Harmonics are periodic distortions of voltage, present, or electrical power sine waves. Harmonics in electric power distribution devices are frequently due to non-linear masses for example switched method dc electrical power provides and adjustable speed motor drives.Th?ng kê chu k? dàn loto T?n su?t dàn ??c bi?t B?ng ??c bi?t tu?n B?ng gi?i nh?