Current Unbalance Due To 1Phase Loading
Current Unbalance Due To 1Phase Loading
(OP)
In a 3 phase 3 wire system, the voltages are measured at 242VAC. The currents are measured at 20A, 18A and 7A. If these are single phase line-to-line loads, in the absence of a panel schedule, can we say that the power consumption will be 1.732 x (20A + 18A + 7A)x 242V ?
It is also observed that the current unbalance due to actual loading is severe 100%-[(7/20)x 100%] = 65% unbalance. Is there a way to avoid this much of unbalance regardless of load switching arrangement or is it a fact that if the panelboard circuits were properly balanced, then there is no way of any unacceptable current unbalance regardless of how much loads are switched on?
It is also observed that the current unbalance due to actual loading is severe 100%-[(7/20)x 100%] = 65% unbalance. Is there a way to avoid this much of unbalance regardless of load switching arrangement or is it a fact that if the panelboard circuits were properly balanced, then there is no way of any unacceptable current unbalance regardless of how much loads are switched on?






RE: Current Unbalance Due To 1Phase Loading
RE: Current Unbalance Due To 1Phase Loading
My question is if there is another way of making the computations adding up the total power per phase in this unbalanced condition?
RE: Current Unbalance Due To 1Phase Loading
RE: Current Unbalance Due To 1Phase Loading
RE: Current Unbalance Due To 1Phase Loading
Your sum of (20+18+7) = 45A = 3 TIMES the average phse current. The average phase current = 45/3=15A. If you use 45, then you need to divide by 1.732; if you use 1/3 x 45 = 15, then the 1.732 goes on top:
P=IV sqrt(3)
P=15x242x1.732 = 6.3kVA
P=45x242/1.732 = 6.3kVA
P=45x242x1.732/3 = 6.3kVA
P=(20A + 18A + 7A)x242/1.732 = 6.3kVA.
RE: Current Unbalance Due To 1Phase Loading
RE: Current Unbalance Due To 1Phase Loading