Types of testing
DEGASSING, REGENERATION, DRYING AND PURIFICATION OF TRANSFORMER OIL
Transformer oil is an essential component of power electrical equipment, ensuring its long-term and reliable operation. It is designed to insulate live parts and assemblies of a power transformer, dissipate heat generated during operation, and protect the insulation from moisture. Transformer oils also serve as an arc-quenching medium.
During transformer operation, the oil is exposed to various mechanical, thermal, and chemical influences, resulting in contamination and degradation of its performance properties. Traditional methods of disposing of used oils increase raw material consumption and cause environmental pollution. However, today there is an alternative solution — regeneration, which allows the reuse of used oil. Regeneration includes the following processes:
- degassing;
- purification;
- filtration;
- drying.
transformer oil drying
The process of restoring transformer oils is carried out using specialized equipment. PromStroyElectro LLC offers transformer oil purification services. During the purification process, filters and adsorbents are used.
Oil drying removes moisture that may form as a result of contact with air or other sources. Moisture can reduce the insulating properties of the oil and lead to arcing.
Methods of drying
Vacuum drying
Vacuum drying places the oil into a vacuum chamber. As the pressure decreases, moisture in the oil evaporates and is removed from the chamber.
Thermal drying
Thermal drying heats the oil to accelerate moisture evaporation. The temperature is controlled to prevent damage to the oil.
Adsorbent drying
Drying using adsorbents employs materials such as silica gel or zeolites to absorb moisture. The adsorbents are either placed in the oil or passed through it to remove moisture.
Besides drying, PromStroyElectro LLC carries out transformer oil degassing, filtration and purification. In a vacuum chamber, gases and other contaminants are extracted from preheated oil. This process restores the oil to its original state, removing mechanical impurities and recovering its functional properties.
Purification of transformer oil
During the operation of high-power transformers, it is necessary to regularly perform transformer oil purification. During operation, water, oxidation products and mechanical impurities accumulate in the oil.
Transformer oils produced through deep refining of petroleum oils using various methods. Crude oil is typically extracted from different fields, so the transformer oil obtained from it has varying physicochemical properties and hydrocarbon composition.
Methods of purification
Filtration
Filtration removes physical contaminants such as particles, dust, metal and dirt. The oil is passed through filters with different pore sizes, which retain contaminants according to their size.
Centrifugation
Centrifugation uses centrifugal force to separate contaminants from the oil. The oil is spun at high speed in a centrifuge, which forces the contaminants toward the outer wall of the chamber. The contaminants are then removed from the oil.
Washing
Washing involves rinsing the oil with a solvent or water, followed by filtration. The solvent or water helps dissolve and remove chemical contaminants, such as acids and alkalis.
Adsorption
Adsorption uses adsorbents such as alumina or activated carbon to remove chemical contaminants. The adsorbents have a large surface area that attracts and retains impurities.
In the technological operations carried out, the following sequence of actions is usually observed:
Mechanical purification
of transformer oil (removes moisture and solid contaminants from the oil)
Thermophysical purification
of transformer oil (vacuum treatment)
Physicochemical purification
of transformer oil (adsorption, coagulation)
Chemical purification
of transformer oil (if the first three methods are insufficient, this purification method involves more complex equipment and higher costs)
transformer oil degassing
Degassing removes gases from the oil, such as nitrogen, oxygen and hydrogen. These gases can reduce the dielectric strength of the oil and lead to the formation of bubbles, which may damage the insulation.
Degassing methods
Vacuum degassing
Placing the oil in a vacuum chamber and removing gases by evaporation under vacuum.
Spray degassing
Spraying the oil into a vacuum chamber to increase the surface area and accelerate gas evaporation.
Chemical degassing
Adding chemical compounds, such as calcium hydride, to bind and remove gases.
