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...
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...
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. ...
When a PV plant reaches MW scale, inverter control stops being the same thing as grid code compliance. Compliance is judged at the point of common coupling (PCC), where the utility measures voltage and current quality — not at the inverter terminals. A plant with well-behaved inverters can still fail its connection test for that reason, and a medium-voltage STATCOM is usually the device that...
Most AHF and SVG quotations are built backwards. A buyer collects a short-circuit level, a transformer rating and a target THDi, then asks three suppliers for a price. The result is a device sized to a guess rather than to the disturbance. A power quality report already contains most of what is needed to size a harmonic filter or reactive compensator correctly, provided the reader knows which colu...
Neutral conductor overheating in a three-phase four-wire system is a zero-sequence problem, so measure harmonic orders first and only then select a filter. A neutral that runs hot while the phases stay comfortably cool is rarely a coincidence. It points to zero-sequence current driven by triplen harmonics, which behaves nothing like a balanced-load calculation predicts. This article follows the or...
Industrial efficiency losses are not always mechanical. A plant can keep every machine healthy and still lose energy, capacity and uptime to harmonics, reactive power and three-phase current imbalance that never appear on a maintenance checklist. VFDs, rectifier-fed equipment and fast-switching electronics make production more efficient while making the network underneath less forgiving. This arti...
English
français
Deutsch
español
العربية
中文
IPv6 network supported
