Power Safety Quality

Transcription

1 Power Safety Quality

2 General presentation Products and services: High voltage transformers and autotransformers with powers up to 600 MVA and voltages up to 500 kv. Medium power transformers with power ratings between 10 and 63 MVA and voltages up to 110 kv. Special transformers and autotransformers for: Mobile substations, Metallurgy, Chemistry, Transport by railway, Power plants; Equipments for neutral treatment: Arc suppression coils with continuous regulating; Coils for neutral point treatment; Neutral point and utility transformers; Earthing resistors for the neutral point treatment of medium voltage networks. Diagnostic, maintenance and modernization of power transformers in the factories and at transformer site. Key information Type of enterprise: joint-stock company Commerce Registry Code: J32/16/1993 Fiscal / Unique Code: RO Registered office: 156, Stefan cel Mare Street, RO Sibiu, Romania Social capital: RON Turnover 2010: EUR 11,4 millions Total surface: sqm Employees: 132 (July 31, 2011) University graduated: 61 Main customers: TRANSELECTRICA S.A. - The national power grid company HIDROELECTRICA S.A. - The national leader in electrical energy production ELECTRICA S.A. - The electrical nationwide power distribution and supply company ENEL ALSTOM HOLCIM SIEMENS EFACEC ABB RETRASIB S.A. - Sibiu is a joint-stock company mainly specialized in manufacturing of transformers and autotransformers for generation, transport and distribution of electrical energy. On May 18, 1895, The Hermannstadter Elektrizitätswerk A.G. - Electrical Plant Sibiu is founded, whose main activity is the production of electrical energy, employing Swiss capital. In 1924 is founded The Company of Electricity Transylvania, which mainly deals with the power transport and distribution in the south of Transylvania. In 1956 begins the rehabilitation activity of the power transformers; the first one being a 20 MVA, 110/5.5 kv transformer, manufactured by VEM Germany. In April 1993, RETRASIB separates from the Ministry of the Electrical Energy and becomes a joint stock state-owned company. At this moment, S.C. RETRASIB S.A. has 546 employees.starting from 1999 RETRASIB S.A. is a full private joint-stock company. In 2008 the board of directors decides to extend the company s area of activity by creating the technological conditions in order to manufacture transformers and autotransformers of rated powers up to 600 MVA and rated voltages up to 500 kv. The manufacturing of the power transformers according to the up-to-date technical standards requires modern and clean production spaces, high performance machines tools and highly skilled workers. This is the reason why, starting from 2008, S.C. Retrasib S.A. starts the modernization works reflected on workshops and also in the manufacturing process itself. Nowadays, the company is able to manufacture any kind of equipment within the above mentioned power and voltage ranges. In 2010 RETRASIB held a share of 70% of the power transformer market in Romania. Starting from June, 2011 RETRASIB SA is listed at Bucharest Stock Exchange.

3 DESIGN The design of the transformers is performed by our sister-company Trafo Proiect SRL, using the modern and approved computer technology. Established in 2003, in Bucharest, Trafo Project provides the documentation for execution of winding, magnetic core and metal construction (general assembly, tank, etc.) and also the assistance and consultancy services for manufacture of transformers and autotransformers with rated powers up to 600 MVA and voltages up to 500 kv. The graphic design is made with 3D design programs using specialized software CAD-CATIA PLM, integrated with SMART TEAM. The drawings are accompanied by 3D models which can be accessed in the production areas. The design is parameterized so that any modification performed on a subset is automatically transmitted to the entire product. In the designing process are used the following tools and design methods: Specialized software for optimizing material consumption of the transformers component, Transient analysis software, Software to calculate losses and shortcircuit, 3D-modeling for fluid in order to identify hot spots of of the windings, FEM analysis to optimize the electrical diagram of insulation, FEM analysis to calculate losses due to the tank and system grip. In designing and production processes of the transformers are used materials and accessories produced by ABB (tap changer, RIP bushings), Qualitrol (pressure relief devices and monitoring equipment), Coiltech (coolers), Weidmann (insulation material), ASTA (insulated copper), LTC Legnano (ready cut step lap core). MAGNETIC CORE The precision of the core manufacture is a decisive factor for the later efficiency of the transformer. With accurate cutting and careful stacking of the magnetic steel low no-load loss, low no-load current, low amplitudes of the in-rush current and low noise level is obtained. Our magnetic core (two, three or five limbs) is stacked by overlapping of individual steel sheets, carlite insulated, made of grade oriented steel of 0,27 mm thickness, according to the step-lap system. The core laminations are securely held together by means of heat shrinkable polyglass tapes and tightening facilities made from anti-magnetic steel in such a way that movement of laminations during transportation and vibrations during operation are prevented.

