Guide To Transformer Failures - Miracle Electronics

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Transformers generally require lesser care than
most other kinds of electrical equipment.
However, in case of any constructional or
operational failures in transformers, huge
problems can be created in power systems. This
is why you must be very sure and careful while
purchasing transformers. You must purchase your
electrical equipment from reputed names like
Miracle Electronics, who are known for their
standards and quality products, along with
providing the best after-sales service too.
However, even if you purchase the best
transformers made of high quality materials,
there are possibilities of failures in the
functioning. So, you must be well aware and
educated about the possible failures and
maintenance of transformers to avoid any hassles
in the future. You must be able to identify the
types of failures, causes of failures, and how
you can detect failures at the earliest. Types
of Failures There are two types of failures faced
by transformers internal and external.
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• Internal failures Internal failures are the
  failures in the core and coil of a transformer.
  These could be rupture in the winding,
  deterioration in insulating oil, grounding
  mistakes, dielectric interruption, and open
  connection of tap changer.
• External failures External failures are those
  related to the tank of a transformer. This
• could be due to leaks in the valves, gaskets and
  cords or defects in cooling fans and Buchholz
  Relay. Other reasons may be due to bushings of
  breathers, thermometers, oil level gauge and
  over pressure valves.
• Causes of Failures
• There are a lot many reasons that can cause
  transformers to fail.
• Selection issues The transformer you choose may
  not be appropriate in terms of the type of
  insulation and capacity as per the application it
  needs to be used with. Or, it could possibly be
  because of the lack of attention to the
  conditions in the place of installation. Any
  kind of temperature variations, dampness,
  dangerous gases, etc. may lead to transformer
  failure.
• Installation issues There could be a fault in
  the installation like wrong capacity and
  protection range of lightning rods, or
  inappropriate switch and relay for protection.
• Operational issues There could be loose parts
  that get heated up, oil corrosion, overload, and
  insufficient inspection and maintenance of valves
  and accessories.
• Discovery of failures
• It is logical that the earlier a problem is
  detected, the sooner it can be solved. And, to
  detect a failure at the earliest, a careful and
  detailed maintenance and inspection is required.
  Although there are certain failures that are
  sudden, and others that form slowly with time, it
  is always advisable to keep a check for any
  issues, before they become serious.
• Sudden failures An external short circuit, a
  mechanical hit, earthquakes, fires, and
  lightning are some elements that can cause sudden
  dielectric interruptions, leading to a direct
  failure.
• Slow developing failures There is a long list
  of failures that can be caused due to external
  agents and elements that do not show a sudden
  deterioration, but they slowly
• start affecting the transformers from within.
  These include

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• Dust, wind, snow and salt lead to deterioration
  of external insulation of transformers.
• Excessive load and increase in temperature
  deteriorates the insulation of a transformer
  over the course of a few years, leading to
  serious failure.
• Although transformers are designed to resist heat
  and mechanical blows, if exposed to
• frequent and intensive blows, a series of tiny
  deformations can convert into serious internal
  defects.
• Poor insulation between core sheets, or between
  the core screw and insulation pipe can
• cause short circuit in magnetic flow, producing a
  constant short circuit current flow, which in
  turn generates excessive heating up leading to
  serious defects.
• There are lots of parts in a transformer that are
  used to protect the equipment from internal
  failures. Devices that are attached directly to a
  transformer that detect failures mechanically
  include pressure relief device, pressure rise
  relay and Buchholz Relay. Other devices that are
  indirectly joined to the control cabinet that
  detect failures electrically include ground
  current relay, over-current relay, and
  differential relay.
• So, keep a check on your transformers and make
  sure to take care of its maintenance from time
  to time. Also, make sure you get your products
  from a leading manufacturer. You can get in
  touch with us to get the best-in-class power
  transformers in India.