Reactive power in ac circuit

Power in Resistive and Reactive AC circuits Power Factor

  1. AC circuit with a Purely Reactive load. For comparison, let's consider a simple AC circuit with a purely reactive load in the figure below. AC circuit with a purely reactive (inductive) load. Power is not dissipated in a purely reactive load. Though it is alternately absorbed from and returned to the source
  2. This quantity conveys information about the proportions of active and reactive power required by an AC system. A higher proportion of reactive power is generally considered undesirable because this reduces the efficiency of transferring AC power from source to load
  3. reactive power - imaginary inductive and capacitive power consumption in circuit The required power supply is called the apparent power and is a complex value that can be expressed in a Pythagorean triangle relationship as indicated in the figure below
  4. Home>Alternating Current> Active, Reactive, Apparent and Complex Power. Simple Explanation with formulas. Simple Explanation with formulas. Alternating Current Power factor Power System Single Phase AC Circuits Three Phase AC Circuits
  5. Reactive Power. Definition: The power which flows back and froth that mean it moves in both the direction in the circuit or react upon itself, is called Reactive Power.The reactive power is measured in kilo volt ampere reactive (kVAR) or MVAR
  6. Calculating Reactive Power in AC Circuits The reactive power is the power returned to the source by the reactive components of the circuit. This type of power is measured in Volt-Amperes-Reactive, abbreviated var. Reactive power is calculated by using the voltage and current associated with the circuit reactance

In a DC circuit, the product of volts x amps gives the power consumed in watts by the circuit. However, while this formula is also true for purely resistive AC circuits, the situation is slightly more complex in an AC circuits containing reactive components as this volt-amp product can change with frequency Active, reactive, and apparent power. In a simple alternating current (AC) circuit consisting of a source and a linear load, both the current and voltage are sinusoidal.If the load is purely resistive, the two quantities reverse their polarity at the same time 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). The combination of reactive power and true power is called apparent power, and it is the product of a circuit's voltage and current. Next: Passive Components in AC Circuits. We've covered some important topics related to AC power dissipation, and we introduced the power triangle, which is a useful tool that can help you analyze AC circuits that include reactive components. In the next page we'll continue our study of passive components in the context of AC circuit analysis The relation between active, reactive and apparent power can be expressed by representing quantities as vectors, which is also called as power triangle method as shown below. In this phasor diagram voltage is considered as reference vector. The voltage & current phasor diagram is the basis for the formation of the power triangle

Learn about power calculations in AC (alternating current) circuits. We will discuss instantaneous power and how it is calculated when the current and voltage are sinusoidal. Categor Reactive power depends on the frequency/period of the voltage's oscillation, but can also be denoted as: again including the RMS voltage, but having a phase difference in the range of 0 to 90 depending on the reactive effect of inductance and capacitance. The total power in AC circuits that we call Apparent power is equal to

Reactive power, denoted with Q, is transferred when the current and voltage are 90 degrees out of phase. In such a case, the net energy transferred in the AC circuit is equal to zero, and no real power is dissipated. Reactive power never appears in DC circuits; in AC circuits, it's linked to the reactance produced by inductors and capacitors To improve the power factor (p.f) of an AC circuit a capacitor is connected parallel to the circuit.. Active and Reactive Component of Current The active component of current is that which is in phase with applied voltage i.e For a reactive component the sinusoidal voltage across the component is in quadrature (a / phase difference) with the sinusoidal current through the component. The component alternately absorbs energy from the circuit and then returns energy to the circuit, thus a pure reactance does not dissipate power

AC Power in Reactive Circuits - EE Power

Reactive Power. Reactive Power can best be described as the quantity of unused power that is developed by reactive components, such as inductors or capacitors in an AC circuit or system. In a DC circuit, the product of volts x amps gives the power consumed in watts by the circuit In electric power transmission and distribution, volt-ampere reactive (var) is a unit of measurement of reactive power. Reactive power exists in an AC circuit when the current and voltage are not in phase. The term var was proposed by the Romanian electrical engineer Constantin Budeanu and introduced in 1930 by the IEC in Stockholm, which has.

AC - Active, Reactive and Apparent Power

10μF capacitor is connected to a 240V, 50Hz supply. Calculate the reactive current and the reactive voltamperes. 11.4 Power In The Inductive AC Circuit. Figure 11.3 contains the wave diagram from an inductive AC circuit and shows the current lagging the voltage by 90° 14: Power in AC Circuits •Average Power •Cosine Wave RMS •Power Factor + •Complex Power •Power in R, L, C •Tellegen's Theorem •Power Factor Correction •Ideal Transformer •Transformer Applications •Summary E1.1 Analysis of Circuits (2017-10213) AC Power: 14 - 3 / 11 Cosine Wave: v(t) = 5cosωt. Amplitude is V = 5V Power factor. Power factor in an ac circuit is the ratio of the real power to the apparent power. As the reactive power drawn from the network decreases, the apparent power also decreases and approaches the real power. A purely resistive ac circuit would have a perfect power factor of 1.0 with zero reactive power This course is meant to eliminate the mysticism of electrical power system calculation. Including real, reactive and complex power in analysis in AC circuits. Clear easy to understand derived formulas using only algebra and a minimum of trigonometry

