Transformers are important components of electrical power systems. They are used to step up or step down voltage levels so that electricity can be transmitted and distributed. And to ensure reliable operation, you need to maintain them so that their lifespan can be maximised.
Whether it is a single phase or 3 phase transformer, you need to ensure that regular maintenance is carried out so that potential issues can be addressed before they become major issues. Transformer failure can lead to damage to equipment, expensive downtime and interruptions to service. And by maintaining them properly, you can minimise the risk of unplanned outages and ensure that a continuous supply of electricity can be provided. The first line of defence when it comes to maintaining transformers is visually inspecting them regularly. In this stage, you need to inspect the exterior of the transformer to check if there are signs of corrosion, overheating or leaks. Sometimes there can be physical damage. You need to check if wildlife has intruded or if the insulation has been damaged. There can be loose connections. If you spot any irregularity, further investigation has to be carried out to prevent damage. Oil is used in many transformers as an insulating medium and coolant. And you have to carry out a regular analysis of oil so that the condition of the transformer can be monitored. This analysis can let you know of potential issues such as moisture ingress, contamination and degradation of insulation materials. This is done by taking samples of the transformer oil and analyse them for dissolved gas levels, acidity, moisture content etc.
Electrical testing
Is also carried out to get an idea of the condition of the transformer’s insulation, windings and other components. Some of the common electrical tests carried out are power factor testing, insulation resistance testing and turns radio testing. You can identify degradation of insulation, winding faults etc. through these tests so that you can ensure the safety and performance of the transformer. Infrared thermography is used to check whether there are hot spots or abnormal temperature gradients within. If you detect hot spots, this means, there are areas of excessive heating. This can be due to overloading, loose connection or breakdown of insulation. If you can detect these hot spots early on, you can take corrective action before it comes a serious issue.
Another critical component that is inspected is bushings
And these are what provides electrical insulation for high voltage connections. You have to inspect these regularly to check for signs of mechanical damage, deterioration and contamination. You need to check whether there are leaks, cracks or signs of partial discharge when inspecting them. The connections can then be cleaned and tightened and if there are damaged bushings, they need to be replaced immediately. A comprehensive maintenance plan has to be in place to make sure that it specifies the scope of maintenance activities such as testing, inspections and corrective action to be taken. The maintenance plan can be tailored according to the transformer requirements.
