[BC] Transmitter Safety

[Ron Nott]

Consider this.  While employed as Senior Electrical Test Engineer at 
the Four Corners Power Plant operated by Arizona Public Service Co., 
we had to hipot the generators (10 total) once a year.  The company 
provided me a journeyman electrician and an apprentice for this 
procedure.  First, I made sure that the breakers were open between 
the switchyard and the generator. Then we placed "mousing wire" 
between ground and everything that could contain an electric 
charge.  Then we lifted the grounded end of the wire and connected 
the hipot generator which provided 54 kV DC to the windings.  I had 
to turn it up slowly to charge the winding (one phase at a 
time).  Then we disconnected them (one at a time) and timed how long 
each took to discharge.  This is called the "polarization index".  It 
determines how much leakage there is between generator stator winding 
and ground.  Finally, we grounded everything completely.

It is interesting that we were required to do this on the night shift 
when there were a minimum of personnel on the turbine deck.  Minimum 
personnel equals minimum dead guys.

Units 4 and 5 have output voltages of approximately 22,000 volts per 
phase with approximately 20,000 amps per phase at full 
load.  Multiply the product of these two by the square root of 3 and 
you get about 760 megawatts.  Power factor on these units is 
0.9.  The transformers of unit 4 step the voltage up to 345 kV which 
goes to Phoenix, Albuquerque and elsewhere.  The transformers of unit 
5 step the voltage up to 500 kV which feeds the Moenkopi line which 
goes directly from the plant to the switchyard at Lake Mead (remember 
the lights in Las Vegas?).  Yes, 500,000 volts.  Really.

Top this for hazardous voltage working conditions.

Ron Nott