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Topic: Reactive power

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	electric power: Reactive Power — FactMonster.com
		Reactive power is significant because it must be provided and maintained to insure continuous, steady voltage on transmission networks.
		Reactive power thus is produced for maintenance of the system and not for end-use consumption.
		Power losses incurred in transmission from heat and electromagnetic emissions are included in the total reactive power requirement as are the needs of power hungry devices, such as electric motors, electromagnetic generators, and alternators.
	www.factmonster.com /ce6/sci/A0930671.html (298 words)

	Automatic voltage control circuit by using reactive power - Patent 5349283
		reactive power control means connected to said comparing means for controlling reactive power due to variations of said load according to an output from said comparator.
		Here, if a power factor (Cos.theta.) of the load is low, the reactive power is increased in the low pass filter compared with the power consumption of the load and, at the same time, the magnitude of the output power is increased and generates distorted voltage waves.
		During the time span from the time t0 to the time t1, the power is supplied from the power source terminal to the load, and during the time span from the time t1 to the time t2, the power is recurred from the load to the power terminal.
	www.freepatentsonline.com /5349283.html (3749 words)

	Active & Reactive Power :: Blocks (SimPowerSystems)
		The Active and Reactive Power block measures the active power P and reactive power Q associated with a periodic voltage-current pair that can contain harmonics.
		The output is a vector [P Q] of the active and reactive powers.
		The active power computed from the primary voltage and current is measured by an Active and Reactive Power block.
	www.mathworks.com /access/helpdesk/help/toolbox/physmod/powersys/ref/activereactivepower.html (328 words)

	Lessons In Electric Circuits -- Volume II (AC) - Chapter 11
		Power merely absorbed and returned in load due to its reactive properties is referred to as reactive power.
		Reactive power is symbolized by the letter Q and is measured in the unit of Volt-Amps-Reactive (VAR).
		Power factor can be an important aspect to consider in an AC circuit, because any power factor less than 1 means that the circuit's wiring has to carry more current than what would be necessary with zero reactance in the circuit to deliver the same amount of (true) power to the resistive load.
	www.ibiblio.org /obp/electricCircuits/AC/AC_11.html (3514 words)

	power, electric. The Columbia Encyclopedia, Sixth Edition. 2001-05
		Reactive power is a concept used by engineers to describe the loss of power in a system arising from the production of electric and magnetic fields.
		Reactive power is significant because it must be provided and maintained to insure continuous, steady voltage on transmission networks.
		Power losses incurred in transmission from heat and electromagnetic emissions are included in the total reactive power requirement as are the needs of power hungry devices, such as electric motors, electromagnetic generators, and alternators.
	www.bartleby.com /65/po/power-el.html (1570 words)

	POWER AND POWER FACTOR IN AN AC CIRCUIT
		Reactive power represents the energy alternately stored and returned to the system by capacitors and/or inductors.Although reactive power does not produce useful work, it still needs to be generated and distributed to provide sufficient true power to enable electrical processes to run.
		Power factor is the ratio of true power to apparent power in an AC circuit.
		Power factor is the ratio between the KW and the KVA drawn by an electrical load where the KW is the actual load power and the KVA is the apparent load power.
	www.geocities.com /vijayakumar777/powerfactor/powerfactor.html (4198 words)

	Brainboost - reactive power (Site not responding. Last check: )
		The mathematical symbol for reactive power is (unfortunately) the capital letter Q The actual amount of power being used, or dissipated, in a circuit is called true power -, and it is measured in watts (symbolized by the capital letter P, as always)..
		Reactive power is generated in two cases: when the load current and the mains voltage are out of phase (that is, the load is inductive or capacitive) or when the load is non - linear..
		Reactive power is an integral aspect of - the physics of electricity together with real power, current and voltage, - and is treated by FERC as a critical ancillary service for procurement - purposes..
	www.brainboost.com /search.asp?Q=reactive+power&lfmq=1 (674 words)

	Spartanburg SC \| GoUpstate.com \| Spartanburg Herald-Journal (Site not responding. Last check: )
		Informally, the term 'power' is also used to refer to the amount of power used over a unit of time, in which case it is measured in watt-hours.
		The portion of power flow that, averaged over a complete cycle of the AC waveform, results in net transfer of energy in one direction is known as real power.
		By convention, capacitors are said to generate reactive power whilst inductors are said to consume it (this probably comes from the fact that most real-life loads are inductive and so reactive power has to be supplied to them from power factor correction capacitors).
	www.goupstate.com /apps/pbcs.dll/section?category=NEWS&template=wiki&text=electric_power (936 words)

