Data Sheet

Total Harmonic Distortion (THD) /
Unbalance
This section contains summaries of THD for voltage and current.
Additionally graphical summaries of voltage and current unbalanced are displayed during the
monitor interval.
There are international standards recommending the allowable level of harmonic distortion, the
levels vary depending on the operating voltage level, it is recommended that you consult the
local prevailing standard for comparison with the levels found in this report.
Excessive voltage unbalance is an indication that one or two phases may be overloaded. A
redistribution of the loads on one or more of the phases may be in order.
Excessive current unbalance also indicates a poor distribution of loads. Although there may be
no corresponding voltage unbalance, excessive current unbalance may result in tripped circuit
breakers or transformer overheating.
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1/6/2011