The invention relates to a device for eliminating 
voltage harmonics of a power 
system, which comprises a 
harmonic voltage source detection device, a fundamental wave filter, a 
high frequency transformer, an AC (
Alternating Current) power source, a 
power unit, a rectifying unit, a filtering unit and a controller, wherein the fundamental wave filter is formed by connecting a reactor 1, a reactor 2 and a 
capacitor in series; the 
harmonic voltage source detection device collects the real-time 
harmonic voltage of the 
system and inputs a harmonic voltage 
signal to the controller; the controller calculates out a voltage which is equal to the harmonic voltage in magnitude and opposite to the harmonic voltage in direction; the 
power unit inputs the voltage into an LC (Loop Circuit) 
branch, formed by connecting the reactors and the 
capacitor in series, through the 
high frequency transformer, and the voltage and the harmonic voltage are superposed so that the output harmonic voltage becomes zeroand the effect of filtering out the harmonic voltage in a 
power grid is achieved; and the controller is connected with the 
AC power source, the rectifying unit and the 
power unit respectively. In thedevice, based on the 
superposition principle, the purpose of eliminating the influence of a power-side higher harmonic 
voltage source to a load can be achieved by connecting the harmonic voltage sources in series, and the response speed is high.