	The Business Scene
		Reactive power is provided, on the one hand, by capacitors, which have low purchase costs, typically provide relatively coarse control of steady-state reactive power production, and have nearly zero operating costs.
		While reactive compensation is used extensively by most utilities, this philosophy goes further by coordinating generators and nearby transmission system capacitors to ensure that generator power factor is close to unity under normal conditions, with voltage profiles maintained fairly flat across the system and despite varying load conditions.
		Putting the reactive power philosophy of Nedwick, Mistr, and Croasdale of the mid-1990s together with the energy markets of the mid-2000s requires transmission and distribution providers to install sufficient capacitive compensation and to coordinate switching of capacitors to maintain unity power factor from generators and unity power factor loading from distribution feeders.
	www.ieee.org /organizations/pes/public/2004/nov/pesbusiness.html (2020 words)

	Power Factor Correction
		The power triangle shown in figure 1, is the simplest way to understand the effects of reactive power.
		The reactive power, or magnetizing power, (represented by the vertical leg of the upper or lower triangle) is the power required to produce the magnetic fields to enable the real work to be done.
		Reactive power is normally supplied by generators, capacitors and synchronous motors.
	www.nepsi.com /powerfactor.htm (984 words)

	Knowledge Problem: EXPLAINING REACTIVE POWER
		One is from a staff presentation at December 15's regular FERC meeting, where the presenter said that reactive power is like the bouncing up and down that happens when you walk on a trampoline.
		Those twists are reactive power, which helps propel the real power through to its ultimate goal, which is delivery to the user.
		In electric power, the counterintuitive thing about reactive power is the idea that you have to use some power along the path to balance the flow of electrons and the circuits.
	www.knowledgeproblem.com /archives/001070.html (737 words)

	Inside PQ
		Demand for reactive power was unusually high because of a large volume of long-distance transmissions streaming through Ohio to areas, including Canada, than was needed to import power to meet local demand.
		Reactive power is necessary to maintain the voltage to deliver active power through transmission lines.
		Power monitoring data captured at numerous locations across the affected area was useful in understanding the full cascade of events, notably the escalating series of voltage sags, as shown in the accompanying recorded plots.
	ecmweb.com /powerquality/electric_getting_bottom_aug (1235 words)

	Filter Power Factor Correction ICs (Site not responding. Last check: )
		With a resistive load, the reactive power is zero and the apparent power equals the real power and the power factor is unity, or 100%.
		In order for the converter to achieve power factor correction over the entire range of input line voltages, the converter in the PFC circuit must be designed so that the output voltage is greater than the peak of the input line voltage.
		Power converters are either Class A or Class D, depending upon the shape of the input current waveform.
	power.elecdesign.com /products/dsp_filter.cfm?stylename=blue§ionname=&categoryID=37 (2602 words)

	Standard 1459-2000: A New Way to Measure Power
		Reactive power (Q), measured in vars, is the power associated with the component of the current that is out-of-phase (in quadrature) with the voltage.
		In sinusoidal situations, power factor is equal to the cosine of the angle between the voltage and current (cosθ).
		The standard breaks the power measurements into components that can characterize three things: the useful real power delivered to the load, the reactive power that can be compensated with conventional power factor correction, and the power components that require other methods of compensation (such as active filters).
	powerquality.com /mag/power_standard_new_measure (2029 words)

	REACTIVE POWER
		The electrical power that oscillates between the magnetic field of an inductor and the electrical field of a capacitor.
		Reactive power is never converted to non-electrical power.
		potencia reactiva (idle power, wattless power), potencia aparente (apparent power, idle power, wattless power), energía reactiva.
	www.websters-online-dictionary.org /definition/english/re/reactive+power.html (380 words)

	What is VAR Management?
		Reactive power performs NO real work and is often associated with power that is converted to magnetic fields such as in motors.
		The effect of this is that even though the load is not using this reactive power, the higher current resulting from the low power factor loads will put a strain on the electrical transmission and distribution system and may lead to equipment failure.
		Also, the power generating capacity of generators is reduced due to the VARs that need to be supplied, or power factor correction capacitors need to be applied to improve the power factor and increase generation capacity.
	www.sandc.com /webzine/041502_1.asp (677 words)

	The Origin of Balanced Power
		Balanced power is a revolutionary concept rapidly approaching its day of reckoning as more and more experts in the field are educating themselves in its theory, effectiveness and in its simplicity.
		Reactive current is basically capacitively discharged energy that is keyed to a modulating AC source -- a "backwash" of non-active power.
		In tandem, reactive current times reactive voltage equals reactive power or "KVAR" (kilovolt-amperes reactive.) There is how a reactive voltage potential presents itself in the grounding system of an AC circuit -- via the neutral-to-ground connection at the AC mains.
	www.equitech.com /articles/origin.html (2045 words)

	Power Factor Correction Concepts
		This Apparent Power (VA) has two components; one is the Active Power (W) actually being consumed by the lamp for illuminating it, and the other is the Reactive Power (VAr) feeding the electromagnetic circuit of the control gear.
		Power factor is the ratio of Active Power (W) to the Apparent Power (VA) (Figure 1).
		The leading power factor on the first ballast, in conjunction with the lagging power factor of the second ballast, brings the total power factor to near unity.
	www.ambercaps.com /lighting/power_factor_correction_concepts.htm (684 words)

