In industrial production and power systems, dry-type transformers have become one of the core equipment for power transmission and distribution due to their environmental friendliness, maintenance-free operation, and excellent fire resistance. However, during long-term operation, if scientific maintenance is lacking or external environmental factors come into play, dry-type transformers may still experience faults, ranging from affecting power supply quality to causing equipment damage or even safety accidents.
This article will delve into the six common fault types of dry-type transformers and provide targeted preventive measures to help you achieve full lifecycle management of the equipment, minimizing risks to the greatest extent!
1. Overheating Fault: The Invisible Killer of Abnormal Temperature Rise
Overheating is one of the most common faults in dry-type transformers, mainly caused by the following reasons:
Overloading: Prolonged operation under excessive load leading to winding temperature rise beyond standards;
Poor Heat Dissipation: Dust accumulation, blocked ventilation ports, or faulty cooling fans;
Poor Contact: Loose connection bolts or degradation of insulating materials, causing localized high temperatures.
Consequences: Accelerated aging of insulating materials, winding deformation, and in severe cases, short circuits or even fires.
Prevention Measures: Install intelligent temperature control systems for real-time monitoring, regularly clean heat dissipation channels, and optimize load distribution.
2. Insulation Aging: The Chronic Disease Threatening Equipment Lifespan
The insulation performance of dry-type transformers directly affects their service life, and insulation aging is often caused by the following factors:
Environmental Erosion: Moisture, dust, or corrosive gases penetrating the insulation layer;
Electrical Stress: Long-term overvoltage or partial discharge damaging the insulation structure;
Mechanical Stress: Transportation vibrations or winding loosening during operation causing insulation wear.
Consequences: Decreased insulation resistance, increased leakage current, and eventual breakdown faults.
Prevention Measures: Use high-temperature-resistant insulation materials (e.g., Class H or C), and regularly conduct dielectric loss and partial discharge tests.
3. Partial Discharge: The Hidden Electrical Corrosion Phenomenon
Partial discharge usually occurs in weak insulation areas, such as between winding turns or at core joints. Its causes include:
Manufacturing Defects: Air gaps or impurities in the insulation layer;
Voltage Fluctuations: Lightning strikes or operational overvoltages causing electric field distortion;
Insulation Moisture: High environmental humidity or condensation forming conductive paths.
Consequences: Continuous discharge gradually carbonizes insulation materials, eventually leading to short circuits.
Prevention Measures: Use vacuum impregnation processes to enhance insulation density, and install lightning arresters and overvoltage protection devices.
4. Short-Circuit Fault: The Instantaneous Power Disaster
Short-circuit faults are extremely hazardous, with common causes including:
External Factors: Lightning strikes, animal intrusion, or foreign object bridging;
Internal Factors: Insulation breakdown or winding deformation causing inter-turn short circuits.
Consequences: Short-circuit currents can reach tens of times the rated current, potentially burning out windings and causing explosions.
Prevention Measures: Configure quick-break and differential protection devices, and regularly inspect the safety of the equipment's surrounding environment.
5. Core Multi-Point Grounding: The Hard-to-Detect Eddy Current Trap
During normal operation, the core of a dry-type transformer must be single-point grounded to eliminate static electricity. If multi-point grounding occurs, it can lead to:
Circulating Current Heating: A sharp increase in core eddy current losses, causing abnormal temperature rise;
Insulation Oil Carbonization (for oil-immersed designs);
Increased Vibration and Noise.
Prevention Measures: Install core grounding current monitors and regularly inspect the insulation status of clamping parts.
6. Mechanical Damage and Loosening: The Cumulative Effect of Long-Term Operation
Under long-term vibration or improper installation, the following may occur:
Winding Deformation: Electromagnetic forces causing inter-turn insulation damage;
Loose Fasteners: Falling off of lead connectors or clamping bolts;
External Impact: Human-induced damage during equipment handling or maintenance.
Prevention Measures: Use epoxy resin casting processes to enhance structural strength and regularly perform mechanical fastening checks.
Prevention is Key: Scientific Maintenance is Crucial!
The reliability of dry-type transformers relies on a management strategy of prevention first, repair second:
1. Regular Inspections: Use infrared temperature measurement, vibration detection, and other methods to identify early signs of faults;
2. Condition Monitoring: Deploy online monitoring systems to track temperature, current, partial discharge, and other parameters in real time;
3. Professional Maintenance: Have qualified teams perform cleaning, fastening, and insulation testing;
4. Environmental Control: Ensure the equipment is installed in a dry, ventilated, and dust-free environment.
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