Skilled specialists of design departments perform development of technical documentation in scope of technical or conceptual designs with regard to the manufacturer’s technological facilities and carry out supervision during transformer equipment manufacture and testing.

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Transformer and reactor design (electromagnetic calculation, thermal calculation, making of specifications, assembly drawings, and detail drawings, technical requirements to component parts and structural material, calculation of electrodynamic stability of windings).


Calculation of transformers and reactors, efficient design, determination of optimal variants.


Check of conformity of your project to the Customer’s requirements, modern market requirements; check of the design for efficiency, increase of competitive ability.


We render services for training of your specialists in transformer and reactor calculation and design methods by means of modern techniques.

  • General-purpose transformers and auxiliary transformers up to 35 kV voltage class.
  • Transformers and autotransformers up to 1800 kV voltage class.
  • Special-purpose transformers (furnace, converting, phase shifting, booster, high-frequency, impulse and traction transformers).
  • Transformers for DC lines and DC links in AC lines.
  • 6–15 kV, 4000 kVA dry fire-proof general- and special purpose transformers.
  • (SF6) Gas-insulated power transformers.
  • Shunt reactors:
    – range of 750 kV, 320 MVA single-phase oil transformers;
    – range of 330 kV, 100 MVA reactors.
  • Reactors for DC lines and DC links in AC lines.
  • Current-limiting reactors for connecting to transformer neutral and line.
  • Smoothing reactors for DC electric drive.
  • Reactors for static reactive power compensators.
Test equipment
Instrument transformers


Software for calculation of transformers


The present software is intended for carrying out (in a dialog mode) design studies, optimization of design solutions and of main dimensions, determination of technical and economic characteristics of general and special-purpose oil power transformers and autotransformers in the voltage range of 10…1200 kV, rated power at 100 kVA and above.

PRT*Design calculations of the transformer optimum construction
TOK*Calculation of current distribution in the windings during short-circuit
OST*Optimization of places for transposition in helical windings
MPOCalculation of magnetic field in windings
PBTCalculation of tank losses
POBCalculation of main and additional losses in the windings
RKZCalculation of dissipation resistances of the winding pairs
PRMCalculation of the main magnetic flux distribution in the magnetic core stacks
PIOCalculation of no-load losses and current
VLN*Calculation of impulse over voltages
COILINSLibrary of data to VLN for calculation coil-to-coil insulation safety factors
EPC*Calculation of electric field
ENDINSLibrary of data to EPC for calculation safety factors of electric strength of oil ducts in a zone of winding end
ENDINS2Library of data to EPC for calculation safety factors of electric strength of oil ducts outside the windings in a zone of end and in the centre height
MIDINSLibrary of data to EPC for calculation safety factors of electric strength of oil ducts between windings in a centre zone
TCOThermal calculation of the windings with ONAN, ONAF, OFAF, OFWF, ODWF, ODAF cooling systems
TCMThermal calculation of cooling systems (ONAN, ONAF, ODAN, OFAF, ODAF, OFAF/ODAF, OFWF/ODWF)
TRMCore thermal calculation
TEOLeads thermal calculation
PGRCalculation of permissible systematic and emergency overloads in the windings
Z0Calculation of impedances of zero-sequence of short-circuit and no-load of three-phase transformers and autotransformers
SNDCalculation of sound pressure level and sound power level
TRPCalculation of transient process in transformer

Stand-alone software’s

Mechanical calculations.

ELDINST 9Calculation of electrodynamic stability of the transformer windings at short-circuit

Insulation calculations

VLNCalculation of impulse over voltages
COILINSLibrary of data to VLN for calculation coil-to-coil insulation safety factors
EPCCalculation of electric field
ENDINSLibrary of data to EPC for calculation safety factors of electric strength of oil ducts in a zone of winding end
ENDINS2Library of data to EPC for calculation safety factors of electric strength of oil ducts outside the windings in a zone of end and in the centre height
MIDINSLibrary of data to EPC for calculation safety factors of electric strength of oil ducts between windings in a centre zone
BUSHINGLibrary of data to EPC for calculation safety factors of electric strength in insulation, surrounding the lower (oil) part of the bushing
TURNINSCalculation of interturn insulation safety factors

Software for distribution transformers.

