Harmonic Distortion

Harmonic Distortion is any distorted voltage and current waveform that deviates from an ideal sinusoidal waveform. Harmonic distortion presents potential harm and equipment downtime to electrical components. Non-linearloads connected to the electrical supply in facilities cause harmonics (waveform distortions) on the power distribution system. Common non-linear loads include solid state motor soft starters, variable frequencydrives, computers, electronic lighting, welding supplies and uninterrupted power supplies.

The Institute of Electrical and Electronics Engineers (IEEE) has established a recommended practice – IEEE 519-2014- which sets limits for harmonic current and voltage distortion for electrical power systems.This recommended practice provides the foundation for evaluating the level of harmonic distortion in a power distribution system, and the level of action required to mitigate the risks.Industries such as water and waste water treatment, and HVAC, must meet local requirements to achieve low harmonic levels; this prevents disturbances to equipment in nearby residential properties and commercial buildings.Harmonic distortion can impact a system in many ways: it can cause distribution transformers to overheat, resulting in insulation breakdown and failure; electronic displays and lighting may flicker; nuisance tripping of circuit breakers is possible; and damage can occur to electronic equipment. Harmonic distortion effects are not limited to the facilities where electrical equipment is installed. This potentially impacts any residential and commercial areas, where electrical equipment is installed such as: pumping stations, waste water treatment plants, cooling towers and HVAC systems.

Harmonic Distortion Reduction

Professionals responsible for designing and maintaining electrical systems must be aware of the potential issues related to harmonic distortion of their power distribution systems; and know how to manage them in the most efficient and cost effective manner.Many factors and components impact the overall quality of a power distribution system. Variable frequency drives (VFD’s) are among the many electrical devices included in that group. Manufacturers of variablefrequency drives offer a variety of answers to the question of how to reduce the levelof distortion these devices produce. Most of these solutions involve adding large, costly components like specialty transformers to the variable frequency drive installation to reduce the level of harmonic distortion.

ABB offers a broad range of Ultra Low Harmonic drive solutions. ABB ULH drives have built-in components to reduce harmonic distortion. ABB ULH drive solutions provide the best combination of harmonic reduction, package size, weight and range of features.The ABB Ultra-low Harmonic drive solution provides the best overall management of harmonic distortion of all solutions tested. Not only are the current and voltage distortions minimized, but the power factor is controlled to operate at unity (1.0), minimizing the total current used by the drive. ABBULH drives are the ideal solution for those drive installations where low harmonic content is desired or mandated. Its footprint is generally smaller than com parable stand-alone installations that use additional bolt-on harmonic reduction means. Its performance and simplicity of installation make it suitable for the water and wastewater industry, which includes applications such as: pumps, blowers, and compressors.

For more information about harmonic distortion or for variable frequency drive repair and replacement quotes, contact Precision Electric.