Consolidate Power Defenses: Practical Guide for Full-Life-Cycle Operation & Maintenance of Transformers

In the power network of factories, transformers serve as the core equipment for energy conversion and distribution. Their stable operation directly determines the continuity of production lines and the safety of the plant area. Any unplanned shutdown will not only lead to output losses, but may also trigger secondary risks such as arc burns, insulation breakdown and fires.

For frontline electrical maintenance teams, establishing a systematic and standardized equipment management mechanism is the key to shifting from "passive emergency repair" to "active prevention". This article provides a set of practical implementation frameworks from four dimensions: daily inspection, periodic maintenance, monitoring under special conditions and disposal of typical faults.

I. Daily Inspection: Capture Minor Abnormalities to Prevent Hidden Dangers in Advance

Most sudden accidents can be detected through early signs found in routine daily checks. Implementing detailed daily inspections is the most cost-effective protection measure.

1. Inspection of Insulating Medium 

Check whether the oil level of the oil conservator stays between standard scale marks. Qualified oil shall be clear and light yellow. Dark, black oil or oil with suspended impurities indicates degraded insulation performance, requiring oil sampling testing. Meanwhile, check radiators, valves and welds for oil leakage traces.

2. Verification of Operating Temperature and Heat Dissipation 

The top oil temperature shall generally be controlled below 85°C and shall not exceed 95°C at maximum. For forced air cooling transformers, verify the fans start and stop correctly and rotate in the right direction. For natural cooling transformers, regularly clean flocculent deposits and dust on heat sinks to guarantee unobstructed heat exchange channels.

3. Monitoring of Operating Acoustic Characteristics 

Under normal operating conditions, the iron core generates uniform electromagnetic "buzzing" noise during excitation. Take immediate precautions once any abnormal sounds below are detected:

• Sharp howling: Usually caused by overvoltage or harmonic distortion
• Knocking or cracking sounds: Possibly resulting from loose iron core clamps or internal discharge
• Hissing airflow sound: Mostly indicates corona discharge on bushings or high-voltage leads

4. Inspection of Lead Wires and Bushings 

Check that the surface of high and low voltage bushings is clean without tracking marks or cracks. Observe whether terminal blocks of incoming and outgoing wires show discoloration due to overheating (oxidation and blackening). Use an infrared thermometer to detect abnormal temperatures of wire clamps.

II. Periodic Maintenance: Establish a Timeline for Predictive Maintenance

The key to extending transformer service life is implementing graded maintenance strategies based on actual operating hours.

III. Key Monitoring Under Special Scenarios

Beyond routine management, enhanced monitoring under specific working conditions and weather conditions can effectively avoid extreme risks.

• After thunderstorms and heavy rains: Focus on checking the action records of lightning arresters, inspect bushings for flashover traces, and confirm intact grounding devices.
• High temperature and heavy load seasons: Shorten intervals of infrared temperature measurement. Auxiliary heat dissipation via water mist spray or axial fans can be adopted when necessary to prevent accelerated insulation aging caused by temperature rise.
• Recommissioning after long-term storage: Conduct insulation resistance test, DC resistance test and withstand voltage test before putting into operation. Complete no-load closing impulse test; no hidden faults are allowed before load operation.

IV. Identification and Standardized Disposal of Typical Faults

When abnormal alarms are triggered, rapid fault localization and correct isolation measures can greatly reduce equipment damage.

V. Mandatory Safety Rules for On-Site Operations

The bottom line of all maintenance work is to guarantee personal and equipment safety. The work permit system must be strictly implemented. Three Steps of Energy Isolation: Identify breaking points → test for zero voltage → install grounding wires. Visual Warning: Hang "No Closing, Men Working" warning tags on operating buttons and circuit breaker handles. Dual-Person Supervision Rule: Two operators must be present for supervision during high-voltage side work; single-person operation is strictly prohibited. Archival Management: Record test data and batch numbers of replaced parts in detail after each maintenance, and build full-life-cycle health archives for transformers.

Through refined inspections, scientific maintenance strategies and sharp identification of abnormal signals, electrical management staff can minimize the risk of unplanned transformer outages. This is not only essential for stable production, but also an important approach to preserve and increase the value of factory assets.