Production
Energy of new abilities
Traditionally the advanced technology and high-level manufacturability of adopted design solutions predetermine world-wide reputation of ZTR power transformers as reliable and easy-to-operate equipment with service life being significantly longer than that the rated resource. To the present day the transformers aged nearly a half of a century, i.e. rather less if compared with the factory lifetime, are still in operation.
The main feature of ZTR technology is vertically integrated production. It means ability to respond flexibly to the market requirement, to change promptly the production schedule and to place large scope of orders at the same time. Major of components required for transformer equipment manufacturing are produced at the site. This is a grave advantage as referred to other manufacturers.
Novelty in technology
High technical and economic characteristics as well as reliability of every output product and its competitive ability in the market are in many respects determined by the level of production technology.
ZTR possersses up-to-date competitive technology (know-how) in the field of production of power transformers and reactors (controlled and shunt reactors), - from the point of incoming inspection of materials, components up to testing of the finished products.
Leading positions of ZTR production technology are ensured due to applying of the most up-dated technological processes at all stages of production; namely, the main processes are:
- Cutting of silicon transformer steel sheets (including laser processed steel) on automatic lines equipped with carbide (tungstenous) tools, assembling of magnetic cores based on Step-Lap designs;
- Application of technology of framework assembling on centering pins for manufacturing the frameworks of transformer rated for power up to 80MVA, 110 kV (core diameter max 600 mm). These ensure shortening of the framework production cycle and reduction of the transformer no-load losses owing to accurate positioning of laminations;
- Production of windings with electric hardboard spacers being milled by thickness, and drying of winding under constant pressure to ensure stabilization of winding axial dimensions and electrodynamic stability of windings;
- Vapor-phase drying of transformer and reactor insulation in oxygen-free medium to avoid premature aging;
- Production of non-controlled and controlled reactors using up-dated patent solutions;
- Introduction of production technology for tap changers type ÐÍÒÀ and ÐÍÎÀ having extended service life of the diverter switch;
- Introduction of production technology for tap changers type ÐÍÒÀ rated for voltage class 35 kV and currents up to 1250 À;
- Improvement of flange connection design (change-over to heavy-walled flanges with grooved sealing);
- Introduction of painting technology using paint materials based on epoxy and polyurethane to improve finished surface appearance and to increase life time of the coating;
- Introduction of production technology for the tank metal structures of rectangular shape.
Magnetic core production
At present time, one of the primary requirements submitted to the power transformer manufacturers is to minimize as far as possible the value of no-load losses; this requirement is resulted in absolute necessity to develop continuously the production technology as for transformer and reactor magnetic cores.
Silicon anisotropic sheet steel with low or very low specific losses (less than 1 W/kg at Ð 1,7/50), including laser-processed steel is employed at the company for production of magnetic cores.
Longitudinal cutting of steel is performed on automatic slitting line COMEC (France) with simultaneous stripping by special tool of side edges occurred during cutting process.
Manufacture of the magnetic core laminations is carried out on program-controlled high-precision automatic cross-cut lines TUR (Germany), equipped with carbide tools including V-notches. The line provides the possibility of simultaneous stacking of magnetic core sections.
Technical abilities of the lines and their software ensure realization of the most required lamination shapes including that for stacking schemes in a versions Step-Lap.
Assembling of the framework magnetic cores is performed on special tilting tables that ensure possibility to manufacture magnetic cores with mass up to 350 tons.
Winding and insulation production
Winding and insulation production is the most complicated and critical one for all the transformer manufacturers.
Manufacture of windings of different types and designs, - screw-type, continuous-type, interlacing-type, including windings of strengthen transposed wires, is carried out on the range of horizontal and vertical machines with adjustment of wire tension, providing possibility to make windings with mass from few kg up to 20 tons.
High quality of windings is ensured by usage of special universal adjustable mandrels, complex technology for stabilization of axial dimensions by employing electric hard-board spacers, solid electric cardboard cylinders, vacuum drying of windings under constant set pressure, cycle pressing, etc.
Developed technologies of winding production minimize soldering works on winding wire joints. In doing so, unavoidable structural joints are performed by silver-containing solder with pre-treatment of soldering place. Wires are soldered by overlapping method.
Insulation production ensures manufacturing of the whole range of insulation parts and assembly units employed for transformer and reactor production. Available base of modern technological equipment ensures production of pressing and capacitance rings, rods, spacers, cylinders, angle washers, yoke insulations, etc. Irregular shape parts are manufactured by molding method: pipes, elbow fitting, sleeves, flanges. At our workshop we also produce wood-base plastic laminate and parts of this material, as well as paper-bakelite articles.
Introduction of technologies related to usage of thickness-calibrated spacer elements of the windings and the solid cylinders made of electric cardboard, ensures stable axial dimension of windings.
There is under development the technology of production and application of new structural components purposed for creation of directed oil circulation between coils and providing the improved cooling conditions for windings.
Technological processes of winding and insulation production are developed on the base of results of the whole range of application-nature research works realized by the company scientific and technical sector.
Thermal vacuum treatment
Thermal vacuum treatment of the transformer active parts and insulating components is carried out using about 150 equipment units including vacuum ovens, oil degassing plants, oil drying boilers, filter presses, oil filling plants under vacuum, etc.
Insulation drying method employed at the company ensures moisture removal from the insulation up to residual moisture content less than 0,2 %, that provides large safety margin of insulation dielectric strength. Drying is carried out in Micafil plants, (Switzerland), according to advanced oil-vapor drying technology. Petroleum derivatives (oil) of European manufacturer “ARAL”, Germany, is employed as heat-transfer material. We employ fully automatic process; temperature and vacuum modes are registered as diagrams. Measuring instruments ensures on-line estimation of insulation residual moisture content.
