Orono_Route_Permit_Application - Docket # W002/TL-11-223

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