In electrical power systems, harmonics are typically categorized into three primary classifications based on their phase sequence behavior and rotational impact on three-phase rotating machinery: positive sequence harmonics, negative sequence harmonics, and zero sequence harmonics. Positive sequence harmonics—such as the 4th, 7th, and 10th orders—rotate in the same direction as the fundamental wave. Negative sequence harmonics—such as the 2nd, 5th, and 8th orders—rotate in the opposite direction, creating braking torques and motor overheating. Zero sequence harmonics—such as the 3rd, 9th, and 15th triplen orders—are in phase across all lines and concentrate heavily within the neutral conductor.