Preventive Maintenance

Preventive maintenance is the cheapest way to protect a transformer. The next cheapest option is repairs after failure, while the costliest response to transformer failure is replacement.

A power transformer is the costliest equipment in an electrical substation. As such it is desirable to perform various preventive maintenance activities to ensure it maintains a high level of performance, avoid any form of breakdown and have a long functional life.

Transformer Oil tests and analysis

Research shows that 80% of oil related failures and breakdowns are caused by contaminated oil. Preventive oil maintenance is therefore an important factor to ensure optimum equipment reliability.

To handle electrical stress, transformer oil is required to have good di-electric strength. The transformer oil, then, must be treated to remove residual water (moisture), dissolved gasses, and dangerous particles in order to slow down ageing of the transformer. To achieve all these, transformer oil filtration is required!
Here are some Oil Test we carry out:

  • Dielectric Strength or Breakdown Voltage (BDV)
  • Water Content
  • Neutralisation Value
  • Interfacial Tension
  • Colour and appearance
  • Test for Oxidation Stability
  • Specific Resistance (Resistivity)
  • Flash Point
  • Viscosity
  • Acidity
  • Dissolved Gas Analysis

Transformer Testing

Since transformers play an important role in the electrical power system it is imperative to conduct transformer testing on a regular basis. The goal of testing is to confirm the transformer’s ability to continue functioning properly and to reduce the chance of failure. Here are some tests we carry out:

  • Transformer Insulation Resistance (IR) Test
  • Polarization Index (PI) Test
  • Transformer Voltage Ratio and Magnetising Current Test
  • Magnetic Balance (HV & LV Side)
  • Short Circuit Test
  • Winding Resistance Test
  • Verification of Vector Group

Transformer Repairs

Only few transformers fail due to old age, but rather as a result of external faults, short circuit faults, insulation failure, local overheating or accessory failure.

Repairing a transformer can significantly reduce investment costs and provide a faster turnaround instead of buying a new transformer. In repairing old transformers where the manufacturer may no longer be in existence and/or the design is obsolete and a like for like new replacement cannot be obtained, there may be significant savings in infrastructure costs and civil works in using our services to bring the transformer back to operation.

Asset Management

Power transformers can be considered as one of the most significant equipment in the electricity network, thus every electric utility and other transformer owners need a transformer asset manager to help manage their transformers. IPES is experienced and poised to become this reliable, dependable, consistent and unswerving asset manager for your company.


  • a. Life-Cycle Transformer Management Programme:
    • Risk assessment of the transformer population(s) in service
    • Condition assessment of the individual transformers
    • Life-cycle decisions about the future of the transformer
  • b. Proactive Replacement or Succession Plan of Power Transformers (Particularly important for Distribution Companies)
  • c. Spare Distribution Transformers (Particularly important for Distribution Companies)
  • d. General Transformer Consultancy:
    • Third-party check during inspection and commissioning
    • Third-party check for transformer test analysis
    • Interpretation of test results and recommendations
    • Third-party check during new transformer purchase
    • Training of client’s staff on transformer diagnostic techniques that can prevent failure
    • General consultancy on anything transformer

Transformer Commissioning

After, installation of power transformer, several pre-commissioning tests are to be done before putting the transformer in service. Along with different pre-commissioning tests, different instruments associated to the transformer are also to be checked.

IPES handles all these and more


We offer Training of operators on workings and functionalities of transformers. This Trainings are handled by experienced and skilled instructors.

Hiab Crane Services

IPES also offers Hiab Crane Services for lifting of Transformers, Circuit Breakers, RMUs, Meter Panels, Transformer Oil Drums, CT&PT, Gantries, Cable Drums, Generators, and other heavy-duty equipment and machineries and transporting them from one location to the other at very competitive prices.

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