Service Life Extension of High Voltage Equipment

GlobeCore transformer oil purification plants are designed to restore the properties of transformer oils and extend the service life of the oil filled equipment.

At the beginning of the 21st century, the main task of the electric power industry was to maintain electric equipment, the expected service life of which had expired.  This issue was at and remains at the top of problems faced by the electric power industry because of the limited financial resources to buy new equipment.

The progress of the electric power industry in the world’s industrialized countries reached its highest peak in 1970s and 1980s.  In the USA it was reached in 1974 when transformer capacity was increased to 180 gigavolts and amps.  By this time, the typical electrical equipment had served more than 40 years, exceeding its expected service life by more than 15 years on average.

The following is the list of common reasons for transformer breakdownsand failures:

  • deterioration of equipment, caused by some disadvantages that speed up the aging process;
  • accelerated aging of associated parts (inputs, parts of a cooling system);
  • dynamic instability of windings inthe case of short circuits;
  • damages of the main and longitudinal insulation usually caused by moisturization, contamination, and long term use without regeneration and purification; and
  • irreversible destruction of cellulose through neglect.

It should be mentioned that more than 80% of breakdowns may be avoided if timely preventive maintenance is performed on a scheduled basis in conjunction with an comprehensive oil analysis program.

The Concept of  Service Life Extension for your Electric Power Equipment

Maintenance of transformers, the expected service life of which has expired, is possible with a good preventive and corrective maintenance program.

The first stage consists in the evaluation of the actual condition of the equipment. It allows the equipment owners to determine whether a service life extension program is reasonable on a case by case basis.  If there are no irreparable damages that require the main components to be changed, then the measures to extend the service life  of a transformer should be taken.

The following is the detailed list of  work performed:

  • to remove the potential defects that directly affect the equipments reliability and accelerates the aging process;
  • remove moisture, gasses, mechanical impurities and the products of aging, including those, being absorbed by the cellulose insulation;
  • improve potentially unreliable parts in order to hamper the process of aging;
  • reduce operational costs through the introduction of a monitoring system or optimization of a cooling system; and
  • regenerate/reclaim used transformer oil currently in operation in the transformer.

You may have noticed that the majority of defects are connected with reversible changes in the insulating system caused by moisture, contamination by mechanical impurities, and gases.  In fact, the service life of oil filled equipment may be extended by removal of moisture and water, removal of mechanical impurities, degassing and complete oil restoration/reclamation.

Additionally, these measures are considered to be the most effective ones.  GlobeCore  offers a wide range of mobile transformer oil purification plants.  They are designed to restore oils to the like new condition that have minor deviations from the rated values as well as waste oils unsuitable for further use.  On one hand, such an approach provides for the service life extension of high voltage equipment by improving the condition of the equipment’s insulating system.  On the other hand, it helps to save money on new oil purchases and by avoiding waste oil disposal costs.  Some mobile oil plants, in particular the GlobeCore CMM-R line, are designed to process oil even on energized transformers.  Proper and timely preventive maintenance will reduce equipment downtime and unscheduled repairs.

обновлено: August 27, 2015 автором: dannik