IEC 60329: Transformer and Reactor Sound Level Measurement — The Basis for Substation Noise Control

Where Does the Substation “Hum” Come From? Magnetostriction in the Transformer Core

IEC 60329:1985 specifies transformer and reactor sound level measurement. Transformer noise primarily originates from core lamination magnetostriction — silicon steel dimensions cyclically change at 100Hz fundamental under 50Hz magnetization. Noise is proportional to B² — higher design flux density means a more compact but louder transformer.

TNLab — Transformer noise is a magnetostriction “byproduct” — reducing design flux density lowers noise but increases core volume and cost.