4 WINDINGS The windings are made of coils concentrically arranged and insulated towards the core and the adjacent coils by transformerboard barriers produced by Weidman Switzerland. They are cylindrical in shape, made of conductors of high purity electrolytic copper, paper or enamel insulated. The windings are constructed to meet the requirements with regard to the voltage ratio, mechanical resistance to shortcircuit forces, permissible temperature rise and test voltages. Depending on the necessary rating and voltage of the specific application are used various winding types such as disc continuously wound type, spiral, layer type. Windings made of disc coils are preferred for high voltages. Continuous disc windings are made of several numbers of equal coils or sections connected in series and is characterized by a high mechanical stability and operational reliability. Continuous winding of the disc coils reduces the soldering points to a minimum. Manufacturing takes place on vertical and horizontal winding banks. Precise control systems provide for constant pressure and winding pull. For low voltages, the use of layer windings has proven successful. They consist of cylinder coils which are concentrically arranged one above the other and separated via axial oil ducts. The windings are pressed, dried under constant pressure, oil-impregnated, exactly measured and, if required, readjusted geometrically. After thermal and mechanical stabilization of windings, they are assembled in order to form one phase of the transformer. They are clamped between special laminated wooden plates, enabling simple installation of windings on the magnetic core limbs. INSULATION SYSTEM The insulation system in oil-immersed transformers is made of hard insulation and dielectric liquid. Hard insulation is made of concentric cylinders or barriers from special high-pressure cardboard. The dielectric liquid is usually mineral or synthetic oil. We use only high-quality, stabilized insulation produced by renown manufacturers. Adequate drying of insulation according to vapor phase system and filling the active part with oil under vacuum are the final phases determining the high dielectric, thermal and dynamic strength of the transformer.

5 TANK COOLING SYSTEM The efficient cooling system has a decisive importance for the reliability and a long service life of the transformer. Another important part of the transformer is the tank. Its role is to protect the active part and the oil. Often this assembly weighs several hundred tons. The materials employed in the tanks manufacturing process are included in the category of steels for construction. The tank is designed with reinforced plane walls to withstand full vacuum and overpressure. The required strength calculations are performed with the help of computer aided engineering work and numerical strength tests in order to assure optimal construction design, perfect safety and safe transport of the transformer to the final location. The transformers are equipped with a cooling system which can efficiently dissipate the heat emerging during operation. It is designed and tested for permanent operation with declared capacity within the limits of specified temperature rises. In our manufacturing process we use the following types of cooling methods: ONAN, ONAF, OFAF, ODAF for oil/air cooling, as well as OFWF and ODWF for oil/water cooling. The radiator batteries or oil/air and oil/water coolers are mounted on the transformer or installed separately. The corrosion protection of the tank and equipment is standardized and is defined depending on the climatic conditions where the transformer will be operating or is adapted to the special requirements of our customers. Some parts of the equipment are often coated with zinc, enabling the transformers to operate under hardest climatic conditions. The first class corrosion protection is the basis for the long life of the tank.

6 TESTING AND QUALITY ASSURANCE HIGH POWER TRANSFORMERS AND AUTOTRANSFORMERS With highly experienced and professionally trained group of engineers, RETRASIB can perform all type of tests required by international standards: routine, type and special tests. Each individual part of the transformer are subject to the mechanical and electrical inspection prior to assembling: interphase measurement of voltage ratio, measurement of resistance, insulation resistance, measurement of short circuit loss prior to drying process, supervision of drying process and transformer oil dielectric strength testing. The final testing of each transformer is carried out in our well equipped high-voltage laboratory, located near the production hall. The high voltage laboratory allows tests and trials with increased voltage and/or power of transformers and autotransformers with powers up to 600 MVA and voltages up to 500 kv. The main equipments of the high voltage laboratory is: Cascade type generator for testing up to 1000 kv AC Pulse generator for voltage testing up to 2400 kv Generator for testing of induced voltage (150Hz) Technological equipment to simulate the operating modes of operation Equipment for noise level measuring and infrared thermal imaging Measuring equipment is high precision, in class 0.1 to 0.2

7 MEDIUM POWER TRANSFORMERS SPECIAL TRANSFORMERS AND AUTOTRANSFORMERS

8 MAINTENANCE and MODERNIZATION WORKS WHERE WE ARE The first official record referring to the Sibiu area comes from 1191 mentioning the existence of the German settlers in Transylvania having its headquarters in Cibinium. In the 14th century, it was already an important trade center. In 1376, the craftsmen were divided in 19 guilds. Sibiu became the most important ethnic German city among the seven cities that gave Transylvania its German name, Siebenbürgen. In the previous years in Sibiu have invested companies from 55 countries. Only in the West Industrial Area of Sibiu 26 companies built production plants. Their activities are mainly involved in hi-tech and electrical energy industry but also in manufacturing automotive components. manufacture bearings for gearboxes for Renault, Fiat and Volkswagen brands. Also in this area developed companies such as Gühring OHG, RUD Kettenfabrik Rieger & Dietz, Phoenix Mecano from Switzerland, Italians from Bellarma, Marquardt si Harting (electronic components) or Kuhn Technology (molds and tools for automotive industry). Wenglor Sensoric Sibiu manufactures sensors for automation. Japan is represented mainly by Takata company which manufactures airbags. Also, there is Faurecia, an European manufacturer which delivers components for automotive equipments. Siemens manufactures in Sibiu electronic components and devices. The modern airport from Sibiu allows freight and passenger voyages mainly to Munich, Frankfurt, Madrid, Milano, Rome and Vienna. The German Group, Continental Automotive Systems Ltd., one of the worldwide suppliers of parts for automotive industry has in Sibiu a production and also a research center. The French from SNR Roulments

9 RETRASIB Romania Sibiu, RO 156 Stefan cel Mare Str. Tel Fax