Description
Worldwide there is an increasing concern about the effects of power harmonics on electrical systems.Using their knowledge of hand held test equipmentand digital signal processing techniques Flukedeveloped these affordable, practical tools todiagnose power harmonics problems.
What are power harmonics?
Power harmonics are caused by non-linear loads suchas inverters (drives) and switch mode power supplies,even electronic ballasts for fluorescent lighting.Linear loads draw current in sine-waves at the supplyfrequency, non-linear loads do not, theseelectronically controlled loads tend to draw current inshort pulses causing a distorted current waveform tobe drawn from the supply.
AC theory demonstrates that non-linear currentconsumption actually consists of a sum of current at thesupply frequency and at multiples of the supplyfrequency. These multiples are the harmonics. Forexample if the supply frequency is 50Hz then thesecond harmonic is 100Hz and the third harmonic is150Hz, and so on. Because the electrical distributionsystem has a source impedance greater than 0W, largeharmonic currents will cause harmonics to appear onthe supply voltage. When this rises to significant levelsit may cause additional problems.
Why are power harmonics a problem?
Symptoms of harmonics usually show up in the powerdistribution equipment that support the non-linearloads. There are two basic types of non-linear loads -single-phase and three-phase. Single-phase nonlinearloads are prevalent in offices, while three-phaseloads are widespread in industrial plants.
Each component of the power distribution systemmanifests the effects of harmonics a little differently.Yet all are subject to damage and inefficientperformance.
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