IEC 60076-10:2016

FOREWORD
INTRODUCTION
1 Scope
2 Normative references
3 Terms and definitions
4 Sound power for different loading conditions
5 Sound level measurement specification
6 Instrumentation, calibration and accuracy
7 Principal radiating surface
8 Prescribed contour
9 Microphone positions
10 Calculation of the measurement surface area
11 Sound measurement
12 Determination of sound power level by calculation
13 Logarithmic addition and subtraction of individual
   sound levels
14 Far-field calculations for distances larger than 30 m
15 Presentation of results
Annex A (informative) - Narrow-band and time-synchronous
        measurements
Annex B (informative) - Typical report of sound level
        determination
Bibliography

IEC 60076-10:2016 defines sound pressure and sound intensity measurement methods from which sound power levels of transformers, reactors and their associated cooling devices are determined. The methods are applicable to transformers, reactors and their cooling devices - either fitted to or separate from the transformer - as covered by the IEC 60076 and IEC 61378 series. This standard is primarily intended to apply to measurements made at the factory. Conditions on-site can be very different because of the proximity of objects, including other transformers. Nevertheless, this standard is applied to the extent possible for on site measurements. This edition includes the following significant technical changes with respect to the previous edition:
- additional useful definitions introduced;
- definition of distribution type transformers introduced for the purpose this standard;
- new clause for sound level measurement specification introduced;
- requirement for 1/3 octave band measurements introduced for transformers other than distribution type transformers;
- standard measurement distance changed from 0,3 m to 1 m for transformers other than distribution type transformers;
- height of measurement surface is now clearly defined to count from the reflecting plane;
- measurement surface formula unified;
- correction criteria for intensity method introduced;
- rules for sound measurements on dry-type reactors introduced;
- figures revised;
- new informative test report templates introduced (Annex B);
- IEC 60076-10-1 (application guide) revised in parallel providing worthwhile information for the use of this standard.