THD Engineering provides consultancy services about harmonic analyses and solutions for reliable and sustainable power systems in industrial facilities. Power quality products include active, passive and hybrid harmonic filter systems, detuned harmonic filter systems, solutions of the unbalance problems and A Class power quality analyzer devices. we provided measurement and design solutions for over 400 facilities and completed site applications for over 200 projects so far. THD Engineering guaranties the service quality for design and site application about harmonic problems.