The breakdown of the power transformer can result in costly repair work and also negatively impact the power infrastructure. Learning about various transformer failure causes and prevention measures should be put in place to maintain a stable and efficient operation. Here are key causes and recommended prevention methods:
Electrical Failure And Dielectric Breakdown
Short circuits, overload, and lightning surges are among the major causes of transformer failure. These faults lead to insulation breakdown, and therefore cause excess heating and failure of the device eventually. Insulation can deteriorate with time, leading to high temperature exposure.
Regular Insulation Testing: Conduct insulation resistance & polarisation index tests whereby the insulation’s health is monitored.
Install Surge Protectors: Control voltage transients by having surge arresters that will divert and then dissipate the lightning or switching transient voltage from the transformer.
Thermal Management: Optimise cooling system performance and do not overload them, so as not to heat insulation beyond the required limits.
Damage From Moisture
Moisture contamination is a major issue for oil-filled transformers. Water can reduce the dielectric strength of the insulation oil, leading to partial discharges, insulation failure, and corrosion.
Use of Dehydrating Breathers: Install silica gel breathers to reduce moisture ingress through the transformer’s conservator tank.
Regular Oil Testing: Conduct dissolved gas analysis (DGA) and moisture content testing on transformer oil to detect early signs of moisture and take corrective actions. Seal Integrity Checks: Inspect gaskets and seals regularly to ensure they are intact and replace any that are deteriorated.
Thermal Overload
When transformers exceed their capacity, they get overheated, and this accelerates the insulation ageing process and also causes winding distortion. This may also result in causing hot spots and cause winding damage if the cable is continuously overloaded.
Load Management: Check the transformer load and ensure it is not subjected to higher load levels than its maximum capabilities. Fixation of higher capacity on a regular basis could call for a transformer upgrade.
Temperature Monitoring: Use temperature sensors to keep check on the transformer oil as well as the winding temperatures. It is necessary to set alarms to inform about the temperatures which are beyond the safe limits for the system’s operation.
Cooling System Maintenance: Ensure that cooling systems, such as fans, radiators, and oil pumps are functioning properly to dissipate heat effectively.
Oil Contamination
Contaminants in the transformer oil, such as carbon particles, sludge, and gases can degrade the oil’s insulating properties. These impurities may result from oxidation or contamination through leaks.
Routine Oil Filtration: Regularly filter and replace transformer oil to remove contaminants and maintain its dielectric strength.
Dissolved Gas Analysis: It is recommended to perform this check as often as possible to assess abnormally generated gases that point towards possible failure of insulation or arcing.
Preventive Maintenance: Transformer oil should be checked visually and through chemical analysis in order to identify cases of contamination.
Mechanical Issues
Vibrations, faults and or physical impacts may lead to winding displacement, loose connection and core issues Mechanical problems. Such mechanical stress can lead to short circuits in transformer windings or overheating.
Vibration Monitoring: Install vibration sensors to detect any strange vibrations that may be be caused because of mechanical problems.
Bushing and Tap Changer Inspection: Regularly inspect bushings and tap changers for wear or damage as they are often points of failure.
Routine Maintenance Checks: Conduct periodic physical inspections of the transformer’s structure, connections, and other parts to ensure mechanical stability.
Natural Wear And Tear
Transformers have a finite service life after which its parts degrade. Stress in transformers increases with age; insulation deteriorates, structures degrade, and efficiency reduces, making the device prone to failures.
Condition Monitoring: Check the condition of the transformer regularly so that you will be in a better position to know when it needs to be replaced.
Life Extension Programs: Use refurbishment schemes such as reconditioning of oil, replacement of old parts, rewinding and re-insulation of windings to enhance the ageing transformer’s useful life.
Scheduled Replacement: Depending on the condition assessment, replace transformers which do not have much remaining useful life to avoid a failure.
Human Error
Some of the causes of transformer failure include installation mistakes, wrong maintenance, and all-round operational mistakes. Improper installation or repair may lead to lose connections or physical damage
Proper Training: It is important that technicians and operators understand the best practice in transformer installation, maintenance, and operation.
Standardised Protocols: Safeguard operating conditions against regular human mishaps to enhance maintenance and operation procedures.
Quality Assurance Checks: Ensure that you check the quality of your work as well as the maintenance work by conducting quality control and verifying in a bid to prevent failure resulting from possible mistakes.
