Thursday, July 19, 2007

What Is Power Quality and Why Do I Need a Power Quality Analyzer?

The dependability and cost of any electrical system depends greatly on the quality of the powerfulness supplied to and consumed by the system. Poor powerfulness quality may ensue in improper function, overheating, accelerated wear and tear, falsely tripped electrical circuit surf and, in some cases, risky conditions. With the introduction of new electronic engineerings over the last respective decades, the human race have placed new and more than composite demands for clean and dependable power.

Measuring Power Quality typically affects calculating indexes of powerfulness demand, powerfulness ingestion and powerfulness cleanliness. By measurement demand and consumption, consumers can place cost centres in their electrical substructures as well as applied scientist the electrical substructure required to ran into those demands. By measurement cleanliness, consumers are able to avoid improper function, overheating and a nimiety of other effects of dirty power.

What is powerfulness demand and how make we measurement it?

Power demand is the amount of norm electrical energy that is consumed over some clip period of time by a device, machine building, etc... Power Quality Analyzers, electronic instruments used to mensurate indexes of powerfulness quality, can average out the electrical energy and show it in units of measurement of "kilowatts". It is of import that electrical systems are supplied with adequate powerfulness to ran into extremum clip periods of demand.

How makes powerfulness ingestion differ from powerfulness demand?

Power consumption, similar to demand, is the "sum" of electrical use over time. Power demand reflects an instantaneous position of electrical usage, whereas, powerfulness ingestion sums of money the electrical use over the same clip period of time. Power Quality Analyzers measurement ingestion in units of measurement of watthours (Wh) or kilowatthours (kWh). Most computations of the cost of powerfulness are based on ingestion and measured by $ per kWh.

Once we cognize powerfulness consumption, we can cipher a utile metrical called "Power Factor". Power Factor is a ratio of the existent powerfulness used by an electrical system to the evident powerfulness delivered by the utility. In almost all cases, the existent powerfulness used will be less than the evident powerfulness delivered because of heat energy dissipation, frictional loss, work performed and other release of energy by the electrical system.

We can utilize Power Factor to assist us set a terms tag on the amount of work the electrical system is performing, as well as aid us put in capacitances and other devices that shop existent energy to avoid being charged for extra evident power. With a Power Quality Analyzer, you can cipher the "Reactive Compensation", the amount of capacitive value required to rectify a low Power Factor.

Power cleanliness and the demand to understand harmonics

Power cleanliness mentions to the identifying and liberation powerfulness of "harmonics". The conception of harmonics is a spot more hard to understand than demand and consumption. Harmonics are a consequence of non-linear loads that cause irregular spikes and dips in electromotive force and current on an electrical system.

The powerfulness provided by public utility companies is delivered in the word form of a changeless electromotive force actinium (Alternating Current) and takes the form of a sine wave. Ohms law states the amount of current used by an electrical device depends on the loading (inductance) of that device. If the loading changes over time, so will the current. Harmonics look when varying tons (non-linear) make short pulsations of current that deform the supplied, sinusoidal current waveform, creating an arbitrary waveform.

You can believe of an arbitrary moving ridge as being made up of respective cardinal waveforms. The easiest illustration of an arbitrary moving ridge is to image two people on opposite sides of a pool who each make a moving ridge towards each other with a pool float. When the moving ridges intersect in the middle, the consequence is a moving ridge that is twice as tall. The consequent moving ridge is made up of two cardinal waves.

This illustration can be used to explicate that haps when harmonics happen owed to non-linear loads. The current moving ridge goes deformed from a perfect sine moving ridge and extrema and vales make un-clean power. Harmonics can do devices to overheat, electrical wire evaluations to be reduced, motors to prematurely have got on and electrical circuit surf to falsely trip.

Power Quality Analyzers have the ability to place and analyse the cardinal harmonics that do up an arbitrary current wave. Measurements such as as Doctor of Theology (Total Harmonic Distortion) can state you the part of harmonic electric currents to the cardinal current required. Measured as a percentage, 10% would be a ground for concern. Another measuring called "Crest Factor" will bespeak the degree of peaking caused by harmonics. The Crest Factor is a ratio of the Extremum Value / RMS Value, which in a perfect sine moving ridge would be 1.414.

Choosing a Power Quality Analyzer

There are a figure of different Power Quality Analyzer makers such as as Fluke, AEMC, Hioki and Extech. Some analysers are designed to mensurate single form systems while others are for three form systems. Many PQAs incorporate with PCs, have got enhanced information logging capablenesses and can bring forth professional studies typically requested for powerfulness quality applications. Power Quality Analyzers scope in terms from $1500 to $6500 with the more than expensive merchandises offering greater analysis functionality.

Whatever your application or budget, it is of import that powerfulness quality is a factor in the designing and care of your electrical system. Power quality is a military unit to be reckoned with whether you are trying to cut down costs, avoid downtime, and addition the service life of your system.

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