Request for Amended Advice Agency Response_Energex_Council CDA_01-04-2020

        J&P Richardson Industries Pty Ltd        -14-


6.0     DISCUSSION


6.1     Summary of magnetic field calculations

        The key results of sections 4.3 of this report with respect to magnetic field are summarised
        in Table 9 below.

        Table 9         Magnetic field levels for proposed 132kV constructions

                               CALCULATED MAGNETIC FIELD STRENGTHS (mG)
             Scenario
                                 Easement            Easement
                                                                         maximum
                                  (North)             (South)
                  1                0.54                 0.71               1.83
                  2                 0.71                0.83               2.26

        Scenario1 represents the system normal configuration with inbuilt escalation in the average
        132kV line currents to account to load growth. It therefore represents a ‘future’ average
        magnetic field level. Scenario 2 represents a ‘worst case’ field with both feeders in service.


6.2     Assessment of magnetic field levels

        It can be seen with reference to Table 9 and Table 3 that the calculated magnetic field
        levels are several orders of magnitude less-than the maximum permissible exposure levels.

        It is further noted that the calculated worst case magnetic field at the edge of the easement
        is less than 25% of the widely adopted industry reference value of 4mG adjacent the
        proposed lots. In addition the maximum magnetic field across the easement itself (under
        the powerline) is significantly less than this reference value.


6.3     Application of prudent avoidance principles

        Routine consideration must be given to measures that may reduce the magnetic field levels
        at the site within the scope of prudent avoidance. Even very minor cost impacts may be
        difficult to justify at this particular site given the very low prospective magnetic field levels.

6.3.1   ENERGEX transmission infrastructure.
        The conductor phase orientation on the two double circuit tower lines is already configured
        for minimum magnetic field level.

        The only other way that magnetic field levels associated with the transmission circuits could
        be reduced is by altering the physical construction of the support structures – by using
        more compact or taller structures, or undergrounding.

        Any of these changes would have either functional or significant cost impact and therefore
        not be within the scope of prudent avoidance.




        Hollett Road EMF Study                                                            V1.0