A study on the control indices and emission limits of substation noise

Equivalent continuous A-weighted sound pressure level (LAeq) underestimates the influence of low-frequency components of substation noise, so it is necessary to optimise control indices and emission limits of substation noise. To this end, 148 noise samples from 110 kV-1000 kV substations were selected. 280 subjects were randomly recruited for listening tests in which the 11-point numerical scale specified by ISO 15666-2021 was used. The mean noise annoyance (Am) of each noise sample was obtained to establish the LAeq-Am model of substation noise. Meanwhile, the LAeq-LFNR model was estab-lished based on the low-frequency noise rating number (LFNR) proposed by Broner. Based on these mod -els, the LFNR corresponding to the limit of LAeq could be determined. The limit of sound pressure level of substation noise was proposed at each 1/1 octave band from 31.5 Hz to 500 Hz and the limit-exceeding ratio for the existing substations noise of China was analyzed. Results showed that Am of 500 kV-1000 kV substation noise was 1.0 higher than that of 110 kV-220 kV substation noise on average when LAeq was 25 dBA-80 dBA. LAeq of the latter were 6.1 dBA higher than that of the former on average when Am was 1- 10. It was estimated that utmost 20 % of substations need further to take noise control measures in order to meet the limit suggested by this study in China. Binding with the limit of LAeq, the limit of sound pres-sure level at each octave band proposed according to equal noise annoyance can better evaluate the influ-ence of substation noise.(c) 2023 Elsevier Ltd. All rights reserved.