peter,Distortion on a current waveform is normal, there are a number of potential sources.
The B/H curve of the iron core is not linear and there can be localised areas of saturation which you can only discover by modelling the magnetic circuit. Kermit2 has pointed out the phase shift issue. The meter, which loads the circuit will have an electronics board with a bridge and a capacitor which also distort the current waveform. I think what you are seeing is normal and not much can be done.
What is your problem? are you testing meters and worried about accuracy?
Peter
I need to worry because if i will connect load at output of meter which expects pure sine wave, this distorted wave can damage that load.
My ultimate aim is to boost sinusoidal current waveform from 0.5A to 10A. 0.5A is maximum current i can pass in inverter board.
help.