Transformer Sound Measurement to IEC 60076-10
IEC 60076-10 defines the determination of sound levels of power transformers and reactors, including the sound intensity method; IEC 60076-10-1 provides the application guidance. This guide explains how to determine a transformer's sound power level on-site using an IEC 61043 Class 1 system — the Nor150 analyser with the Nor1290 probe, which also supports ISO 9614.
Why the sound intensity method for transformers?
- Measure on-site at the substation — no reverberation room or anechoic chamber
- Rejects steady background noise and tolerates reflecting surfaces
- Resolves the characteristic 100/120 Hz hum and its harmonics with third-octave / narrowband analysis
Measurement procedure
- Define the measurement surface at the standard distance (typically 0.3 m) per IEC 60076-10
- Calibrate the IEC 61043 Class 1 system and verify the pressure-residual intensity index (PRI)
- Scan or use discrete points, capturing intensity normal to the surface
- Integrate intensity over the surface to obtain the A-weighted sound power level (LWA)
- Issue a traceable compliance report against the purchase specification or IEC 60076-10
Watch: Norsonic Smart Sound Intensity Kit (ISO 9614)