Unisin 3100 Broad Spectrum Harmonic Filter
Avoidance of Generator Derating
Application Note May 2003
It is well known that harmonics have significant adverse effects on generator performance. In addition to numerous publications on this subject, IEEE-519 has a section entitled “Effects of Harmonics”, which describes the impact of harmonics on generator systems.

The major effects of concern may be summarized as follows:

  1. Derating due to overheating
  2. Mechanical oscillation
  3. Additional pulsating or reduced torques
  4. Malfunction of generator-regulating control.

Harmonics will reduce the life and performance of generators. Normally a small amount of harmonics, less than about 4%, has negligible impact on the generator system but can still reduce electric performance by 5% or more. Higher levels of harmonics can result in far more severe reductions in power output. Elimination, or at least minimization of harmonics is therefore desirable.

Our unique Broad Spectrum Harmonic Filter, the Unisin 3100, consists of 2 major parts: a series component and a shunt component. The series component is a reactor that functions to prevent the flow of harmonics towards the generator and a shunt component, which is an all-around filter that filters out all harmonics. If the filter is designed to filter out 3rd or 5th harmonics, then the filtering efficiency at the design harmonic is typically over 95%; efficiencies for other higher order harmonics are typically about 65%.

Our design of the Unisin 3100 is based on user requirements so that one filter will handle all of the harmonics for a major savings in cost and space. Moreover, the Unisin 3100 contains no electronic parts and so is very reliable.

It is commonly recognized that a solidly grounded neutral of a generator in low voltage systems, say 3 phase 4-wire 480 volts, can have severe effects on the generator’s derating due to circulation of the 3rd harmonic through the ground loop. A derating also occurs when a generator is impedance grounded in medium voltage systems. The Unisin 3100 can filter out the 3rd harmonic without impacting the service of 3 phase 4-wire systems for single-phase loads.

The Unisin 3100 Broad Spectrum Harmonic Filter can meet your need to avoid derating.

Please feel free to contact us for free consultation.

© 2003 Unisin Power Technology
Unisin Power Technology, P.O. Box 3308, 444 North Amelia Avenue, San Dimas, CA 91773 USA
Tel: 909-305-4846, Fax: 909-971-0206, Email: eng@unisin.com
Customer Service: 866-521-4926
Web: www.unisin.com