Production of electroenergetic transformers

Decades of experience in the rehabilitation of power distribution transformers and revisions of the transformer stations resulted in the decision to launch production and sales distribution power transformers.
Manufacture of power distribution transformers consists of several steps:

• Designing
• Creating a magnetic core for ET and the tank
• Production of primary (GP) and secondary (LV) windings
• Installation (folding) of ET
• Final examination
• Technical documentation and preparation for delivery

Production of transformers is carried out in accordance with the following standard – EN 60076

Designing a new model of energy distribution transformer begins by determining the basic sizes (Power, speed ratio, electicty, loop …) and define the losses in the core and copper, that defines the class of the transformer to the losses (The class can be defined by the customer or by the objective needs of the market at the time of design).
When you have defined the initial elements enter into the design in the narrow sense, which consists of the following:
Using sophisticated software tools for the execution of the budget of the following elements ET:

• The core and yoke
• Primary (HV) windings
• Secondary (LV) windings
• The transformer dish (Dish ribs for cooling and cover the court)

Production of workshop drawings:

• Creating drawings of all the elements that are defined by measurement
• Scheme of connections within the tank (Connecting windings with control remains with the switch VN and NN Bolt)
• Arrangement of elements on the cover of the tank
• Drawings of all support elements for fixing the active part of ET

  

  

  

  

When the design is completed in the narrow sense, The production of parts of the energy distribution transformers begins. Production of parts for ET splits in two directions.

One direction is the creation (Procurement) of the magnetic core with a defined type of dynamo sheet, precisely defined dimensions, and drafting (Procurement) of the boiler vessel with cooling ribs and cover the court according to workshop drawings that are made in the design phase.

The second direction is the creation of primary (GP) and secondary (LV) windings.
Insulating materials used in preparing the windings are renowned manufacturers such as: Sovolta, Krempel, Synflex. To create a winding used specialized automated winding machines of high speed can make a larger amount of windings.

Assembly (Assembly) power transformers consists of several elements:

• Thermal treatment of primary and / or secondary windings before placing it on a pole, in order to define how to execute the thermal treatment of insulating material (If necessary).
• Setting the HV and LV windings on the pole and securing the windings and magnetic core yoke, connecting winding terminals, switch over to Bolt.
• Installing the Court, setting elements on the lid of (insulators, seals, flags …).
• Vacuum drying of the active part of the transformer – this is one of the most important elements in the assembly stage, and this process guarantees a safe and long-term exploitation of ET in normal operating conditions without the disorder. Energomont owns a vacuum dryer in which regulates the level of vacuum, temperature and all are driven on SCADA and PLC. Each processed ET possesses graphic documentation that is proof that it is fully complied with the procedures of vacuum drying technology. This document can be made available to the Contracting Authority if there is interest.
• Processing transformer oil vacuum drying with storage under controlled conditions (Pre scattering transformer oil in the Court extent tgδ oil, and only after confirming correctness there is a permit for filling the tank).
• When vacuum drying of active work is complete, the setup is done in the same court, sealing and filling the tank with oil vacuum technique that would come to the remains of air bubbles within the court after charging.

Final testing is the verification of the projected value with confirmation of functional correctness of ET, the testing consists of the following:

• Measurement of winding resistance, measurement of transformation ratio, measuring the phase shift, as well as the detection loop (winding analyzer Tettex 2293)
• Measurement of winding insulation resistance (TeraOhm 5kV meters)
• Measurement of dielectric strength of transformer oil (OTS80PB Megger)
• Tgδ measurement of transformer oil (MIDAS micro 2883)
• The work done in the testing station:
  - Experiment for idling
  - Short circuit test
  - Test with foreign voltage 2UN + 10kV
  - Inter-turn test (200Hz)
• View warming (winding analyzer Tettex 2293) – this is one of the routine tests but Energomont does this test on each new unit

Along with the complete production of transformers that is carried out there is also documentation included, technical description of details, preparation of documentation for the end user. For each individual ET Energomont has complete documentation of the interface testing, complete documentation of the drying process (diagramming records from SCADA), all performed experiments, which are in addition to the assignment of primary documents, can be placed on request. In addition to complete documentation, the end user receives a guarantee on every new ET for a period of 24 months with a service life of service and repairs on the territory of the Republic of Serbia.

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