Tag Archives: power transformers

Mojave Heat Air Drying Unit Will Ensure Airtightness of Power Transformers in Oman

On 17 December 2015, employees of GlobeCore commissioned a new automated Mojave Heat Hot Air Drying unit in Oman.

The Mojave Heat is used for drying and cleaning the air by removing mechanical impurities. Such a need occurs during the installation and repair of power transformers at a time it is necessary to ensure the integrity and airtightness of the transformer.  The Mojave Heat is also used to restore sorbents in other fluid processing equipment.  The agricultural industry can use the Mojave Heat for drying hay, grains and other farm products.

GlobeCore produces both automated and non-automated models of the Mojave.  For the automated models, manual/mechanical controls are completely absent.  The working mode of the Mojave Heat units is set by the operator using the touch-panel. The PID-controllers ensure smooth regulation of the heater power and frequency converters exclude the overuse of the air.

The use of modern sensors and automation technology makes the drying process more energy efficient.  In addition, unit maintenance costs are reduced.

If you any questions related to the selection of the correct Mojave Heat that best meets your needs, you can always get expert advice from an engineer or manager at GlobeCore.



Selling Transformer Oil: The Right Way to Supply, Receive and Accept the Product

In any business, be it a toy store or transformer oil sales, there are many fine points to consider.  Knowing them will save you time and money.  In this article, we will look into the process of supply and receipt of transformer dielectric insulating oil.

Every sale of transformer insulating oil must be accompanied by the correct technical documentation.  The information required on the batch can be given in original certificates or in official extracts from the original documents.

Receipt and acceptance occurs before removing the oil for use from the shipping container or tank. Ooil samples must be taken and analyzed for compliance with  the product’s claimed and documented performance specifications.  Among the parameters that must be varified are:

  • dielectric strength;
  • flashpoint;
  • acidity;
  • water soluble acid and base content;
  • particulate matter; and
  • water.

An analysis of the oil’s oxidation stability and dissipation factor at 90ºС/194ºF should be performed for electric power transformers of 110kV and above.  This analysis should also include transformers of especially important facilities regardless of the voltage class or level.  If the oxidation stability analysis is to be performed after the oil leaves the shipping container, it is recommended to take samples in the presence of the oil supplier.

For the protection of your company whether buying or selling, and to facilitate arbitration in the matter, should the need arise, one of the samples should be sealed and stored.  This will provide all the parties with an used sample of the oil so that the initial oil quality may be detemined even after the oil has been used.

Samples are taken in the following cases:

  •  If supplied in rail road or truck tanks, samples are taken before draining from each tank
  •  If supplied in barrels, the number of samples is determined by the terms of supply, however, there should be at least 1 sample per 10 tons of supplied oil.

If the results of the laboratory analysis are favorable, the transformer oil is taken to the client and pumped into the buyer’s tanks.  The oil is then either stored or treated before being used in oil filled equipment like transformers and oil filled switches.  Transformer insulating oil is transferred from tanks through hoses using additional special equipment at the storage facility.

If the lab results show that the purity of the oil is not in compliance with the established standard(s), the product must be purified immediately or prior to placement in the oil filled equipment.  Failure to do so will most likely result in preamture equipment failure and unscheduled equipment down time.

GlobeCore manufactures and supplies mobile oil treatment units such as the Mobile Oil Station type CMM-M.  The GlobeCore CMM-M units are designed for degassing, removal of particulate matter and heating of dielectric insulating oils used in electric power transformers of up to 1150 kV.  The CMM-M units can be used to heat oil filled electrical systems with hot oil as well as for vacuum drying and vacuumizing of oil filled equipment.

The following advantages of the GlobeCore CMM-M units should be noted:

  • Purification of dielectric insulating oil in one cycle;
  • Significant service life extension of insultaing oil and equipment;
  • Wide range of equipment options; and
  • Simple operation and servicing.

The CMM-M units can operate in one of three modes:

  • filtration;
  • filtration with heating; and
  • thermovacuum purification and oil degassing.

Uganda Electricity Transmission Company Limited (UETCL Uganda) to cooperate with GlobeCore

Our company is well know in every continent of the globe, and now we are focusing our effort on Africa.

GlobeCore experts Stanislav Sukhar (Export manager) and Yevgeniy Svirid (Oil purification plants lead engineer) paid a visit to UETCL (Uganda Electricity Transmission Company Limited) which expressed interest in teaming up with our company. UETCL operates many remote substations with transformers which fail quite often. Unfortunately, transformer failures and resulting power outages are still a concern in Uganda. Accoring to Christopher Mutyaba, UETCL Head of Maintenance Department, reparing or replacing a transformer can take up to six months. Transformer down time is a loss of revenue and a cause for customer dissatisfaction. The Nigerian Power Holding Company, a counterpart to UETCL, which operates 18 GlobeCore 10000 l/h Mobile Oil Purification Plants, recommended to GlobeCore to UETCL Uganda to upgrade transformer oil purification plants.

Among the recent developments in GlobeCore’s oil purification plants is a system addressing the issue of excessive foaming in the vacuum chambers of the plants, which often occurs with oil and contaminated oils.

GlobeCore currently manufactures oil purification and regeneration plants with flow rates ranging from 160 to 10000 l/h. Timely oil purification and regeneration extends lifecycle of an average transformer by 25 to 30 years. It is achieved by constant monitoring of the state of oil and paper insulation with Dissolved Gas Analysis Monitors and timely application of remedial actions – oil purification or regeneration.” – says Stanislav Sukhar, GlobeCore Export Manager.

Our engineers often travel to clients to provide startup assistance and staff training. We also organize different seminars to share our experience in oil purification. The latest seminar took place in April in Kampala, capital of Uganda, at UETCL offices. It centered on benefits of transformer oil regeneration with Fuller’s Earth, environmental and operational advantages of oil regeneration over replacement with new oil.