Advantages of Transformer Oil purification, drying and degassing
Reduction of the risk of arcing
Improvement of insulating properties
Increased transformer efficiency
Reduction of maintenance and repair costs
Extended transformer service life
Maintenance regularity
The frequency of oil purification, drying and degassing depends on various factors, such as transformer operating conditions, load and the level of contamination. As a rule, these procedures are recommended every 2–5 years or more often if the oil is heavily contaminated.
It is recommended to perform these procedures every 2–5 years.
Purification, drying and degassing of transformer oil are essential procedures for ensuring optimal operation and extending the service life of a transformer. Regularly performing these procedures helps maintain the oil’s insulating properties, reduce the risk of failure, and improve the reliability of power supply.
PromStroyElectro LLC performs the full range of transformer oil regeneration services using modern equipment and technologies. You can request transformer oil purification by contacting our managers.
Regularly performing these procedures helps maintain the oil’s insulating properties, reduce the risk of failure, and enhance the reliability of the power supply.
Certificates
Accreditation certificate
BY/112 2.5218 dated 14.08.2020
The Testing Laboratory of PromstroyElectro LLC complies with the requirements of GOST ISO/IEC 17025-2019 and is accredited in the scope of accreditation attached to this certificate.
SCOPE OF ACCREDITATION
Covers testing of power and measuring transformers, electric motors, surge arresters and lightning arresters, fuses, all types of switching devices, insulators, cable lines, capacitors, overhead power lines, circuit breakers, RCDs, grounding devices, and relay equipment.
CERTIFICATE
Participant in the interlaboratory proficiency testing
The testing laboratory of PromstroyElectro LLC has confirmed the high qualification of its personnel in the following areas: insulation resistance measurement, grounding resistance determination, and contact transition resistance measurement.
PARTICIPANT IN LABORATORY PROFICIENCY TESTING
The testing laboratory of PromstroyElectro LLC has confirmed the high qualification of its personnel in the following areas: loop impedance "phase-neutral", tripping current and time of RCDs, and tripping current of circuit breakers.
Certificate
The testing laboratory of PromstroyElectro LLC has confirmed the high qualification of its personnel in the field of high-voltage testing with leakage current measurement.
OUR CLIENTS
Completed projects
Minsk Republican Electric Power Enterprise «Minskenergo»
PromStroyElectro LLC performed works from August 2019 to May 2020 on the project “Power Supply of the Individual Housing Development Area on the Territory of the Former Military Camp in Maryina Gorka, Pukhovichi District (Phase I), Stage 1”.
«CITIC Construction Co., Ltd.»
LLC “SGS SopzëgasNop Co., 144” (PRC resident) contracted PromstroyElectro LLC to carry out construction and installation works on the external electricity supply network, in compliance with the technical specifications and project documentation, for the facility “High-tech full-cycle agro-industrial production in Uborki village, Dukorsky Village Council, Pukhovichi District, Minsk Region.”
During our collaboration, the company’s employees have proven themselves to be professionals committed to quality. All contractual obligations were fulfilled on time and in full. The Limited Liability Company “SITS Sopzgasvop Co., 144” regards PromstroyElectro LLC as a reliable partner.
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cost
The cost of our services is always negotiable and is calculated based on the complexity of the equipment being commissioned, the scope of required measurements, and the distance of the site from Minsk. Our company provides a free engineer visit within Minsk for an initial inspection and preparation of the estimate.
You can determine the cost of typical types of work for free and without a site visit by calculating, for example, the number of cable lines, circuit breakers, RCDs, sockets, lighting fixtures and other electrical equipment. You can do this yourself or provide us with copies of the project documentation for the facility being commissioned, or copies of EFI protocols from previous years for an existing facility. Contact us or submit a request on our website, and our specialist will call you back shortly, provide consultation, and calculate the cost of work completely free of charge. We provide a warranty of 12 to 36 months on all our work. We also guarantee a refund and correction of any deficiencies at our expense in case of claims from representatives of the State Enterprise “GosenergoGazNadzor” branches or other supervisory (or controlling) authorities.