ABSTRACT
Noises in the substations are caused by equipment such as transformers, reactors, filters and fan cooling devices (Wang,2008; Wu,2010). Low-frequency electromagnetic and mechanical noises produced by the transformers are the main sources of noise (Chen,2006). At present, two kinds of measures have been taken to reduce the noise exposure from the substations. One is to reduce the noises at their sources. This involves device modification within the substations and has disadvantages such as more time consumption, high cost and poor feasibility. Furthermore, not more than 15 dB noises can be reduced (Geng,2013). The other measure is to separate the living environment from the sound source. Sound waves are blocked and weakened on their propagation pathway using sound absorption materials and soundproof configurations, such as large sound barriers along the substation boundary and “box-in” packaging technique towards the main devices (Chen,2006; Zhou,2009; Chen,2008; Ou,2005). The latter has gained increasing attention due to its noticeable cost-effectiveness, smallscale construction and uninterrupted installation.
