Design and application of sound barrier for substation noise control

After measuring the noise of transformers, substation boundary and noise-sensitive area of a 110 kV substation, it’s known that the noise at substation boundary contains transformer noise component via analyzing the 1/3-octave band spectrums. The octave band sound pressure level on the roof of the east residential building derived from the transformer is obtained by sound field prediction of SoundPLAN. Moreover, the NR-40 curve is used to evaluate the octave band sound pressure level to calculate the theoretical noise reduction of the east residential building. Considering the direct propagation and another propagation path undergoing reflection, a sound barrier that composed of sound insulation board with a significant sound insulation effect is designed for the frequency band below 1000 Hz. After completely installing the sound barrier, the noise level at measuring point 16 at night is reduced from 55.9 dB(A) to 46.7 dB(A), with noise reduction of 9.2 dB(A); while it is reduced from 56.3 dB(A) to 44.5 dB(A) at measuring point 21, with noise reduction of 11.8 dB(A).