How to optimise transformer noise control?
Optimising transformer noise control is an important topic in the design and operation of power equipment, involving material selection, structural design, manufacturing process and installation and maintenance. The following are systematic optimisation strategies and technical solutions:
First, noise source analysis
1. Magnetostrictive noise: Periodic expansion and contraction vibration of iron core silicon steel sheet under alternating magnetic field (main noise source).
2. Winding vibration: electromagnetic force generated by load current leads to vibration of winding and iron core.
3. Cooling system noise: mechanical noise generated by the operation of oil pumps and fans.
4. Structural resonance: resonance amplified noise caused by vibration of the oil tank, shell and other components.
Second, the optimisation design stage
1. Iron core optimisation
Low Magnetostrictive Silicon Steel Sheet: Adopt high permeability and low magnetostrictive oriented silicon steel (e.g. laser scored silicon steel) to reduce core vibration.
Stepped Stacking Process: Slant joints or stepped stacks are used at the core joints to reduce flux distortion.
Amorphous alloy core: Amorphous alloy has a magnetostrictive coefficient of only 1/10 that of silicon steel, significantly reducing noise (but at a higher cost).
2. Winding and electromagnetic design
Optimise magnetic flux density: reasonably reduce the design magnetic density (e.g. 1.5T→1.3T) to reduce core vibration.
Balance electromagnetic force: adopt symmetrical winding structure to suppress vibration caused by transverse electromagnetic force.
Increase damping material: fill epoxy resin or elastic rubber pad between windings to absorb vibration energy.
3. Mechanical structure design
Vibration damping support: install rubber pads or spring dampers between the iron core and the oil tank to block vibration transmission.
Strengthen the rigidity of the tank: increase the thickness of the tank wall or set up reinforcement to avoid resonance amplification.
Sound insulation shell: double-layer steel plate sandwich sound insulation cotton (such as glass fibre or polyurethane foam) to reduce airborne noise.
Third, manufacturing process optimisation
1. Iron core fastening process: use full taping or gluing process to ensure that the iron core stack is tight and reduce loose vibration.
2. Winding pre-compression: Pre-pressurisation of the winding by hydraulic device to reduce loose vibration during operation.
3. Welding process: the tank welds are continuously welded to avoid local vibration amplification caused by intermittent welding.
Fourth, the cooling system noise reduction
1. low-noise fan: low-speed (<1500rpm) large-diameter fan, with wing blades, to reduce wind noise.
2. oil pump vibration reduction: oil pump installation of flexible base, the import and export use of hose connection.
3. Intelligent temperature control: start and stop the cooling equipment dynamically according to the load to reduce unnecessary mechanical noise.
Through multidisciplinary collaborative design and full life cycle management, transformer noise can be controlled within the environmental requirements while taking into account economy and reliability.