Tests of acoustic field in closed areas of power plants

Marek Pierchała

Power objects belong to strategic installations. Characteristics of tested objects make tests and acoustic analyses more difficult. Thus, it was necessary to verify and compare available methodologies in difficult testing conditions of power objects. Methodologies based on PN-IEC 1063:1996 Standard and PN-EN ISO 3744:1999 Standard, as well as on the measurement of normal component of sound intensity were analyzed. Acoustic measurements and numerical tests of acoustic field distribution in closed areas are the subject of this monograph. The tests were carried out for a typical power plant.

They included three series of acoustic measurements: the first series was for power unit load equal to 100% PN, the second series was for power unit load equal to 60% PN, and the third series included the measurement of acoustic background. Moreover, three acoustic models were developed to assess the methodologies: model acc. to PN-IEC 1063:1996 Standard, model acc. to PN-EN ISO 3744:1999 Standard and author’s model. Each acoustic model was made for nominal load and minimal load (60% PN). Moreover, a series of continuous measurements, including measurements during warranty start-up of power unit, was made. Verifying tests confirmed that methodology based on the measurement of normal component of sound intensity should be used for analysis of power plants of complex spatial structure. This methodology enables obtaining in numerical tests the acoustic field distribution closer to real distribution than it is in the case of typical testing methodologies. Verifying tests carried out for the second series confirm conclusions from the first series of tests. It was also found that change in load of power unit is associated with significant change in sound emission. The character of these changes depends on design of each machine and equipment, and for part of these machines and equipment increase of sound emission is observed with decrease of load.