What measures can be taken to prevent excessive temperature rise in current transformers?
Apr 13, 2026| I. Reasonable Selection and Design Matching
1. Select High-Current Adaptable Transformers
For high-current scenarios such as 110kV/220kV, products with rated current covering actual operating conditions (e.g., 0~3000A) should be selected to avoid short-term temperature rises to 70–80℃ due to current exceeding limits.
2. Optimize Secondary Winding Design
Adopting redundant wire diameters (e.g., secondary copper wire current carrying capacity of 4mm² or more) and grouping + double-layer winding technology reduces conductor internal resistance, reducing heat generation at the source.
3. Select Low-Temperature Rise Technology Products
New power transformers, through technologies such as zoned potting (thermal conductivity twice that of traditional epoxy resin) and unsaturated magnetic core control, can control temperature rise to ≤35K, significantly better than traditional products.
II. Standardized Installation and Connection Process
1. Ensure Good Contact of Primary Connectors
Use a torque wrench to tighten bolts according to standards during installation to prevent increased contact resistance due to insufficient or excessive pressure; contact surfaces should be clean and coated with conductive paste.
2. Prevent Open Circuits in Secondary Circuits
Open circuit operation on the secondary side is strictly prohibited; a closed circuit must be formed to prevent excessive eddy current losses caused by deep core saturation.
3. Achieve Reliable Single-Point Grounding
The S2 terminal on the secondary side should be grounded at a single point only in the control room or terminal box to avoid circulating current interference caused by multiple grounding points.
III. Improve Heat Dissipation Conditions
1. Optimize Internal Heat Dissipation Structure
Use thermally conductive adhesive to encapsulate the magnetic core and secondary windings in sections to accelerate internal heat dissipation; abandon traditional single-sided winding and use double-layer uniform winding to avoid heat accumulation.
2. Enhance External Ventilation and Cooling
Install forced ventilation fans inside the switchgear or set up independent heat dissipation channels; during high-temperature seasons, a backup cooling device can be activated to reduce the impact of ambient temperature rise.
3. Avoid Heat Accumulation Layout
Sufficient heat dissipation space should be left around the instrument transformer, avoiding compact placement with other heat-generating components to reduce the cumulative heat effect.
IV. Operation Monitoring and Preventive Maintenance
1. Regularly Conduct Infrared Thermometer Measurement
Newly commissioned equipment should undergo its first accurate temperature measurement within 24 hours of energization and within one week. Subsequent periodic testing should be performed to promptly identify potential hazards such as loose connections and internal defects.
2. Monitor Load Change Trends
Avoid prolonged overload operation. Early warning should be issued when the load approaches the rated value, and partial load transfer should be implemented if necessary.
3. Regularly Check Insulation Condition
Measure the insulation resistance between the primary and secondary windings and ground. The resistance value should not be lower than 1000MΩ and should not show a significant decreasing trend.
