How to prevent current transformers from getting damp?
Aug 22, 2025| 1. Installation Environment Control
Site Selection Requirements
Preferably choose a dry, well-ventilated installation location. Avoid environments with humidity, corrosive gases, or dust accumulation (such as basements or near chemical plants).
If installation in a humid area is unavoidable, install a moisture-proof sealed box or use moisture-proof transformers.
Temperature and Humidity Management
Use a temperature and humidity controller to heat the interior of the terminal box to prevent condensation (but note that heating alone cannot remove moisture; other measures are required).
During the rainy season, regularly check the cable trench drainage to reduce moisture intrusion through the cables.
2. Structural Protection Measures
Sealing
Apply mortar to seal the transformer junction box, terminal box, and other areas to prevent moisture intrusion.
Oil-immersed transformers require regular inspection of the oil level and seals, and any leaks should be addressed promptly. Moisture-Proof Material Application
Place silica gel desiccant or dehumidification bags in the terminal box and replace them regularly.
For new equipment, it is recommended to use chrome-plated, rust-resistant terminal blocks to reduce contact problems caused by oxidation.
III. Operation and Maintenance Key Points
Regular Inspections
Perform insulation resistance and dielectric loss (tanδ) tests at least annually to monitor moisture trends.
Oil-immersed transformers require regular testing of the insulating oil to control the moisture content (≤20ppm).
Abnormal Handling
If the insulation resistance of the terminal screen decreases (<1000MΩ) or the tanδ exceeds the standard (>0.5%), immediately dry it using the vacuum hot oil circulation method.
Severe moisture exposure requires replacing the insulating oil or returning the device to the factory for repair.
IV. Special Scenarios
Outdoor Installation: Install a rain cover to prevent rain from directly soaking the transformer housing. In high humidity areas: Cast resin or SF6 gas insulated transformers are preferred as they have better moisture resistance.
