore technology distinguishes itself through the following features:

Continuous autmoated and remote internet operation;
Operating Cost reductions;
Long-lasting oil and fluid purification effect;and
Complete removal of contamnants from oil and solid insulation.

Removing Contaminants from Transformers

If your comapny does not perform reglarly scheduled preventive maintenance, unwanted sediments and other contaminants will accumulate in the crital areas of your transformers. As a result, the performance characteristics of dielectric insulating oil will be reduced and the likelyhood of a transformer insulation failure will be greatly increased.

The GlobeCore Process of regeneraing dielectric insulating oil is able to dissolve and remove sediments at high temperatures from the transformer’s core and solid insulation. Even previously accumulated sediments may be dissolved and removed from the entire transformer.

The following table shows the limiting values of transformer oil that indicate when it is necessary to regenerate the transformer’s dielectric oil.

Performance Characteristic	Value
Acid number	>0.08 mgKOH/g of oil
Dielectric losses at 90⁰C (40 and 60 Hz)	>0.2 for power transformers and reactors with voltage more than 170 kW.
Dielectric losses at 90⁰C (40 and 60 Hz)	>0.50 for power transformers and reactors with voltage less than 170 kW.
Inhibitor content	Inhibitor additve concentration <.4%
Acidity and surface tension correlation	Acidity > 0.6 mgKOH/g of oil and surface tension <30 mN/m
Sediments	perceptible sediments
Additionally, IEC Standard 60422 recommends to regenerate oil if the performance characteristics of the oil are reduced.

Benefits of Preventive Maintenance

The degradation effects suffered by the solid insultaion found in the modern oil filled electric power transformer are irreversible. Solid insulation degradation cannot be repaired through any modern regeneration technologies on the world market today. Regeneration therefore, should be considered as a preventive mantenance procedure as opposed to a corrective maintenance procedure. The GlobeCore “Service Life Extension Program” uses advanced modern technolgy to remove moisture and contaminants that degrade the transformer’s solid insulation. It provides for the service life extension of the transformer by removing the progressive aging contaminant from the solid insulation.

GlobeCore CMM-R oil processing units

The table below shows the results of the physicochemical analysis of transformer oil that has been regenerated using the GlobeCore CMM-R oil processing units.

The Results of Physicochemical Analysis of Transformer Oil

№	Characteristic	Before regeneration	After regeneration	IEC 60296 standard
1	Physical form	Cloudy, dark brown	Pure, clear	Pure, without sediments
2	Acid number, mg KOH/g oil	0.63	0.01	0.01
3	Corrosive sulphur	+	none	none
4	Moisture content, ррm, no more than	170	5	30-40
5	Breakdown voltage, kW	11	73	30-70
6	Dielectric dissipation factor at 90ºС, %	4.0	0.001	0.005
7	Gas content, %	12	0.1	–
8	Surface tension at 25ºС, mN/m	22	45	40
9	Mechanical impurities in microns	50	0.2	–
10	Oxidation resistance test:– acid number mg of KOH/g oil	–	0.2	1.2

After regeneration, oil that has been used for many years is restored to its original new like condition and its dielectric properties are kept stable during many years of future service.

GlobeCore regeneration units substantially extend the service life of electric power transformers.

What Does “Oil Filtration” Mean?

May 30, 2015Case Studies Of Oil Reclamationdielectric oil filtration, Lubricating Oil, oil filtration, oil purification, oil reclaimer, oil reclamation, oil reclamation equipment, oil reclamation machine, oil reclamation plant, oil reclamation systems, oil reclamation unit, power transformer, reclaim oil, transformer oil reclamation, what does filtration mean, what does oil filtration mean

At first glance, the question “What is oil filtration” seems to be easy to answer. There are however, no hard and fast answers to this question because of the great amount of variety of oil found on the world oil market. If for a moment you were to put aside the broad variety of oils on the market, we can answer the question in the following way:

Oil filtration is a method of removing contaminants either in a suspended state either to protect the equipment, or to extend the service life of the oil.

Let’s discuss it in more detail.

What does filtration mean?

There are two types of oil filtration:

Primary purification; and
Secondary purification;

Primary purification is used to protect equipment. The filtering devices are mounted by the equipment producers. From a technical point of view, this type of filtration is realized with a by-pass valve that lets the oil flow past and through the valve. This device removes impurities of more than 25 microns.

This kind of filtration is called “coarse” filtration due to the size of contaminants being filtered. The primarily task of this kind of filtration is to prevent equipment damage by coarse particles. The filtering devices are mounted in the lubrication circuit of the equipment or in the delivery line that leads to the lubrication point. Sometimes they are be mounted in the return pipeline that goes from the lubrication point depending on the equipment manufacturer’s design and engineering concept.

Filters are usually made of porous materials. The internal bypass valve opens when filters become saturated with contaminants and/or when pressure exceeds preset limits. Non-filtered oil then flows out of the filter and is circulated into the equipment.

A secondary filtration is applied in order to extend the service life of oil through by purifying and restoring the oil’s performance characteristcs. Often, a secondary filtration method is called “oil purification.” The main benefit of this kind of filtration is that it extends the service life of the oil as well as the equipment. Sometimes, producers provide equipment with a built-in secondary filtration system, but often secondary filtration is considered to be an optional pice of equipment.

The following are the most widespread methods of secondary filtration:

Centrifuge filtration;
Magnetic and vacuum cleanings;
Dehydration; and
Application of filtering materials.

Secondary filtration is able to clean oil to the lowest ISO purity class standard. Even if seconday filtration systems are in place, it is not recommended to change or remove the the primary filtration system mounted by the equipment manufacturer.

GlobeCore has a wide spectrum of filtering systems designed and intended for the purification of lubricating oils and fluids. These systems provide for the service life extension of oil as well as the oil-filled equipment.

Taking into consideration the high prices for oil filled equipment and the cost of oil changes as well as possible downtimes, it is reasonable to mount GlobeCore’s secondary filtration units on your existing equipment.

Start-Up of Equipment in Poland

May 20, 2015Newscomissioning, equipment, oil reclaimer, oil reclamation, oil reclamation equipment, oil reclamation machine, oil reclamation systems, oil reclamation unit, Poland, power transformer, reclaim oil, start-up, start-up of equipment, transformer oil, transformer oil reclamation

In September 2014, GlobeCore employees started up a new CMM-10A oil purification unit in Poland. The CMM-10A is used to vacuum transformers and purify dielectric insulating oil.

The CMM-10A unit is designed and intended for heating oil used in electric power transformers, degassing of transformer oil, and transformer vacuumizing.

The main users of this kind of equipment are facilities that are engaged in mounting, repairing and servicing oil-filled, high-voltage electrical equipment.