system loss reducing with a kvar energy controller

System Loss

system loss reductions with a kvar energy deviceIn recent years, a system loss of 2% to 3% would be accepted in trade for lower system component costs. Today, these initial component costs must be very carefully weighed against a higher long term system operating cost.

Depending on the local price of electricity, it is probably more worthwhile now to spend more initially on the system to get components that will have minimal operating losses.



The range of losses in power system equipment at full load is summarized below: 

  • Outdoor circuit breakers 0.002% - 0.015%
  • Medium voltage switchgear 0.005% - 0.02%
  • Transformers 0.4% -1.9%
  • Load break switches 0.003% - 0.025%
  • Bus way 0.05% - 0.50
  • Low voltage switchgear 0.13% - 0.34%
  • Motor control centers 0.01% - 0.40%
  • Cable 1% - 4%
  • Motors (can only be figured after sizing)
  • 1-10 HP 14% -35%
  • 10-200 HP 6%-12%
  • 200-1500 HP 4% - 7%
  • Static variable speed drives 6%-15
  • Capacitors 0.5%-2%
  • Lighting 3% - 9%

The component with the greatest percentage of loss that is a part of the power distribution system is the cable. Conductor current carrying capacity or 'ampacity' is determined by the maximum operating temperature that its insulation can with-stand.

The heat that produces the conductor temperature rise is caused by the wattage loss in the conductor. Both aluminum and copper conductors can be obtained. Aluminum has a higher electrical resistance than copper, so aluminum wire has a lower current rating than copper wire of the same size since its higher resistance generates more heat.

Thus, the maximum operating temperature of the conductor is reached with lower current. To carry the same amount of current, the aluminum conductor must be larger. The appropriate size of each conductor and its initial cost should be considered when selecting the type to be used.