SMIT-Transformatoren

Introduction

Since its beginning in 1913, SMIT has played an active role in the development and manufacturing of large power transformers and reactors. Ratings up to 1000 MVA with voltages up to 525 kV and insulation levels of 1800 kV BIL, can be manufactured for SMIT customers.

The SMIT manufacturing facilities are located in Nijmegen in the eastern part of the Netherlands. The plant is located near the river Waal providing easy access to the Rotterdam and Antwerp harbours for shipments throughout the world.

A modern production location where large power transformers are sold world wide, calculated, designed, manufactured and tested.
The engineering department keeps pushing the aforementioned boundaries to the limit, using advanced calculation programs and 3-D design modules for a good and unique product.
As soon as you enter the production halls, final assembly department and testing laboratory, you realise what they mean when they say ‘large’ transformers. Composure and discipline also reign here, hearing the sound of the vacuum pumps working day and night to prepare a transformer for the oil filling process.

The Lean Manufacturing principles are propagated and employees are trained and encouraged to strive for continuous improvement. The purpose of this is to achieve a shorter throughput time, while not affecting the quality level.

Over the years, SMIT has earned an excellent reputation with leading customer’s world-wide. In the Netherlands they include well-known names such as TenneT, NUON, ENECO, Delta and Essent. SMIT also has a large number of customers in Western Europe, such as EDF (France), RWE, E.ON (both Germany), Statnett (Norway), Fingrid (Finland), National Grid Company (UK), Scottish Power (Scotland) and Iberdrola (Spain). In the early eighties SMIT made its first shipments to the USA. By now, hundreds of transformers form part of the electricity grids in the USA. American customers include Dominion Virginia Power, Exelon, Florida Power & Light, PEPCO, PECO and ITC.

In our final assembly department a very smooth concrete surface has been put down, which stretches from here well into the modern high-voltage laboratory, where the final testing is done before the transformer can be transferred.

This concrete floor is the foundation for the new air cushion transport system on which transformers weighting up to half a million kilos (500.000 kg) can be transported in a matter of minutes with the help of a simple joystick. It goes without saying that this improves efficiency enormously.

Design

SMIT developed as an independent transformer manufacturer in the stimulating and very demanding markets in Europe and the United States. By utilising its own design capabilities and manufacturing know-how, SMIT has achieved recognition for being able to meet even the most stringent requirements of national and international standards for product quality and reliability.

This tradition of working for international markets has developed SMIT as a flexible and consistent supplier of the most reliable large power transformers available today.

Engineering

SMIT has an ongoing engineering evaluation process for constantly improving and upgrading its design programs. SMIT developed programs for electrical stresses (insulation clearances), short circuit withstand capabilities (mechanical stresses), stray-losses (field plotting techniques), etc., to perfect and expand its knowledge of transformer design criteria.
Another advancement has been achieved with a SMIT developed program for the digital registration of lightning impulses across the various parts of the windings.

Engineering excellence achieved by SMIT design engineers address many critical areas of transformers construction. Two of those critical areas are:

• Mechanical clamping of the windings with a unique ‘Independent Coil Clamping Structure’.

• Highly efficient, low loss transformers through the control of stray-losses.

The advantages of the independent coil clamping construction are:

• Mechanical forces contained in the coil clamping are not transmitted to the core, resulting in lower noise level.

• The coil clamping can be made stronger, but smaller and simpler which reduces the stray-losses.

• Greater short circuit withstand capabilities are achieved.

• Manufacturing tolerances are easier to achieve and maintain through the assembly process.

Efficiency and low loss designs are achieved through:

• Advanced calculation programs that pinpoint critical areas.

• Utilisation of transposed cable for the majority of winding designs.

• Stray loss and field plotting techniques determine optimum shielding of the required areas.

• Unique winding designs engineered to meet the required performance levels.

Tests

Completed units will undergo electrical tests in accordance with the latest ANSI, IEEE, IEC and other recognised Standards, including NIST technical note 1204.
These tests are performed in a well-equipped own high voltage laboratory.

Standard tests include:

• Resistance measurements

• Polarity and phase-relation tests

• Impedance voltage and load loss measurements

• No-load losses and excitation current measurements

• Low frequency dielectric tests with applied and induced voltages

In addition to the standard tests, design and other tests can be completed:

• Temperature rise tests

• Dielectric tests with lightning and switching impulse voltages

• Audible sound level measurements

• Partial discharge, both microvolts of pico coulombs

Transport

SMIT transport department is responsible for the transport, erection, installation and commissioning of our power transformers. In addition it can also provide a crew of well-trained and internationally experienced technicians as well as mobile equipment trailers with oil purification system and vacuum pump.

Service

SMIT has integrated into its organisation a service department that is responsible for repair, maintenance and service for all make of transformers. This service is on stand-by 24 hours a day.