Harmonics may alter your measurements as you measure an alterred wave with equipment built for sinusoidal waves. It may happen that during your measurement the distortion will increase or decrease the quantity measurev (V I) or it may disturb the impedence of the equipment used to measure . For measuring in an environment with harmonics you have to use adequate equipment , as minimum for example you have to use True rms measuring Clamp Amper-Meters or you need to know that your Voltmeter is able to measure a distorted wave. Any how if you know you have harmonics use only equipment that is designed to work with harmonics .
Any other question I will be pleased to help. A.Rash BScEE & PE
a_rash@bigfoot.com
Suggestions:
1. Select a meter that measures true RMS
2. Use oscilloscope or harmonic analyzer to obtain the extent of the harmonic content and harmonic distortion
3. It also depends what you intend to measure. The power measurements that involve contaminated voltage and current by harmonics in a multi-phase power supply system are more involved