PRTDesign calculation of the distribution transformers optimum

* – has integrated and stand-alone versions


Manufacturing facilities of JSC “VIT” permit to manufacture and repair of power and special-purpose transformers of up to 63 MVA, 150 kV

Manufacturing facilities of JSC “VIT” permit to manufacture and repair of power and special-purpose transformers of up to 63 MVA, 150 kV.

Area occupied by manufacturing zones makes more than 3000 м².

Technological process of transformer manufacture includes the following operations:

     - magnetic system manufacture;
     - reeling of winding;
     - manufacture of insulation details;
     - thermal vacuum treatment of windings and active part;
     - first, second and third assembly;
     - manufacture (welding and painting) of metalworks.

Magnetic systems

High quality si-steel with low level of magnetic losses is used for manufacture of magnetic systems of power and special-purpose transformers.

Cut si-steel (in laminations) is supplied by the Institute’s partners: ENPAY (Turkey) and LTC (Italy).

Manufacture of winding

Reeling of windings of the different structures and types is performed on winding machines permitting to reel the windings with mass starting from several kilograms up to 10 tons.

Soldering of connections is performed with silver brazing alloy and special soldering equipment.

Manufacture of insulation

Available technological equipment permits manufacturing of strips, distance spacers, yoke insulation etc.

Pressing and capacitive rings, cylinders, angle washers, details of complicated shape are supplied by the Institute’s partners: ENPAY (Turkey) and Weidmann (Switzerland).

Weidmann transformerboard is used as material for manufacture of insulation details. Use of this material provides high quality of insulating details, strengthening of thickness tolerances.

Thermal and vacuum treatment of windings and active parts

Thermal and vacuum treatment is performed in modern drying cabinets for windings and active parts made by MEIER (Germany).

Use of mentioned equipment permits to obtain residual moisture content of cellulose insulation after thermal and vacuum treatment at the level 0.2% maximum.

Technological process is completely automated. Thermal and vacuum modes are also registered.

Special measuring devices permits to estimate quantity of moisture released during drying in real time mode.

All products are filled with transformer oil meeting requirements of IEC 60296.

Filling of products is made in vacuum. Prior to the filling transformer oil is treated (filtration, additional drying, degassing) in special equipment of own manufacture (vacuum and degassing installations).


Assembly of transformers is made using mechanized racks, soldering and welding equipment, hydraulic equipment for pressing of windings, set of load lifting and special tools.

Operations of transportation of fully assembled transformers for testing are performed using electric bridge crane with load lifting capacity of 110 tons.


Manufacture (welding and painting) of large metalworks (tanks. conservators, cases etc.) is performed by outside companies according to design documentation developed in the Institute.

Quality of supplied metalworks is ensured by control on the part of employees of design and technological departments of the Institute at all stages of the product manufacturing.

High quality materials made by FADAL (Germany) quality of which is confirmed by ISO 9001 standard is used as anticorrosive protective layer.

In order to ensure required service life and attractive appearance of paint coatings coating systems meeting requirements of ISO 12944 standard are used depending on transformer operating conditions.

Color of coating can be according to the Customer’s requirements under RAL catalogue.


JSC “VIT” is accredited Certification body “VIT-SEPRO” and works in Certification system “ENERGOSERT-UKRAINE” and has accredited testing center (unique in Ukraine) for per-forming of full complex of tests of power high- and low-voltage equipments.



VIT-SEPRO certification body (CB VIT-SEPRO), accredited by the National Accreditation Agency of Ukraine (certificate of accreditation No. 1О078), has been functioning in JSC VIT for more than 25 years. 

CB VIT-SEPRO includes an accredited testing center (accreditation certificate No. 20360), the only one in Ukraine that has the technical capability and competent personnel to conduct a full set of tests for low-voltage and high-voltage power electrical equipment.


