Transformer Services

Oil Sampling and Testing

Predictive maintenance management through oil sampling and physical inspection of Transformers on site. Oil testing is done through an independent laboratory based in Gauteng.

The following tests can be performed:

  • Dielectric Strength (KV)
  • Acidity (mg KOH/g)
  • Furanic Analysis Test
  • Paper insulation test, i.e. degree of polymerization
  • Moisture content (PPM)
  • Dissolved Gas Analysis
  • Polychlorinated Biphenyl (PCB)

On - Site transformer repairs

This service includes the following:

  • Repair of oil leaks
  • Oil purification
  • Regasketing
  • Repair Buchholz relays
  • Replacing of silica gel
  • Opening and inspections of transformers

Infrared Scanning ( Thermo—graphic)

Infrared images permit a visual representation of the thermal Profile of the object/s in the image. Abnormal thermal gradients or ‘ Hot Spots’ identify defects such as high resistance joints of overloading.

High Voltage Partial Discharge Detection

There are two primary causes of failure of power electrical equipment. Namely overheating or insulation breakdown. Partial discharge is both a leading cause and indicator of insulation failure. PD

Detectors are hand held indicators of the presence of PD activity. Their purpose is to advise the operator of PD activity either for Safety reasons or as an early warning to maintenance personnel that unwanted PD activity has started. The PD detector is designed to respond to one or more of the effects produced by PD.

Ultrasound Detection Technology

All forms of electrical discharge produce ultrasound. This can readily be performed to determine the type of discharge. Certain types of contact defects produce partial—arcing that is readily detected And diagnosed by ultrasound detection.

Radio Frequency ( RF Sniffer)

Radio frequency signals are also produced by electrical discharge, permitting defects to be detected with RF sniffers designed for the purpose. The instrument is configured to detect and assist the inspector to locate fast transients such as those created by arcing, corona and internal partial discharge.

Transient Earth Voltage

The PD events in switchgear have wavelengths that are similar in size to the physical size of the switchgear, which means that the PD events will travel more like microwaves than lumped circuit electrical signals. The occurrence of PD within the equipment induces a voltage on the inner surface of the earthed housing. The TEV detector is sensitive to these tell—tale voltage signals.

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