|
|
PrattTribune - Pratt, KS
  • City going off the grid for upgrade

  • It won’t be an April Fool’s joke when the city of Pratt goes off-line on April 1 to replace a tap changer in the city electrical system. The change over is expected to last two weeks.


    • email print
  • It won’t be an April Fool’s joke when the city of Pratt goes off-line on April 1 to replace a tap changer in the city electrical system. The change over is expected to last two weeks.
    The city expects to save hundreds of thousands of dollars in maintenance costs over the next decade once the new tap changer is in place.
    “The new tap changer should eliminate the need for maintenance for 10 years,” said Kelly Hemphill, Pratt electric utility director.
    The city electricity supplier is Sunflower Electric. The tap changer is a large voltage regulator that helps maintain a stable voltage flow during fluctuations on Sunflower Electric power transmission lines from wind, trees, squirrels and other elements that cause the volts to go up and down, Hemphill said.
    The city has difficulties with squirrels getting into power lines and causing surges or outages. They have to put up squirrel guards to help keep them out of the system.
    It costs the city from $50,000 to $90,000 for maintenance on the tap changer. The current tap changer has a lot of years of use and requires maintenance every 1.5 to two years.
    The new tap changer plus labor will cost $200,000 but it should not need maintenance for 10 years so the city will save a substantial amount of money over the next decade.
    “We should have about a five-year payout,” Hemphill said.
    The new unit will be state of the art, top of the line tap changer and be more efficient than the current unit.
    The tap changer is inside the transformer that receives the direct feed from Southern Pioneer. City electric crews have to actually get inside the transformer to replace the tap changer. The incoming Southern Pioneer voltage is 115,000 volts and that is too high for the work that needs to be done. 
    “We can’t work on it with high voltage running through it,” Hemphill said.
    Since the necessary work on the tap changer cannot be done with that much voltage coming through the system, the city is going to have to go off-line and produce their own electricity during the change over process, he said.
    The city will use a 14-megawatt steam generator that produces 12,470 volts and was installed in 1964 but in excellent condition.
    The steam generator is favored over the dual fuel generators because the steam generator is much more stable if the system goes through any kind of interruption such as a vehicle hitting a power pole or a line coming down from a wind storm, Hemphill said.
    The steam generator can handle surges better than the dual fuel generators. Surges tend to cause the dual fuels to shut down and leave the city without power until they can be restarted.
    Page 2 of 2 - Running the steam unit will also take care of an annual need to run the steam generator to keep it current for transmission requirements.
    The city decided to wait until the first of April to do the upgrade because it will be past the cold winter weather and before the spring storms.

        calendar