Environmental noise pollution control of substation by passive vibration and acoustic reduction strategies

Recently, residents in a specific urban area in China has complained against the noise pollution from a particular indoor substation. This paper aims at solving this problem through experimental investigations on the vibration and noise created by distribution transformers in the substation. Firstly, the noise around the distribution transformers, substation, and in the noise-sensitive room were measured. Secondly, through frequency characteristic analysis, the center frequencies at 250 Hz and 500 Hz with maximum values can be obtained and defined as main frequencies in this paper. Once the frequency of the main noises generated by the distribution transformers are identified, the sound absorbing structure, acoustic insulation structure, and vibration isolators were designed and installed. Following the treatment of noise pollution, the transformer and environment noise were reevaluated. The measurement results show that the integrated strategies proposed lead to effectively inhibiting the distribution transformer noise emitted into the surrounding environment. Consequently, the acoustic environment around the indoor substation was drastically improved. For this case study, the residential bedroom located above the substation is considered as a noise-sensitive room. The measurement following the treatment of noise shows that the average equivalent sound pressure level (SPL) in this room was successfully reduced approximately 6 dB at daytime and 10 dB at night, respectively. The corresponding measurement results illustrate that the SPL satisfied the requirement of limits of the ordinance. (C) 2020 Elsevier Ltd. All rights reserved.