早在19世纪末，当交流电以一种新兴的动力形式出现时，人们就发现了系统中电压、电流存在畸变的问题。

As early as the end of 19th century, people had discovered the distortion problem of voltage and current existing in the distribution system when the alternating current arisen as a newly motive form.

youdao

早在19世纪末，当交流电以一种新兴的动力形式出现时，人们就发现了系统中电压、电流存在畸变的问题。

As early as the end of 19th century, people had discovered the distortion problem of voltage and current existing in the distribution system when the alternating current arisen as a newly motive form.

youdao