Harmonics are periodic distortions of voltage, recent, or power sine waves. Harmonics in electric power distribution systems are frequently due to non-linear loads such as switched manner dc electrical power materials and adjustable speed motor drives.T?n su?t c?p Loto T?n su?t Lô r?i T?n su?t gi?i ??c bi?t Th?ng kê chu k? loto. Page 61 Industria