How Does Dry Type Distribution Transformer Noise Come From?

Dry-type distribution transformers generate noise during operation, which can gradually degrade performance and efficiency if unaddressed. Understanding the root causes of noise is key to targeted mitigation—below is a detailed breakdown of the three core sources, with technical insights tailored to CHH Power’s product design.

Contents hide

1 1. Noise from Silicon Steel Sheet Magnetostriction

2 2. Core Noise from Electromagnetic Action

3 3. Winding Vibration Noise from Leakage Flux

4 OUR CERTIFICATE

5 OUR PROJECTS

1. Noise from Silicon Steel Sheet Magnetostriction

This is the primary noise source for dry-type transformers, arising from the inherent physical property of silicon steel sheets under magnetization.

Core Principle: When the transformer core is energized, silicon steel sheets expand along the magnetic field direction and contract perpendicular to it. This periodic deformation (magnetostriction) causes the core to vibrate in sync with the excitation frequency.
Noise Characteristics: The vibration period of magnetostriction is half the power frequency, so the fundamental noise frequency is twice the power frequency (e.g., 100Hz for 50Hz power grids). Due to the non-linearity of magnetostriction and uneven magnetic flux paths in the core, high-order harmonic noise (200Hz, 300Hz, etc.) is also generated.

2. Core Noise from Electromagnetic Action

This secondary noise source stems from electromagnetic forces between core components, with minimal impact in modern designs.

Core Principle: Magnetic flux leakage creates electromagnetic attraction between silicon steel sheet joints and laminations, triggering slight core vibration.
Practical Significance: CHH Power adopts advanced core stacking techniques (e.g., staggered seam lamination, tight clamping) to minimize this vibration. The resulting noise is far weaker than that from magnetostriction, so it is typically negligible in routine operation.

3. Winding Vibration Noise from Leakage Flux

Noise caused by winding vibration, whose intensity is closely related to load current and magnetic flux density.

Core Principle: Leakage flux generated by the winding’s load current exerts electromagnetic forces on the windings, leading to vibration.
Noise Characteristics: When the transformer’s rated magnetic flux density is 1.5–1.8T, this vibration is minor compared to magnetostriction-induced core noise. However, noise from leakage flux is proportional to the square of the load current—if the rated magnetic flux density is reduced to below 1.4T, winding vibration noise becomes comparable to magnetostriction-induced core noise.