What You Need to Know About Transformer Maintenance

Electrical transformers are one of the most expensive and important components of an electrical system. Therefore, it is necessary to have regular maintenance and checks on your transformer in order to achieve optimum performance and longer product life. If maintenance checks are routinely performed, you may not need to go into breakdown maintenance. In addition, when a transformer fails, it can be irreversibly damaged or damage the environment by creating an explosion/fire risk. Especially in critical facilities such as factories, energy facilities, petrochemicals, mining facilities, it is a necessity for the facility not to interrupt transformer maintenance.

Transformer Maintenance Controls on a Monthly Basis

  • * The oil level in the oil cap must be checked monthly to ensure that it does not fall below a fixed limit and therefore is not damaged.
    * Control to keep the breathing holes clean is important to ensure proper ventilation at all times.
    * If your electrical transformer has an oil filling bushing, monthly checks are also important in terms of filling the oil to the correct level.

Annual Transformer Maintenance Program

  • * Air fans, oil pumps and other items used to cool the transformer and control circuit should be inspected annually.
    * Be sure to clean all the passageways of your electrical transformer every year, using only a soft cotton cloth.
    * The oil condition of the transformer should be carefully examined on an annual basis. For this, take an oil sample from the relief valve and test it for moisture content (PPM) and dielectric strength (BDV). If the BDV value is low and the PPM value is high, the oil needs to be changed.
    * The health status of transformer windings is important. Both the normal resistance and the insulation (insulation) resistance of the primary-secondary windings should be measured.
    * The conversion ratio of the primary-secondary windings must be measured. This is especially important in parallel systems. Make sure there are no problems with the tap connections.
    * Make sure to clean the inside of all marshalling boxes every year. Check that the space and lighting heaters are working properly. All terminal connections of the control and relay cables should be tightened at least once a year.
    * All control switches, alarms and relays, their circuits, remote tap changer control panel, relay and control panel should be cleaned with a suitable cleaning agent.
    * Oil of tap changer contactors should be changed in high power transformers. The arc that emerges with each step change may degrade the oil over time.
    * It should be checked whether the protection systems such as differential protection relay, bulcholz relay, heat control relay, reverse current relay, earth leakage protection relay, winding short circuit protection relay, overcurrent protection relay work properly.
    * Inspect and fill all sections to see if they have the required oil level for the winding temperature gauge and oil temperature gauge.
    * Humidity is one of the biggest enemies of transformers. The silica gel used to control the humidity of the oil in the transformer should be checked.
    * Be sure to measure the resistance value of the ground connection
    * Porcelain slots should be carefully cleaned with a cotton cloth.

The maintenance of each transformer is unique to itself, and this is only possible when the expert team in the field inspects the transformer system in the field. The facility maintenance team should have the transformer systems maintained regularly and routinely and should follow this up. Otherwise, besides the loss of life and property, serious production losses or irreversible failures in transformers may be caused.