VIT-SEPRO performs work on certification in the System of certification of electrical products "ENERGOCERT-UKRAINE" for transformer, high-voltage and low-voltage power equipment, which includes:

  • transformers, reactors and tap-changers;
  • instrument transformers;
  • high-voltage, medium voltage and low-voltage switchgear;
  • preassembled transformer substations (KTP);
  • bushings and insulators;
  • fuses, surge arresters;
  • disconnectors, earthing switches, circuit breakers and load switches;
  • automatic circuit breakers and switching equipment;
  • power capacitors and capacitor units;
  • frequency converters;
  • cable, cable joints and cable fittings;
  • conductors, buslines, busbar;
  • other power equipment.

OS “VIT-SEPRO” performs work on certification in the Voluntary certification system UkrSEPRO (certificate from 01.03.2018). The product range of Certification Systems ENERGOCERT-UKRAINE and UkrSEPRO are the same.

In the field of product certification, OS VIT-SEPRO successfully cooperates with leading foreign companies (GE, ABB, Siemens, Schneider Electric, Danfoss, Tyco Electronics Raychem GmbH, etc.) and domestic companies (ZZVA, ZTR, "Tavrida Electric Ukraine Enterprise", Electrobudova Ukraine,"ABM Ampere", Electroservice, Electrosvit, Extreme Ltd, Elkor Corporation, etc.) and many other manufacturers of transformer, high-voltage and low-voltage power electrical equipment.


The object of certification of VIT-SEPRO is transformer, high-voltage and low-voltage equipment.

Certification is carried out for compliance with the requirements of regulatory documents in force in Ukraine in accor-dance with Art. 24 of the Lawа of Ukraine "On Technical Regulations and Conformity Assessmant" and approved Certification Procedure.

The procedure for certification of products in general provides for:

  • application for certification in the form ФОР-72.1-15;
  • registration, examination of the submitted documentation;
  • production audit, if provided for by the certification scheme;
  • sampling and identification of product samples for testing;
  • tests;
  • analysis of the results obtained and the decision on the possibility of issuing a certificate of conformity;
  • issuance of a certificate of conformity, entering certified products into the Registry of Systems;
  • conclusion of a license agreement;
  • technical supervision of certified products during their production, if provided for by the certification scheme.


The validity of the certificate issued by the CB VIT-SEPRO can be checked in the Register or by calling +38 (061) 284-52-16.


Clients of the certification body have the right to reclamation against the actions of the certification body in the manner outlined in the ПОР-713.1 procedure.


Certification is performed on the basis of contracts with applicants and paid for at the expense of their funds, regardless of the decisions taken on the results of the certification. In accordance with Art. 24 of the Law of Ukraine "On Technical Regulations and Conformity Assessment" for work in the field of voluntary conformity assessment contractual prices are applied.

The cost of work in generally depends on:

  • certification schemes, each of which involves a different complexity;
  • type of products, the number of declared types;
  • volume of technical requirements.


Certification body "VIT-SEPRO" provides confidentiality when using the information obtained during the work, according to the requirements of DSTU EN ISO / IEC 17065:2019.

When, according to the law or contractual obligations, VIT-SEPRO is required to announce confidential information, the customer or the interested party, if not prohibited by law, shall be notified in writing about this.


The certification body «VIT-SEPRO» has its own mark of conformity in-tended to mark the certified products in order to inform the consumer that the prod-ucts are certified in accordance with the rules of the ENERGOSERT-UKRAINE sys-tem.

The company has the right to use the conformity mark in accordance with the «Regulations on the mark of conformity in the ENERGOSERT-UKRAINE certifi-cation system» and the license agreement.



JSC VIT is accredited by the National Accreditation Agency of Ukraine (accreditation certificate No. 20360) as the Testing Center for Transformer and High-Voltage Equipment, the only one in Ukraine which has the technical ca-pability and competent personnel to conduct a full range of tests of transformer, low-voltage and high-voltage power electrotechnical equipment. The testing center works as a part of the certification body "VIT-SEPRO" (accreditation certificate No. 1О078).

The test center performs insulation tests with HV AC and HV DC voltages, such as impulse voltages (lighting, chopped, switching), environmental tests, high-current and high-power tests, mechanical tests and others.


