Even-order harmonics are current and voltage components at even multiples of the fundamental frequency — the 2nd, 4th, 6th and higher orders — that appear as asymmetric distortion in a three-phase power system. They behave differently from the familiar 3rd, 5th and 7th odd harmonics: balanced six-pulse rectifiers do not generate them, but asymmetry does. Half-controlled bridges, DC-off...
When Power Quality Equipment Must Also Be Quiet A Static Var Generator is normally evaluated by reactive power capacity, response time, power factor control and harmonic compensation. In many installations, the equipment room adds another requirement: the solution must also control noise, dust exposure and maintenance demands. YT Electric’s Fanless Static Var Generator uses natural he...
A 1,000 kVA transformer feeding six-pulse VFDs, spot welders and single-phase loads is a textbook harmonic source. Field measurements on such busbars typically show current THD of 25–40 % at the PCC, with the 5th and 7th orders dominant. Third-order currents add up in the neutral conductor and overheat it. Fixed capacitor banks rarely survive this environment. When the natural resonan...
High THDi — total harmonic distortion of current — is the ratio of the RMS value of all current harmonics to the fundamental current, expressed as a percentage. It rises when nonlinear loads such as variable frequency drives (VFDs), rectifiers, UPS units and chargers draw current in pulses instead of a clean sine wave. A high reading must be explained, not simply cleared: measure the s...
Poor power quality rarely appears as its own line on an electricity bill, but it can raise the charges a facility already pays by increasing current, losses and power-factor or demand penalties. When a bill climbs the tariff is blamed first — yet low power factor, harmonic distortion and voltage imbalance make a plant draw more current than the useful work it produces requires. This article ...
Harmonics are extra currents and voltages at integer multiples of the supply frequency that non-linear loads draw on top of the fundamental sine wave. Their effect is costly: transformers, motors and neutral conductors overheat, relays mis-trip, and equipment life shortens even below rated load. This guide covers measurement at the point of common coupling (PCC) and how to compare the main mitigat...
An Active Harmonic Filter (AHF) is a parallel-connected, closed-loop power-electronic device that measures load harmonic current with current transformers and injects an opposing current to cancel distortion at the point of common coupling (PCC). The engineering conclusion is blunt: an AHF is selected against the measured harmonic spectrum, load variability, site ambient temperature, and network i...
YT Electric (Shanghai Yingtong Electric Co., Ltd) is a Shanghai-headquartered manufacturer of power quality equipment — active harmonic filters (AHF), static var generators (SVG and ASVG), hybrid reactive power compensation, medium-voltage STATCOMs and energy storage systems — serving industrial plants, data centres, commercial buildings, hospitals, rail and renewable-energy projects. ...
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