Power conditioners (PC) FAQ

Eaton offers a comprehensive range of power conditioning (PC) products designed to address a wide variety of common power quality issues, including voltage regulation, sag protection, harmonic isolation and attenuation. Before determining the optimal device for your facility, it is helpful to gain a general understanding of the specific power quality issue you are facing, as well the key factors to consider when selecting a power conditioner for your application.

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What is a power conditioner?

A power conditioner is a general term to describe a piece of equipment that can be used to improve a system’s power quality. While at times used to refer specifically to an uninterruptible power supply (UPS), that is only one of many products that fits the term. Other products include voltage regulators, noise attenuating transformers and active harmonic filters.

What is power quality?

The Institute of Electrical and Electronics Engineers (IEEE) defines power quality as “powering and grounding electronic equipment in a manner that is suitable to the operation of that equipment and compatible with the premise wiring system and other connected equipment.” For owners and operators of electronic equipment, this definition can be expanded to include factors that impact the overall lifespan of equipment; for example, the damaging and life-reducing effects of harmonics.

Is there one power conditioner that will solve all power quality problems?

An effective power conditioning solution can vary dramatically among different organizations and facilities. Specific power quality issues present within the electrical system, business goals and load profiles are among the considerations when assessing or configuring a solution. The “black box” approach is seldom an electrically suitable or cost-effective solution. Engaging in a power factor study or mini–power factor study can go a long way toward identifying problems and implementing an optimal solution. 

What are voltage variations?

There are two components of voltage variation ── magnitude (how far voltage has deviated from nominal) and duration (the amount of time over which the deviation occurs). Either of these factors can result in a variety of dangerous power quality conditions, including overvoltage, surges and sags. Overvoltage occurs when the voltage exceeds nominal for a sustained period of time, either for multiple cycles or lasting indefinitely. A sub-cycle overvoltage event is referred to as a surge, which is categorized as a brief overvoltage or disturbance on a power waveform that can damage, degrade or destroy electronic equipment. A sag, on the other hand, is a sustained condition of decreased voltage below nominal for multiple cycles. A sag that drops to zero for any amount of time is referred to as an outage.

Should the measured voltage rating always be equal to the nominal voltage

Incoming voltage to facilities can vary, as can the voltage to an individual piece of equipment. The typical magnitude of a good voltage source is +/-5% of the nominal voltage (208, 240, 480, etc.). While electric utility companies must meet specific requirements for nominal voltage, those conditions often fall outside of a +/-5% tolerance. Furthermore, the operating tolerance of many devices is often even tighter.

What are harmonics?

Harmonics ── defined as the content of the signal whose frequency is an integer multiple of the system's fundamental frequency ── causes a distortion in the waveform shape of the voltage and current, increases current level and changes power factor supply. This, in turn, can result in a variety of damaging power quality issues. Nuisance operation of fuses and breakers, insulation deterioration and audible noise in electrical equipment can all be early indicators that harmonics is present.

Click here to learn about Eaton's Active Harmonic Correction Unit (HCU2). 

What are the effects of harmonics?

Harmonics can lead to equipment malfunction and failure. Notching ─ a voltage waveform distortion resulting from short-duration high current pulses ─ causes control malfunction and regulator mis-operation, while increased current can lead to overheating and failure of transformers, motors and cables. There are also economic considerations where harmonics are concerned. Some organizations will intentionally oversize equipment in an attempt to accommodate harmonics, losses and inefficiencies. Others may not be able to install capacitors they need avoid power factor correct (PFC) penalties, and may require more expensive detuned filters or active VAR injectors

What is IEEE-519?

A system guideline for setting limits on voltage and current distortion, the intent of IEEE-519 is to ensure that utility companies provide a “clean” voltage and limit harmonic current from customers, who must protect their infrastructure and limit disruptive impact on critical loads. This is important because harmonics affect multiple entities. For instance, harmonic polluters feed the distortion from their facility bank onto the electrical grid, with other nearby customers able to see the effects of that distortion within their own facilities. Equipment manufactures specify the levels of harmonic distortion at which their equipment is suitable to operate (typically an upper limit), but if a facility’s distortion levels are too high, that equipment may not operate properly or could be damaged. Manufacturing equipment to operate at higher distortion levels ─ if even possible ─ would entail a significant expense. 

When it comes to harmonics, which comes first ── voltage distortion or current distortion?

Current distortion causes voltage distortion, which is created by pulling distorted current through an impedance. The amount of voltage distortion depends on system impedance and the amount of distorted current pulled through the impedance. If either increase, voltage total harmonic distortion (VTHD) will increase.

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