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345 kV Transmission Line from Brookings County, South Dakota to Hampton, Minnesota, Docket No. ET- ' <br /> 2/TL-08-1474, Order Granting Route Permit (adopting ALJ Findings of Fact, Conclusions and <br /> Recommendation at Finding 194 (April 22, 2010 and amended April 30, 2010)) (September 14, <br /> 2010). The standard was designed to prevent serious hazards from shocks when touching large <br /> objects parked under AC transmission lines of 500 kV or greater. Other concerns that have been <br /> raised regarding electric fields include biological responses and health effects, stray voltage, noise, <br /> television and radio interference, further discussed herein. The maximum electric field,measured at <br /> one meter (3.28 feet) above ground, associated with the Project is calculated to be 0.437 kV/m (see <br /> Table 6 below). <br /> Table 6 <br /> Calculated Electric Fields (kV/m) for Proposed <br /> Transmission Line Design <br /> (3.28 feet above ground) <br /> Maximum Distance to Proposed Centerline(feet) <br /> Operating <br /> Structure Type Voltage(kV) -300 -200 -100 -75 -50 -25 0 25 50 75 100 200 300 <br /> Single Pole Davit <br /> Arm 115 kV Single 121 .007 .018 .089 .154 .267 .345 .390 .012 .005 <br /> Circuit <br /> Single Pole Braced <br /> Post 115 kV Single 121 .005 .012 .051 .087 .153 .243 .084 .050 .013 .006 <br /> Circuit <br /> Single Pole Davit <br /> Arm 115 kV/115kV 121 .002 .005 .011 .005 .071 .437 .341 .071 .005 .011 .005 .002 <br /> Double Circuit <br /> 5.2.2 Magnetic Fields <br /> There are presently no Minnesota regulations pertaining to MF exposure. Xcel Energy provides <br /> information to the public,interested customers and employees so they can make informed decisions <br /> about MFs. Such information includes the availability for measurements to be conducted for <br /> customers and employees upon request. <br /> The magnetic field profiles around the proposed transmission lines for each structure and conductor <br /> configuration being considered for the Project is shown in Table 7. Magnetic fields were calculated <br /> under normal system conditions (systems intact) for the expected peak and average current flows as <br /> projected for the year 2011-2021. The peak magnetic field values are calculated at a point directly <br /> under the transmission line and where the conductor is closest to the ground. The same method is <br /> used to calculate the magnetic field at the edge of the right-of-way. The magnetic field profile data <br /> show that magnetic field levels decrease rapidly as the distance from the centerline increases <br /> (proportional to the inverse square of the distance from source). <br /> The magnetic field produced by the transmission line is dependent on the current flowing on its <br /> conductors. Therefore,the actual magnetic field when the Project is placed in service is typically less <br /> than shown in the charts. This is because the charts represent the magnetic field with current flow <br /> at expected normal peak based on projected regional load growth through 2011-2021,the maximum <br /> load projection timeline available. Actual current flow on the line will vary, so magnetic fields will <br /> be less than peak levels during most hours of the year. ' <br /> Orono Project June 7,2011 <br /> MPUC Docket No. E002/TL-11-223 32 <br />