[BC] Tower Location Change For WLAN 1390

[RichardBJohnson at comcast.net]

No! Corona losses can't be "fixed" if the conductor is in air. At sea level, on a "standard day," corona occurs in air if the voltage gradient exceeds about 70 V/mil, i.e., 30 kV/cm. That is the ionization potential for air. That is why if you want to generate a quarter million volts corona free, for instance, you do it either in a vacuum, in oil, or under pressure in sulfur hexafloride.

Voltage gradients increase at sharp conductor corners, at the interface between dielectrics (insulators and air), and other places where electrostatic forces exist. Electrical distribution has tended towards increasing the voltages, thus reducing the current for a given power transmission. The limiting factor for the voltage increase, in the absence of enforcing regulations, has been corona. When an increase in voltage would increase the corona losses more than the resistive losses would be reduced, that voltage level is considered "optimum!"

If the FCC would enforce Part 15 regulations, local power distribution would have used about 5 kV, no more, unless all the equipment and methods were changed. For instance, you need insulators where, nowhere on the surface, would the voltage gradient exceed 30 kV /cm. You also need to remove all sharp ends of conductors, etc. Terminating a HV wire in a terminal would require spherical terminals in which the wire fits inside, resulting in no voltage gradients exceeding 30 kV. Certainly electrical distribution engineers know all about these things. However, they are required to maximize the return on investment so, when the FCC doesn't enforce rules, they can reduce the amount of money spent on the distribution system.

Cheers,
Richard B. Johnson
Book: http://www.AbominableFirebug.com/

----- Original Message -----
From: "Jerry Mathis" <thebeaver32 at gmail.com>

If true, this is very stupid. Why would they consider that "optimal"? I^R losses are unavoidable. But corona losses CAN be fixed.