Common Faults of Dry-Type Transformers and Their Solutions

As an important electrical device, dry-type transformers play a crucial role in modern power systems. Their main function is to adjust the voltage levels of electrical energy to meet the needs of different users. However, various faults may occur during the operation of dry-type transformers, which not only affect the normal operation of the equipment but may also pose serious risks to the safety and stability of the entire power system. Therefore, understanding the common faults of dry-type transformers and their solutions is key to ensuring their safe and efficient operation.

dry-type-transformer

Structure and Working Principle of Dry-Type Transformers

Dry-type transformers mainly consist of a core, windings, insulating materials, and a cooling system. Their working principle is based on the phenomenon of electromagnetic induction. When alternating current flows through the windings, an alternating magnetic field is generated within the core, which induces electromotive force in another winding, thus achieving voltage transformation. Since dry-type transformers do not use oil as an insulating and cooling medium, they have significant advantages in environmental adaptability and safety.

Common Faults and Their Impacts

1. Insulation Faults

   Deterioration of insulating materials is one of the most common faults in dry-type transformers. Prolonged exposure to high temperatures, humidity, and contaminants can lead to aging or damage of the insulating materials. This may cause short circuits between windings or between the windings and the core, resulting in transformer damage and even more severe safety incidents.

2. Overload Conditions

   In power systems, if dry-type transformers are in a prolonged state of overload, it can lead to increased temperatures, premature aging of the winding insulation materials, and in extreme cases, may cause fires. Overload faults are usually caused by unbalanced loads or unreasonable system designs.

3. Cooling Failures

   Dry-type transformers typically rely on air cooling. If there are issues with the cooling system, such as fan failure or blocked cooling passages, it can result in excessive transformer temperatures, affecting operational performance and potentially leading to equipment damage.

4. Connection Failures

   The connection points of dry-type transformers, such as terminals and plugs, are prone to corrosion or loosening. This can lead to poor contact, increased contact resistance, and subsequently cause heating and reduced transformer efficiency.

5. Electromagnetic Interference

   During operation, dry-type transformers may be subjected to external electromagnetic interference, which can decrease the operational stability of the transformer, affect power quality, and generate harmonics.

Dry-type transformers 

Fault Detection and Diagnosis

Regular detection and diagnosis of various faults in dry-type transformers are essential for ensuring their safe operation. Common detection methods include:

1. Temperature Monitoring

   Using thermal imaging devices to regularly monitor the temperature changes of the transformer to promptly identify overheating.

2. Insulation Resistance Testing

   Measuring the insulation resistance value between the windings and the ground using insulation resistance testers to assess insulation performance.

3. Current Load Testing

   Monitoring load current to ensure the transformer operates within the rated load range and analyzing load imbalance situations.

4. Vibration Analysis

   Conducting vibration monitoring of the transformer’s operating state to identify mechanical issues.

5. Electrical Testing

   Utilizing transformer testing equipment to conduct a comprehensive assessment of the transformer’s electrical performance, including testing parameters such as transformation ratio and short-circuit impedance.

 Fault Handling and Prevention

1. Regular Maintenance

   To reduce the occurrence of equipment faults, regular maintenance is essential. This includes periodic inspections and replacements of insulating materials, cleaning cooling passages and ventilation systems, and ensuring the transformer is in good operating condition.

2. Efficient Cooling System

   Ensuring the high efficiency of the cooling system for dry-type transformers by equipping necessary cooling devices, such as fans and heat sinks, and installing temperature alarm systems to address abnormal temperatures promptly.

3. Enhanced Insulation Protection

   Selecting high-performance insulating materials and conducting regular insulation testing to identify potential insulation issues early and prevent faults.

4. Load Management

   Ensuring a reasonable distribution of loads on dry-type transformers to avoid prolonged operation in an overloaded state and regularly analyzing load conditions.

5. Employee Training

   Providing professional training for maintenance personnel to continuously enhance their capabilities in handling and maintaining dry-type transformer faults, ensuring a swift and effective response when issues arise.

Dry-type transformers play an important role in power systems, and their faults not only affect operational efficiency but may also pose threats to personnel and equipment safety. By identifying and addressing common faults, and implementing effective monitoring and maintenance of transformers, their operational stability and safety can be significantly improved. Only by strengthening the research and practice of dry-type transformers can their application value in power systems be further enhanced, contributing to the development of modern power.