Harmonics are periodic distortions of voltage, latest, or power sine waves. Harmonics in ability distribution units are frequently attributable to non-linear loads for instance switched method dc power materials and adjustable velocity motor drives. trong m?t kho?n th?i gian nh?t ??nh tr??c khi ?i?u ch?nh, t?t nh?t b?n nên dùng ph??ng pháp t? ?