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#129851 - 09/26/05 07:45 AM Standard of voltage unbalance level
vandax Offline
Junior Member

Registered: 07/29/05
Posts: 4
Loc: Sumatra, indonesia
We are operating 3 phases radial system with part of load is 2 phases transformer and some percent of load also use 3 phase load especially for motor /AC or other 3 phases load.

The fact that system loading cause the voltage to be unbalance about 2-3 % of the average voltage value. We know that it may increase the motor temperture excessively, due to presence of negative seq current.

Would please help me or direct me to find the reference what is the acceptable unbalance voltage provided by the utility for customer?

Thanks for your help

#129852 - 09/26/05 09:09 AM Re: Standard of voltage unbalance level
Dave T Offline

Registered: 01/22/05
Posts: 157
Loc: Waukesha, WI, USA
My curve shows a 5-10% derating.
This is my referrence:
As shown it is not recommended that more than 5% be allowed.

#129853 - 10/01/05 07:22 PM Re: Standard of voltage unbalance level
WFO Offline

Registered: 09/03/05
Posts: 206
Loc: Cat Spring, TX


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