Transformers Repair and Maintenance: Effective Processes and Best Practices

Repairing transformers involves examining, cleaning, and fixing any defects to ensure stable and safe operation, encompassing inspections and post-repair testing.

Steps in the Transformer Repair Process

The transformer repair process involves external inspections, cleaning, disconnecting power, and oil drainage. This is followed by replacing components, rewinding coils, and cooling system maintenance, ending with technical testing to ensure safety and efficiency.

Repairing transformers is a complex technical task requiring precision and expert knowledge. Initially, a thorough “transformer inspection” checks for surface damage like enclosures, oil bushings, insulators, and key components like cooling systems and oil level gauges.

To guarantee maximum safety for technicians, the transformer must be disconnected from the power source and grounded before repair. “Draining transformer oil”, especially for oil-immersed models, is crucial for accessing parts needing repair or replacement, which may include removing and repairing the core, coils, or faulty sections.

Repairs extend beyond minor fixes such as replacing insulating gaskets and sealing leaks to potentially rewinding coils or restoring cores in severe cases.

Post-repair, “technical testing” is mandatory to confirm the transformer operates safely and reliably. Critical parameters like winding ratios, insulation resistance, and oil resistivity need thorough testing.

Finally, “cooling system cleaning” is essential for smooth operation, including replenishing insulating oil if required, comprehensive external cleaning, and checking components like cooling bearings, valves, and seals to ensure optimal performance.

Maintenance of Transformers Before and After Repair

Maintenance of Transformers Before and After Repair

Transformer maintenance involves regular oil checks, gasket cleaning, soldered joint repairs, and surface insulation cleaning, critical for post-repair operation.

Maintaining transformers is key to ensuring stable and efficient electrical equipment operation. Maintenance is divided into two major phases: pre and post-repair for optimal performance quality.

Pre-repair, routine maintenance assesses the transformer’s overall condition involving:

• Technical evaluation: Analyzing technical data is essential to determine damage or wear levels, aiding effective maintenance planning.
• Transformer cleaning: Cleaning the entire surface, casing, bushings, and terminals prevents dirt and oxidation from affecting insulation.
• Oil check: For oil transformers, oil samples must be tested for contamination, moisture, and quality, ensuring insulation and cooling are optimal.
• Insulation inspection: Measuring and analyzing insulation parameters between components like high and low voltage parts to detect potential leaks or insulation decay.
• Power and grounding system inspection: Ensuring safe operation of controls, grounding, and AC/DC supplies.

Post-repair maintenance restores functionality and assures transformer safety:

• Cleaning after repair: Removing dust and metal shavings from the repair process maintains performance.
• Insulation check: Specifically important after repairing the core, cables, or insulation parts.
• Oil level and quality inspection: Ensuring high-quality oil and replenishing it with the right type if necessary.
• Temperature performance evaluation: Measuring oil and core temperatures to detect overloads or instability.
• Grounding system safety check: Confirming compliance with technical grounding standards and fastener integrity.

Regular transformer maintenance guidelines recommend at least annual or manufacturer-directed cyclical servicing. Technicians must adhere to strict safety protocols, using appropriate tools and measurement devices for accurate transformer assessment. Such diligence not only limits incidents but also extends transformer life, preventing economic losses from power outages or repair costs.

Frequency of Periodic Inspections and Maintenance

Conducting quarterly inspections and detailed semiannual maintenance of transformers ensures early detection of wear, facilitating timely repairs for steady operation.

Determining the inspection and maintenance frequency for transformers is crucial for sustaining system stability and efficiency. Routine and detailed maintenance phases every three to six months provide peak operational performance.

• Daily Checks: Daily inspection involves assessing oil levels in Magnetic Oil Gauges (MOG) on both the main and conservator tanks, preventing oil leakage risks. Monitoring silica gel for moisture absorption capacity by replacing it if it turns pink.

• Monthly Checks and Maintenance: Monthly inspections include Dissolved Gas Analysis (DGA) in oil, critical for early detection of potential issues. For 132kV transformers, perform annually, and biannually for under-132kV. Check oil levels and technical details to identify potential problems early.

• Quarterly Maintenance: Detail-oriented maintenance preserves performance and extends transformer life, involving external cleaning, mechanical checks, cooling system inspections, cables, and connections. Thorough cleaning and checks avert dirt and corrosion risks.

• In-depth Technical Maintenance: Transformers showing efficiency decline require thorough maintenance such as drying and insulation checks. These procedures typically last from one to two weeks, improving dielectric strength and moisture elimination.

Transformer repair sustains system performance and safety. Investing in this process safeguards equipment, optimizes costs, and ensures long-term operation.

Contact QuangAnhcons via hotline: +84 9 1975 8191 for expert transformer repair and maintenance services.

QuangAnhcons offers professional transformer repair, ensuring the safety and efficiency of your electrical system.