Recently had a 480Y/277-volt, three-phase, four-wire feeder metered for one week. The following were the maximum load readings at each of the phases metered at 277-volts each.
Phase A (metered voltage 277-volts): 356A, 99.5 kVA Apparent Power
Phase B (metered voltage 277-volts): 309.5A, 85.7 kVA Apparent Power
Phase C (metered voltage 277-volts): 331A, 92.3 kVA Apparent Power
Power factor was right around 0.85 for each phase.
What is the correct way to calculate the overall load on the 480Y/277-volt system?
If I add together the three values for apparent power, I come up with a total of approximately 277.5 kVA for the 480-volt, 3-phase, 4-wire feeder which gives me approximately 333.8 Amps. I get this by the following:
227.5 kVA / 480-volts/ (sqrt of 3)
Is this correct?
Phase A (metered voltage 277-volts): 356A, 99.5 kVA Apparent Power
Phase B (metered voltage 277-volts): 309.5A, 85.7 kVA Apparent Power
Phase C (metered voltage 277-volts): 331A, 92.3 kVA Apparent Power
Power factor was right around 0.85 for each phase.
What is the correct way to calculate the overall load on the 480Y/277-volt system?
If I add together the three values for apparent power, I come up with a total of approximately 277.5 kVA for the 480-volt, 3-phase, 4-wire feeder which gives me approximately 333.8 Amps. I get this by the following:
227.5 kVA / 480-volts/ (sqrt of 3)
Is this correct?