Agenda - 05-27-2014 - C1 - Laserfiche WebLink

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Noise 33 Question. Do the inverters, transformers or other equipment used as part of ground- mounted solar PV create noise that will impact the surrounding neighborhood? Bottom Line. Ground - mounted solar PV array inverters and transformers make a humming noise during daytime, when the array generates electricity At 50 to 150 feet from the boundary of the arrays, any sound from the inverters is inaudible Parties that are planning and designing ground- mounted solar PV can explore options to minimize noise impacts to surrounding areas even more These could include conducting pre - construction sound studies, evaluating where to place transformers, and undertaking appropriate noise mitigation measures More Information. Most typically, the source of noise associated with ground- mounted solar PV comes from inverters and transformers There also may be some minimal noise from switching gear associated with power substations. The crackling or hissing sound caused by high - voltage transmission lines (the "Corona effect ") is not a concern in the case of solar PV, which uses lower voltage lines Parties siting ground- mounted solar PV projects should consult equipment manufacturers to obtain information about sound that can be expected from electrical equipment, which can vary For example, according to manufacturer's information, a SatConPowergate Plus 1 MW Commercial Solar PV Inverter has an unshielded noise rating of 65 decibels (dBA) at five feet This is approximately the sound equivalent of having a normal conversation with someone three feet away Another source of information is the National Electrical Manufacturers Association (NEMA) standards, which will provide maximum sound levels from various equipment arrays From NEMA, a large dry -type transformer (2001- 3333 kVA) that is forced air cooled and ventilated has an average sound level of 71 dBA, which is approximately the sound level one would expect from a vacuum cleaner at ten feet There may be several such units on a substantially sized PV site, which would increase the sound level to some degree Sound impacts from electrical equipment can be modeled to the property line or nearest sensitive receptor (residence) Sound impacts can be mitigated with the use of enclosures, shielding and placement of the sound - generating equipment on -site The rule of thumb for siting noise - generating equipment is that the sound impact can be reduced by half by doubling the distance to the receptor In some areas both in the U S and Canada, sound impact analysis is required as part of the permitting process for large PV systems For example, in the Province of Ontario, Canada, any project greater than 12 MW is required to perform a sound impact analysis (Ontario 359/09). California also requires a sound impact analysis for Large PV projects Massachusetts currently has no such requirement, but the reader should note that ground mounted systems in Massachusetts very rarely go over 6 MW, which is half the size of the 12 MW that triggers a sound analysis in Ontario A recent study measured noise levels at set distances from the inverters and from the outer boundary of three ground mounted PV arrays in Massachusetts with a capacity range of 1 to 3 5 MW Close to the inverters (10 feet), sound levels varied from an average of 55 dBA to 65 dBA Sound levels along the fenced boundary of the PV arrays were generally at background levels, though a faint inverter hum could be heard at some locations Any sound from the PV array and equipment was inaudible and sound 18