Overhaul and Equipment Condition Monitoring of Main Transformers in Power Systems

Transformer condition maintenance is a systematic engineering effort aimed at ensuring normal and stable operation. By employing technological means to scientifically monitor transformers in operation, collecting, organizing, and analyzing data, it becomes possible to assess future operational status and equipment health, promptly detect minor faults, and enable rapid repairs. This integrated preventive and corrective approach helps reduce economic losses and supports stable economic development and public life. In addition to condition-based maintenance, periodic maintenance is also required to ensure system stability.

Significance of Transformer Maintenance and Condition Monitoring

Impact on Substation Equipment Development

The growing number of power devices and accelerating technological upgrades place higher demands on maintenance. Traditional maintenance methods are costly, prone to safety risks, and increasingly inadequate for modern grid requirements, necessitating innovation.

Improved Maintenance Efficiency

Periodic maintenance involves frequent disassembly and reassembly, which may introduce faults. Repeated power outages subject equipment to voltage surges, increasing the risk of damage. Condition monitoring reduces unnecessary outages and handling, significantly enhancing maintenance efficiency.

Enhanced Equipment Quality and Performance

As equipment performance improves and upgrade cycles shorten, traditional maintenance methods are no longer suitable. Adaptive maintenance strategies tailored to specific equipment differences are essential to ensure stable system operation.

Transformer Maintenance and Condition Monitoring

Transformer Maintenance

Maintenance is categorized into minor and major overhauls. Minor maintenance, performed at least annually, includes inspection and cleaning of vulnerable components, grounding systems, and cooling systems, along with oil sampling for testing. Major overhauls, conducted every 5–10 years, involve disassembling and inspecting windings, switches, and cores, performing insulation oil tests, replacing seals, and servicing auxiliary equipment such as coolers and control boxes.

Condition Monitoring

This primarily involves three aspects: monitoring trace gas content in insulating oil to detect incipient faults via online analysis; measuring partial discharge to evaluate insulation condition; and measuring parameters reflecting winding deformation to prevent risks from short-circuit currents and long-term mechanical stress.

Conclusion

Transformer maintenance and condition monitoring are critical to power system stability. Outdated practices should be abandoned in favor of innovative, practical diagnostic methods tailored to real-world conditions, promoting sustainable development of the power system.