ZTR possesses the vertically integrated production process including all operations for manufacture of the units of transformers and reactors such as magnetic cores, windings, tanks, tap changers and other units and parts, as well as assembling and testing of finished products.
Production and testing of ZTR transformers and reactors is carried out using state-of-the-art high-technological equipment of key world trademarks:
Magnetic core production
Silicon anisotropic electric steel sheets with low and very low specific losses, including laser-treated steel sheets, are used for magnetic core production.
Automatic slitting lines COMEC (France) and GEORG (Germany) with simultaneous scraping of the strip side edges by means of special tool are employed for longitudinal cutting of steel.
Magnetic system laminations are manufactured using the high-precision automatic cross-cutting lines ТUR and GEORG (Germany) with programmed control, equipped with carbide tolls, including V-notches, ensuring simultaneous stacking of magnetic system.
Lines’ technical performances and the software ensure production of the laminations of different shapes, including Step-Lap joint stacking option.
Magnetic systems of transformers rated for power up to 80 MVA and autotransformers rated for power up to 150 MVA are manufactured using automatic line for magnetic core assembling (Е-stacker), GEORG.
Automatic line manufactured by GEORG is used for production of magnetic system elements of shunt reactors.
Magnetic cores of the transformers rated for large capacity are assembled on special tilting stands ensuring possibility of production of magnetic systems having the weights up to 350 tones.
Magnetic cores weighted up to 180 tones and assembled without upper yoke are manufactured using new assembling stand of GEORG company.
Vertical strapping unit of GEORG company is employed for tightening (pressing) of magnetic system legs.
Windings of different types and designs: helical type, continuous and interlaced, including windings made of hardened transposed conductors (CTC), are made on the large-scale range of horizontal and vertical winding machines ensuring manufacture of the windings with mass capacities from a few kg up to 20 000 kg, when adjusting the conductor tension.
High quality of windings is ensured by application of special universal expandable mandrels, complex technology of axial dimension stabilization using the electric cardboard spacers and solid electric cardboard cylinders, vacuum drying of windings under set constant pressure, cyclic pressing by means of special pressing systems manufactured by Guenter Seibold, (Germany), etc.
The section with special microclimate is furnished at the production areas of assembling workshop for manufacture of windings rated for voltage class 400 кВ and above. The section is equipped with special-purpose facilities, ensuring the maintaining of optimal parameters of microclimate, such as air temperature, relative humidity, dust content in air. Besides technological equipment for winding production the section is equipped with EOT crane, air-cushion system for transportation of technological fittings, reels with and without conductors, windings and components.
Developed technologies of winding production minimize execution of brazed joints at winding conductors, provided that unavoidable structural joints are performed by silver-containing brazes with pre-treatment of brazing area.
Insulation production ensures fabrication of the whole range of insulation parts and assembly units employed for manufacture of transformers and reactors.
The base of modern technological facilities, available at the company, ensures manufacturing of pressing and capacitance rings, bars, spacers, cylinders, angle washers, yoke insulation, etc.
Parts of irregular configuration, such as pipes, elbow pieces, couplings, flanges, are fabricated by the «moulding» method. Production of wood-chip plastic material, wood-chip plastic parts as well as paper-bakelite items is also available at the factory.
Application of technologies related to utilization of the winding spacing elements calibrated by thickness as well as rigid cylinders of electric insulating cardboard allows ensuring of constant axial dimension of windings and high electrodynamic stability.
At ZTR, laminated cardboard manufactured by Weidmann and ENPAY companies is widely used as material for production of insulation parts. Application of such material ensures high quality of insulation parts, toughening of the tolerances as for thickness and shortening of technological cycles for insulation production.
CNC-equipped processing centre manufactured by Biesse Group s.p.a., provides profiled cutting of laminated cardboard resulted in obtaining the ready-made insulation parts: pressing, support and capacitance rings, stepped parts, segments, sectors of compensating insulation, etc.
SCM Group s.p.a peripheral milling machine, equipped with system of quick tool change, allows production of profiled insulation parts (bars) of laminated cardboard with improved characteristics of quality and precision. Be single-pass operation, the machine ensures processing of three workpiece surfaces as well as manufacturing of the part profile.
At realization of program aimed to the transformer design upgrading, insulation distances in active part have been reduced by means of application of labyrinth-type oil circulation within windings, resulted in significant improvement of winding cooling condition.
Spacers for labyrinth-type oil circulation as well as shaped insulation pieces of electric insulating cardboard with thickness 0,5 mm are manufactured by means of laser machine manufactured by Yueming (China).
Thermal and vacuum treatment
Thermal and vacuum treatment of transformer active parts and insulating components is carried out by means of about 150 units of equipment, including vacuum drying compartments, oil degassing plants, oil drying boilers, filter-presses, plants for oil filling under vacuum, etc.
Drying process employed at the factory ensures moisture removal up to residual water content less than 0,2 %, providing the large margin of insulation dielectric strength.
Drying is carried out in petroleum product vapors according to advanced technology, in the installations of Micafil company, (Switzerland). Such process is fully automated and stipulates recording of temperature and vacuum modes. Instrumentation ensures on-line estimation of residual moisture content in insulation.
