Research on harmonic penetration between different voltage levels

Overall understanding on the nature and characteristics of the harmonics penetration between different voltage levels is necessary and significative. Factors affecting harmonic penetration are checked in the paper. After comprehensive analysis considering more than one factor simultaneously with the help of 3-dimension mesh plots, the distribution characteristics of with respect to key factors in acceptable ranges are summarized. Especially two kinds of situations in which the harmonic penetration coefficient is close to or even much larger than 1.0 must be regarded, one of which is owing to smaller impedance ratio, and the other is owing to the impedance angle of loads at next voltage level. The method proposed and results provided are universal to be applied.