Agenda - Council - 06/25/2013 - Laserfiche WebLink

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Enterprise Park to Crooked Lake 115 kV Transmission Line March 2012 Environmental Assessment EMFs may cause EMI with implantable medical devices. This interference disrupts the cardiac device's ability to sense normal electrical activity in the heart. Although most modern cardiac devices are less susceptible to effects from EMFs due to engineering design, older designs can still be affected. In the event that a cardiac device is impacted, the effect is typically a temporary asynchronous pacing (i.e., fixed rate pacing) and the device would return to its normal operation when the person moves away from the source of EMFs (PSCW, 2010). The Project's maximum calculated electric field at 1 meter above the ground would be 1.83 kV/m and would occur directly under the centerline of the transmission line. For all distances from the centerline, the calculated electric fields would be below the common manufacturer guideline of 6 kV/m for avoiding EMI. Stray and Induced Voltage Stray voltage is an extraneous voltage that appears on grounded surfaces in buildings, barns, and other structures. Stray voltage and its impact is normally an issue associated with electric distribution lines and is a condition that can exist between the neutral wire of a service entrance and grounded objects in buildings. The source of stray voltage is a voltage that is developed on the grounded neutral wiring network of a building and/or the electric power distribution system. Stray voltage can result from damaged, corroded, or poorly connected wiring or damages insulation. Transmission lines do not, by themselves, create stray voltage because they do not connect to businesses or residences. The Project would have no direct electrical connection to conductors originating in another system; it would not connect with the local distribution system. Transmission lines, however, can induce stray voltage on a distribution circuit that is parallel and immediately under the transmission line. Induced voltage between a transmission line and distribution circuit only occurs in the immediate vicinity of the distribution circuit and does not travel along the transmission or distribution line. Stray voltage safety concerns are primarily associated with distribution lines. Stray voltage is not identified as a safety concern associated with the Project; however, since transmission lines can induce stray voltage on distribution circuits that are parallel and immediately under a transmission line, mitigation measures may be necessary if the Project transmission line parallels or crosses distribution lines. Induced voltage between a transmission line and distribution circuit only occurs in the immediate vicinity of the distribution circuit and does not travel along the transmission or distribution line. Each of the Project Route Alternatives would require crossing and paralleling distribution lines. Stray voltage is often not noticeable to humans, but may be felt by an animal (PSCW, 2010). The Applicant would address stray voltage issues on a case by case basis. The three primary methods to reduce or eliminate stray voltage are cancellation, separation, and enhanced grounding. Cancellation entails the arranging of transmission line phase conductors in a configuration to minimize EMF levels, bonding distribution neutral and transmission shield wires together, and bonding an under -built transmission shield wire to distribution neutral wires rather than a normal overhead shield wire. Separation entails 40