Common Problems of Transformer Cores and Solutions

The transformer is a critical device in power systems, used for voltage conversion. Among its components, the core plays a central role in determining performance, efficiency, and operational stability. However, various issues may arise during operation that affect the normal functioning of the transformer core. This article discusses common problems associated with transformer cores and provides corresponding solutions.

1. Poor Core Grounding

Description:
The core must be grounded at one point to prevent electrostatic induction from generating floating potentials, which can cause discharges. Poor or absent grounding may lead to partial discharges, damaging insulation materials and potentially causing failures.

Causes:

• Poor or broken contact at the grounding point
• High grounding resistance
• Oxidation or corrosion due to long-term operation

Solutions:

• Regularly inspect the core's grounding status to ensure reliability
• Use low-resistance materials for connections
• Clean oxidation layers and replace aged grounding components

2. Multi-point Grounding

Description:
The core should ideally have only one grounding point. If multiple grounding points exist, a closed-loop current (circulating current) can form, leading to localized overheating and possibly damaging the core or causing fires.

Causes:

• Improper installation or maintenance creating unintended grounding
• Conductive contaminants like oil residue or metal particles causing short circuits
• Aging or damaged insulation pads

Solutions:

• Monitor temperature changes using infrared imaging
• Clean oil residue and metallic impurities
• Replace aged insulation components to maintain single-point grounding

3. Abnormal Hysteresis and Eddy Current Losses

Description:
In alternating magnetic fields, hysteresis and eddy current losses occur within the core. Excessive losses can cause abnormal heating, reducing lifespan and compromising safe operation.

Causes:

• Low-quality or aged core material
• Poor insulation between laminations
• Deviation of operating frequency from design specifications

Solutions:

• Use high-quality silicon steel sheets with better magnetic properties
• Enhance inter-lamination insulation during manufacturing
• Ensure stable power frequency matching the design requirements

4. Core Loosening or Deformation

Description:
Prolonged operation or mechanical shocks may cause the core to loosen or deform, increasing noise and vibration, and affecting electromagnetic performance.

Causes:

• Improper installation or transportation vibrations
• Material fatigue or aging
• Impact from external short circuits or lightning strikes

Solutions:

• Regularly check for loose fasteners
• Reinforce mechanical support structures
• Repair or replace deformed sections

5. Core Insulation Aging

Description:
Transformer cores are coated with an insulating layer (such as oxide or varnish). Over time, this layer may age or peel off, causing short circuits between laminations and resulting in eddy currents and local overheating.

Causes:

• Prolonged high-temperature operation accelerating insulation degradation
• Moisture or chemical corrosion
• Manufacturing defects

Solutions:

• Perform regular insulation tests
• Maintain operating temperatures within acceptable limits
• Reapply insulation coatings or replace core components if necessary

Conclusion

The condition of the transformer core significantly impacts the efficiency and safety of the transformer. Regular inspections, condition monitoring, and timely maintenance are crucial for preventing core faults. By combining scientific management with technical measures, the service life of transformers can be effectively extended, ensuring the stability of the power system.