Transformers manufactured at the factory are filled with up-to-date high-quality oils, corresponding to the requirements of IEC 60 296. At filling into the transformer, oil is additionally processed, dried and degassed by means of oil-treatment own plants and installations manufactured by Maksey company (France).
ZTR wilding production is certified for correspondence to international standard ISO 3834-2:2005.
The factory has its own welding production with complete cycle of manufacture and provides in-house needs of the tanks and other metal structures.
All rolled metal, incoming to the production, is subjected to shot-blasting for removal of surface oxides.
Laying-out of the rolled metal is carried out at thermal cutting section equipped with machines Cristal, Ukraine and Suprarex, ESAB company, Sweden, with programmed control. This ensures laying-out of materials up to 70 sheets of ferrous and stainless metal per day, with thickness between 7 and 65 mm, by making simultaneous marking and layout of the patterns for installed parts.
The parts are mechanically treated by the park of the machines, providing execution of drilling, threading, operations of turning, milling, planning, rotary-table milling, punching, bending and roll-forging.
The main welding works are carried out by means of semi-automatic arc welding machines manufactured by EWM, (Germany), in shielding gas medium.
Metal structures able to be welded at bottom position are jointed automatically by TWIN method under the flux, using gantry manufactured by ALW (France).
Quality of the welds is inspected be such procedures as ultrasonic control, fluoroscopic flaw detection, bubble-tightness method, dye penetrant flaw method, with mandatory test pressure by oil column in the assembling process.
All welding operations are carried out by staff certified according to NPAOP 0.00-1.16-96, EN 287, ISO9606.
Prior to painting, the surfaces are processed by shot-blasting method up to degree Sa 2,5–3, following the requirements of standard ISO 12944.
Painting is carried out by high-technology machines for airless, combined and pneumatic spraying, manufactured by WAGNER, KREMLIN, GRACO, SATA, in the painting chambers and painting and drying compartments provided with three-stage dry cleaning of supply and exhaust air, mechanized lifting platforms.
For the purpose of application of rust-protective coat, high-quality materials of European manufacturer – NOVATIC, Germany, are employed. Their quality is confirmed by ISO 9001.
To ensure rated service life as well as appealing appearance of external coating, the systems corresponding to the requirements of ISO 12944 are employed for corrosion categories С3, С4, С5I, С5М, depending upon operating conditions of transformers and reactors.
Coating color is performed according to the customers’ requirements, following the catalogues RAL, ANSI, MUNSELL, etc.
Internal oil-proof surfaces of the transformer metal structures are painted using high-quality oil-resistant quick-drying white-color material – Celerol primer manufacture by Mankiewicz Gebr. & Co (Germany).
Painting works are carried out by well-trained and certified staff.
The transformers are assembled on the stands equipped with mechanized lifting racks, machines for soldering and welding, hydraulic devices for winding pressing, set of lifting and special gears.
Loading and unloading operations are carried out by means of EOT and wall-bracket cranes with load capacity up to 500 tons.
Therewith, the technology of transformer movement on air cushion is employed, ensuring mobility potential and operability of performed assembling works.
Special load-lifting devices ensure execution in assembling workshops of complete control assembling of the transformer, with installation of all components (radiators, coolers, pumps, filters, fans, instrumentation, etc.).
ZTR possesses its own testing facilities ensuring performance of testing series for full range of output products in the scope stipulated by national, inter-state and international standards, including special requirements of the customers.
ZTR testing laboratory is certified as for correspondence to DSTU ISO / IEC-17025.
A lot of tests and checks of materials, components, individual parts, units and assemblies are carried out within the transformer fabrication process.
Prior to complete assembling, windings, magnetic systems are subjected to testing. Within assembling process, functional testing is performed; if applicable, determination of impulse distribution character between windings and their sections and testing of active parts for mechanical strength, as well as other kinds of tests are carried out.
All assembled transformers are subjected to routine, type, periodical and special testing.
The factory test stations and laboratories are equipped with testing and measuring instruments and devices providing performance of all required tests, including lightning and switching voltage impulse testing, short-term and long-term induced voltage testing with measurement of partial discharges, temperature rise tests, audible sound and vibration tests, mechanical tests, transformer oil analyses.
Up-to-date testing and measuring equipment and instrumentation of HAEFELY TEST AG (Switzerland), HIGHVOLT (Germany), OMICRON, EPRO (Austria), etc. is available for application.
Hardware production ensures fabrication of wide range of units and articles such as tap changers (OLTC and OCTC), transformer control cabinets, including monitoring systems, shutoff and safety valves, disc gates, fans for cooling systems and other hi-technology products.
High-precision mechanical fabrication of tap changer motor-drive parts ensures the stock of order about 50 units of modern CNC-machines.
Available universal equipment provides execution of all kinds of machining, including such processing as blanking, bending and stamping, cold-forming, grinding, turning, milling and other types of treatment.
Other kinds of production activities
The company possesses the production capacities for manufacture of castings of ferrous and nonferrous metals in die-casting tool, under pressure, according to dispensable patterns, centrifugal casting. There is a forging bay and galvanic coating section ensuring application of coats: zinc and cadmium plating with chromate treatment, nickel, chrome, tin and silver plating.