Excessive Noise In Dry Type Transformers: Causes And Solutions For Silicon Steel Vibration

Excessive noise is generated when the core of a dry-type transformer vibrates. When the silicon steel sheets experience magnetostriction, alternating magnetic fields cause the core to expand and contract. This technical guide analyzes the root causes of increased vibration and provides actionable solutions to restore optimal performance.

Causes of Silicon Steel Sheet Vibration

Increased noise levels in a cast coil transformer indicate underlying mechanical or electrical abnormalities.

• Overexcitation and High Voltage: Operating above the rated voltage increases magnetic flux density, leading to severe magnetostriction in the silicon steel.

• Loose Core Clamping Bolts: Thermal cycling loosens the clamping structure, allowing individual core laminations to vibrate independently.

• Harmonic Distortion: Non-linear loads introduce harmonic currents, which distort the magnetic field and amplify the resonant frequencies within a cast coil dry type transformer.

Step-by-Step Diagnostic and Resolution Process

Addressing vibration issues in a cast resin distribution transformer requires a systematic engineering approach to locate and fix the source.

1. Check Operating Voltage: Measure the input voltage. If it exceeds 105% of the rated limit, adjust the tap changer to reduce overexcitation.

2. Tighten Core Fasteners: Inspect the structural bolts and apply the manufacturer-specified torque to ensure the laminations are tightly compressed.

3. Install Isolation Pads: Place high-deflection vibration-absorbing pads under the transformer base to prevent the noise from transferring to the building structure.

Noise Reduction Measures for Power Systems

Selecting equipment from reputable cast resin dry type transformer manufacturers ensures tighter manufacturing tolerances. For existing installations of a cast resin type transformer, implementing structural acoustic barriers or upgrading to harmonic filters reduces sound propagation by up to 15 decibels. Regular maintenance remains the most effective strategy to prevent unexpected noise escalation in facilities.