	The Oil Drum \| ASPO-USA: Support for Global Energy Flow modelling and a Net Energy database
		Reactive power occurs when the voltage and current don't go up and down together in the AC frequency cycle, i.e.
		Often wind generators can't provide this reactive power or are too far away to be effective.It is a strange concept to get your head around and is sometime called phantom power.
		I was first exposed to the complexities of reactive power, phase balancing, voltage and frequency controls etc when I converted onto B727 aircraft many years ago and have had to go back to the books to refresh my memory.
	www.theoildrum.com /comments/2006/10/31/144929/65/35 (1020 words)

	KVAR Energy Savings, Inc. - Power Factor Optimization - Save Money (Site not responding. Last check: )
		Since this reactive current component no longer travels through the conductor line from the generator to the load, it does not travel through the impedances in the line conductor.
		Since this reactive current no longer flows through the line impedances, there is less heating of the line, less losses (in the form of heat), and less voltage drop across these in - line impedances (which reduces the overall voltage drop from generator to load).
		The reactive current of the KVAR UNIT is 180 degrees out of phase with the reactive current of the inductance.
	kvarnrg.com /whatiselectricity/power_factor_optimization.htm (1933 words)

	Power Supplies
		Pulsed power for the magnets (the central solenoid, poloidal field, and correction coils) and the plasma heating system needs to be delivered in addition.
		The high level of reactive power means that a reactive power compensation system needs to be used.
		Active power is limited to 500 MW peak with a peak derivative of 200 MW/s and maximum step changes of 60 MW.
	www.iter.org /power.htm (212 words)

	A Primer on Power Factor Correction
		A power triangle is used to represent the proportion and calculate the reactive power, using the Pythagorean Theorem (Fig.
		So power factor is the proportion of power converted into useful work to the total power consumed by the loads or delivered by the power source.
		If the reactive power requirement for the capacitor bank, as calculated using Equation B, is greater than the average value previously calculated using Equation A, then the capacitor bank sized for the average value won't be sufficient for compensating the reactive power of the load when the active power reaches its maximum value.
	bg.ecmweb.com /ar/electric_primer_power_factor (2417 words)

	Reactive Power: Will a Market Ever Evolve? - Science - RedOrbit (Site not responding. Last check: )
		That flout was no one-time event.Voltage collapses caused by a shortage of reactive power also led to two major flouts in the U.S. in 1996, as well as contributing to flouts in Canada, Denmark, England, France, Italy, Japan, and Sweden in other years.
		While ensuring enough reactive power is a matter of national and regional concern, it is essentially a local problem.
		Reactive power doesn't travel long distances and needs to be available near load centers.
	www.redorbit.com /news/science/429790/reactive_power_will_a_market_ever_evolve/index.html?source=r_science (1783 words)

	96 FERC Wants Those Who Benefit from Reactive Power to Pay, Restructuring Today (Site not responding. Last check: )
		FERC wants all reactive power suppliers to be treated equally and it wants those who supply reactive power to be paid by those who benefit.
		Cost-of-service encourages the grid owner to build reactive power units, the report concluded, even though it might be cheaper to buy it from another source.
		Reactive power doesn’t live long on the grid and often must be located near where it’s needed and where few reactive power generators are located.
	www.bluefish.org /reactive.htm (376 words)

	Power Factor power quality
		Power factor is an indicator of the health or efficiency of your power distribution system.
		Reactive power is stored and released by inductance and capacitance elements in a power system.
		Reactive power is very important to the proper functioning of electrical equipment.
	www.energyconsultants.org /power_factor.htm (557 words)

	TXU Electric Delivery - Electricity - Metering Services (Site not responding. Last check: )
		Power factor is a measure of how efficiently electricity is being used.
		Reactive Power - Inductive load, such as motors, compressors etc. require reactive power to generate and sustain a magnetic field in order to operate.
		The power factor that will be used is the average power factor for the 15 minutes during the peak kW demand.
	www.oncorgroup.com /electricity/metering/power_factor/default.asp (487 words)

	Balanced Power from Equi=Tech
		In a balanced power system, the voltage to ground is only half of that (60 V.) But with at trick called inverse phasing, the normal 120 volts that audio and video equipment requires is still present between the two main wires in the power circuit.
		The term for this mirror image power topology between the two mains is "inversely phased." Balanced power consists of two 60-volts to ground AC conductors that are inversely phased.
		Note in the illustration that reactive currents in the neutral conductor are connected to ground and therefore also present in the ground wires and equipment chassis as well as all of the grounded shields in a/v cables.
	www.equitech.com /articles/widescreen.html (1810 words)

	Calculating Reactive Power in AC Circuits
		The reactive power is the power returned to the source by the reactive components of the circuit.
		Reactive power is calculated by using the voltage and current associated with the circuit reactance.
		Another way to calculate reactive power is to calculate the inductive power and capacitive power and subtract the smaller from the larger.
	www.tpub.com /neets/book2/4h.htm (193 words)

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