  • high-current and high-power tests – short-time and peak withstand current tests, dynamical ability, internal-arc tests, explosion tests of measuring transformers and surge-arresters;
  • switching tests for switches and breakers;
  • environmental tests – high and low temperatures, humidity, dust, temperature changes, operation under severe-ice conditions;
  • mechanical and electrical endurance;
  • temperature-rise tests;
  • IP degree protection tests (including dust);
  • calibration and accuracy tests of instrument transformers;
  • impulse voltage tests;
  • HV AC voltage tests;
  • HV DC voltage tests.

A specific feature of climate test benches is the presence in each test chamber of high-voltage bushings for application of test voltage to the test object during climate tests.

On test benches, complex tests and studies of power equipment including equipment intended to work in tropical climates and areas of the far north, are carried out.

In the case of negative test results, recommendations may be issued for modifying the design of the tested equipment, and if the Customer is interested, the necessary scope of work can be performed at the manufacturing site of the insti-tute.

JSC “VIT” has many years of experience in testing power equipment at the request of manufacturers and importers, and conducting acceptance tests by the commissions of the holding DTEK, SE “NAEK “Energoatom”, structures of SE“ UkrENERGO ”, as well as other energy generating and grid companies.

In recent years, testing of power transformers produced by ZTR, TMC (Italy), ATEF (Azerbaijan), ELEKTROGRAD, ELIZ, Minsk Electrotechnical Plant (Republic of Belarus), measuring transformers ZZVA, vacuum switches manufactured by LS Industrial systems and LLC Electrosystems-Ukraine, AMPER, RZVA, switchgears produced by "Extreme Ltd.", "S-Manufacturing", SE Group, "Electrosvit", "Electroservice", Pluton, RZVA, reclosers LLC "Electrosvit", disconnectors manufactured by ABB (Bulgaria), LLC "KZVA", busbars "ALIT", "ZZVA", “Elox Plant” and many other products.


Clients of the testing centre have the right for reclamation against the actions of the testing centre in the manner outlined in the ПВЦ-79.1 procedure.


In order to provide high quality of performed tests the department of metrology and measuring equipment is available in the Institute. The main activities of this department are:

    • metrological service of measuring instruments;
    • metrological attestation of HV measuring instruments within the range:
            ◦ 3–800 kV direct voltage, 0.1 accuracy class;
            ◦ 3–1000 kV alternating voltage, 0.1 accuracy class;
            ◦ 3–2000 kV impulse voltage, 1.0 accuracy class.
    • metrological attestation of measuring transformers:
            ◦ 0.5–1150 kV voltage transformers, 0.1 accuracy class;
            ◦ 0.5–750 kV, I = 5–4000 A current transformers, 0.2 accuracy class.
    • attestation of HV testing equipment;
    • calibration and metrological attestation of peak voltmeters;
    • attestation of measuring diagrams of insulation parameters of solid and liquid dielectrics;
    • manufacture of d.c. and a.c. potential dividers;
    • development of measuring systems for impulse voltage up to 1000 kV based on MCF type gas-filled capacitors;
    • manufacture of extender of measuring ranges for C196 (197) kilovoltmeters of up to 100 kV;
    • manufacture of two-channel dividers for attestation of oil breakdown equipment of AIM type.


Technical diagnostics of electric equipment for service life extension

JSC "VIT" performs works on expert examination, technical diagnostics of equipment of electric stations and systems, technological equipment with voltage of up to 750 kV, tests and measurement of electric equipment.

The Testing Center got Accreditation Certificate No.20360 dated 15.05.2014 of National Accreditation Agency of Ukraine.

The Institute is the developer of OMD 0.0021757.001-2012 Organizational and methodological document "Method of performing of expert examination of the customer’s transformers" coordinated with State Service of Mines Inspectorate and Industrial Safety of Ukraine.

Expert inspection specialists were trained and attested in state company "Main training and methodological center of State Labour Service" and non-destructive control specialists were trained and attested in ACNC "Euro Standard Certification NC".

All necessary permissions for works on expert examination, technical diagnostics were obtained by the Institute from State Labour Service.

Based on performed expert examination the technical condition, requirements and terms of further safe operation of electric installations and equipment with regard to operating condition and necessity of repair, upgrading, reconstruction or decommissioning are determined.

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