Harmonics appear when varying loads (non-linear) create short pulses of current that deform the supplied, sinusoidal current waveform, creating an arbitrary waveform. If the load varies over time, so will the current. Ohms law says the amount of current used by an electrical device depends on the load (inductance) of that device. The power provided by utility companies is delivered in the form of a constant voltage AC (Alternating Current) and takes the shape of a sine wave. Harmonics are a result of non-linear loads that cause irregular spikes and dips in voltage and current on an electrical system. The concept of harmonics is a bit more difficult to understand than demand and consumption. Power cleanliness refers to the identifying and freeing power of “harmonics”. Power cleanliness and the need to understand harmonics With a Power Quality Analyzer, you can calculate the “Reactive Compensation”, the amount of capacitive value required to correct a low Power Factor. We can use Power Factor to help us put a price tag on the amount of work the electrical system is performing, as well as help us install capacitors and other devices that store real energy to avoid being charged for excess apparent power. In almost all cases, the actual power used will be less than the apparent power delivered because of heat dissipation, frictional loss, work performed and other release of energy by the electrical system. Power Factor is a ratio of the actual power used by an electrical system to the apparent power delivered by the utility. Once we know power consumption, we can calculate a useful metric called “Power Factor”. Most calculations of the cost of power are based on consumption and measured by $ per kWh. Power Quality Analyzers measure consumption in units of watthours (Wh) or kilowatthours (kWh). Power demand reflects an instantaneous view of electrical usage, whereas, power consumption sums the electrical usage over the same period of time. Power consumption, similar to demand, is the “sum” of electrical usage over time. How does power consumption differ from power demand? It is important that electrical systems are supplied with enough power to meet peak periods of demand. Power demand is the amount of average electrical energy that is consumed over some period of time by a device, machine building, etc… Power Quality Analyzers, electronic instruments used to measure indicators of power quality, can average the electrical energy and display it in units of “kilowatts”. What is power demand and how do we measure it? By measuring cleanliness, consumers are able to avoid improper function, overheating and a plethora of other consequences of unclean power. By measuring demand and consumption, consumers can identify cost centers in their electrical infrastructures as well as engineer the electrical infrastructure required to meet those demands. Measuring Power Quality typically involves calculating indicators of power demand, power consumption and power cleanliness. With the introduction of new electronic technologies over the last several decades, the world has placed new and more complex demands for clean and reliable power. Poor power quality may result in improper function, overheating, accelerated wear and tear, falsely tripped circuit breakers and, in some cases, hazardous conditions. The reliability and cost of any electrical system depends greatly on the quality of the power supplied to and consumed by the system.
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