The transformers manufactured by the company are filled with up-to-date high-quality oils corresponding to the requirements of IEC 60 296.
At filling in the transformers, oil is additionally purified, dried and degassed in oil treatment plants made in-house and by company “Maksey”, (France).
Assembling
Assembling of the transformers, considering their individual type of production, is performed on the stands equipped with mechanized lifting racks, soldering and welding apparatus, hydraulic means for winding pressing, set of special and handling fittings.
Handling (lifting) operations are performed using electric bridge and cantilever cranes with lifting capacity up to 500 tons.
The technology of the transformer shifting on the air cushion via specially coated floors ensures maneuverability and efficiency of execution of assembling procedures.
Special load lifting tool set makes possible complete verification of transformer assembling with installation of all components (radiators, coolers, pumps, filters, fans, instrumentation, monitoring devices, etc.).
Welding production
The factory has available its own welding production with complete cycle which ensures in full scope the company’s demands as for the tanks and other metal structures of any size and type version.
Blanking operations as for cutting of sheet and profile metal-roll are performed by gas- and flame-cutting automatic machines with computerized control, manufactured by ESAB.
Mechanical treatment of sections is carried out by equipment machinery, which ensures execution of drilling, threading, turning, milling, planning, rotary milling, punching, bending and expansion.
All welding works are performed by semiautomatic electric arc welding in protective gas medium (gas + argon) using welding equipment manufactured by EWM (Germany). Tightness of welds is subjected to mandatory inspections. Accuracy of assembly unit manufacturing is ensured by application of different kinds of equipment as well as by execution of mounting works with control of erection of assembly units with each other.
Prior to painting the surfaces are treated by shot-blasting method in accordance with the requirements of ISO 12944.
Painting is performed by high-technology equipment for airless and pneumatic spraying. High-quality materials of European manufacturer - "Novatic", Germany, conformed by ISO 9001, are employed for application of anticorrosive protective coat.
Color of coating can be provided in accordance with the requirement of the Customer as for RAL catalogue.
Internal oil-resistant surfaces of metal structures are paint with qualitative resistive quick-drying material of white color – primer Celerol, manufactured by Monkiewicz, Germany.
We have mastered production of metal structures of rectangular shape tanks, which ensures manufacturability and specialization of workplaces to facilitate steady raising of the rate of production.
All welding operations are carried out by qualified staff.
Testing
The factory has available inherent testing base ensuring performance of test complex for total range of output products in the scope as specified by national, interstate and international standards as well as particular requirements of the Customers.
Within transformer manufacturing, a lot of tests and inspections is carried out for materials, components, individual parts and assembly units. Test scope and procedures are established by quality control system valid at the factory. Prior to complete mounting, windings and magnetic cores are tested separately. If necessary, operational tests, determination of impulse voltage distribution between windings and their sections, mechanical strength test for active parts, etc. are carried out within assembling process.
Each assembled transformer is subjected to routine and special tests; the main and the check units are subjected to type and periodical tests. Concurrently measurement of some parameters required for transformer estimation at site mounting and commissioning stage are carried out. The factory test fields and laboratories are equipped with testing and measuring facilities and instruments ensuring performance of all necessary test, including lightning and switching impulse tests, short-term and long-term induced voltage test with partial discharge measurement, temperature rise test, sound level measurement, mechanical tests, transformer oil testing. Up-to-date test and measurement equipment and instruments of well-known manufacturers HAEFELY TEST AG, Switzerland, HIGHVOLT, Germany, OMICRON, EPRO, Austria, etc., are currently introduced and operated. In accordance with contract requirement other kinds of test are also can be performed.
Based on the Customer request all tests are witnessed by his authorized inspector, to be sure in completely accurate correspondence to the Customer requirements.
Available test equipment as well as qualification of test staff ensures possibility to perform all tests on high level and in full correspondence with national and international standards.
Hardware production
Hardware production includes manufacture of wide range of parts and units:
- Tap changers (TC) of series ÐÍÒÀ, ÐÍÎÀ, ÏÒÐ, ÏÒË, ÏË, Ï6 for transformers.
- Manual drives, drives type ÏÄÏ (4,5,6) for above TC.
- Transformer control cabinets including that with monitoring systems.
- Shutoff and safety valves.
- Disc gates Dy50 … Dy200.
- Fans for cooling system and other advanced technology products.
All assembling and testing operations are performed on special technological stands.
High-accuracy mechanical production of tap changer drive parts ensures by range of advanced computerized machines, about 50 units, manufactured in Germany, Czechia, South Korea, Taiwan, Russia and Ukraine: capstan including that with drive tool, automatic bar-stock machines, boring mills, vertical-spindle knee-and-column-type milling machines, boring machining centers, boring mills, keyseaters.
Name-plates of the transformer equipment are made by laser etching method on stainless steel, by brass engraving with subsequent nickel-chrome plating, or by photochemical method.
It is also available a sufficient number of universal equipment purposed for all kinds of metal processing including blanking, bending and stamping, cold-forming, grinding, turning, milling and other types of treatments.
The company has available production capacities for manufacturing of ferrous and non-ferrous metal casting in to metal molds under pressure, based on consumable patterns, spun casting. There are forge section as well as electroplating sector providing possibility to apply coatings: zinc and cadmium with chromium-plating, nickel, chrome, tin and silver plating.
