Supply and Installation of Transformers

Analyzing oil is a unique way of identifying problems occurring within a transformer
By identifying and analyzing gas found within transformer oil the condition of the transformer can be monitored
Samples are sent to independent laboratories
Samples should be taken regularly and a record kept
Recommendations should be followed

Transformer services offered

Water content
Through the breather
Leaks i.e. bad gasketing, cracked insulation
Paper degradation
Oil degradation
Once the paper has been degraded it can never be returned to original condition
Dielectric strength
Tests the insulating oils ability to withstand electrical stress without failure
Contaminants such as water, sediment and conducting particles reduce dielectric strength of insulating oil
Two probes are immersed in the insulating oil. Dielectric strength is at a predetermined distance which decreases as the contaminants increase
Dissolved Gas Analysis (DGA)
Insulating oil under abnormal electrical & thermal stresses breakdown to liberate small quantities of gas
DGA’s give advanced warning of developing faults

A sudden large release of gas will not dissolve in gas and will result in the Buccholtz Relay being activated
Acidity or Neutralization Number (NN)
Acids in oil originate from oil decomposition/oxidation
Can also come from external sources such as atmospheric contamination
Acids are detrimental to the insulation and can cause corrosion inside the tank
An increase in the acidity is an indication of the rate of deterioration of the oil
Sludge is an inevitable by-product of a acid situation which is neglected
Polychlorinated Biphenyl (PCB)
PCB’s is a synthetic transformer insulating fluid that has found it’s way into mineral insulating oil via cross contamination
The test determine chlorine in the oil as all PCB’s contain some amount of oil
PCB’s are very stable and the degradation process is very slow and therefore harmful to the environment

Buchholtz relay activates when large volumes are detected in the transformer
Temperature gauge activates when the temperature of the transformer reaches 80°C
Transformer breather is filled with Condis Crystals which is deep blue in colour. The crystals change to a pale white colour as atmospheric moisture passes through the breather.