Active, Reactive, Apparent and Complex Power

  1. The VA rating is the apparent power that a UPS is capable of producing, while the watt rating is the real power (or true power) it is capable of producing, as opposed to reactive power. Reactive power arises due to the effects of capacitance and inductance of components in the load to be powered by the AC circuit
  2. OC = Reactive Current. OB = Circuit Current. Power Triangle provides the relationship between the three quantities and following information. 1) Active Power P, Reactive Power Q and Apparent Power S are related as. S = P + jQ. S 2 = P 2 + Q 2. S = √(P 2 + Q 2) 2) Power Factor is defined as the cosine of angle between the voltage and current.
  3. What is actually reactive power? Negative energy flow is the same recuperation in AC circuit if one compare it to bi-directional DC or AC energy flow. Because time scale (20ms or 20 hours.
  4. Find the power factor of a circuit by entering the voltage, current, and power below. The calculator also solves the apparent power, reactive power, and estimates the size of capacitor needed to correct it
  5. 3.Apparent power (S): The total power delivered to the load is called apparent power or we can say the combination of real power and reactive power. Total power in an AC circuit, both dissipated and absorbed/returned is referred to as apparent power
  6. Reactive power: If a pure reactance, i.e. capacitive or inductive impedance, is connected to an AC circuit, the phase displacement j between the current and voltage is 90°, the current leading the voltage in the case of the capacitance, and lagging behind the voltage in the case of the inductance (as shown in the diagram below)
  7. Reactive power. Reactive power flow on the alternating current transmission system is needed to support the transfer of real power over the network. In alternating current circuits energy is stored temporarily in inductive and capacitive elements, which can result in the periodic reversal of the direction of energy flow

Active, Reactive and Apparent Power - Circuit Glob

  1. For comparison, let's consider a simple AC circuit with a purely reactive load in Figure below. AC circuit with a purely reactive (inductive) load. Power is not dissipated in a purely reactive load. Though it is alternately absorbed from and returned to the source. Note that the power alternates equally between cycles of positive and negative
  2. AC Power: A Worked Example Andrew McHutchon April 22, 2013 The voltage in a circuit is V~ = 240\0 and the impedance of the circuit at 50Hz is Z~ = 48 + j36. In the following we work through the analysis of this setup, tackling many of the calculations you will be required to make in the Cambridge 1A course
  3. In AC circuits, the power factor is the ratio of the real power that is used to do work and the apparent power that is supplied to the circuit. The power factor can get values in the range from 0 to 1. When all the power is reactive power with no real power (usually inductive load) - the power factor is 0. When all the power is real power with.
  4. The angle \$\varphi\$ is the power factor angle and \$\cos \varphi\$ = power factor. If the voltage and current are exactly in phase as with a purely resistive circuit, the power factor is 1.0 and the reactive power is 0. If the voltage and current are exactly 90 degrees out of phase as with a purely inductive or purely capacitive circuit, the.
  5. The real power P in watts (W) is equal to the voltage V in volts (V) times current I in amps (A) times the power factor (cos φ): P (W) = V (V) × I (A) × cos φ. The reactive power Q in volt-amps reactive (VAR) is equal to the voltage V in volts (V) times the current I in amps (A) time the sine of the complex power phase angle (φ)

A31. In a series circuit impedance is calculated from the values of resistance and reactance. In a parallel circuit, the values of resistive current and reactive current must be used to calculate total current (impedance current) and this value must be divided into the source voltage to calculate the impedance Actually in three phase system, the reactive power in each individual phase is not zero but sum of them at any instant is zero. Reactive power is the form of magnetic energy, flowing per unit time in an electric circuit. Its unit is VAR (Volt Ampere Reactive). This power can never be used in an AC circuit Reactive power is symbolized by the letter Q and is measured in the unit of Volt-Amps-Reactive (VAR). Total power in an AC circuit, both dissipated and absorbed/returned is referred to as apparent power. Apparent power is symbolized by the letter S and is measured in the unit of Volt-Amps (VA). These three types of power are trigonometrically. Importance of Reactive Power. Reactive power is both the problem and solution to the power system network for several reasons. It plays an important role in the electrical power system for various functions such as satisfying the reactive power requirement, improving the voltage profiles, decreasing the network loss, providing sufficient reserve to ensure system security in emergencies, and.

AC circuits are usually three-phase for electrical distribution and electrical transmission purposes. Single phase circuits are commonly used in our domestic supply system. The total power of a three-phase AC circuit is equal to three times the single phase power. So if the power in a single phase of Single Phase AC Circuits I. INTRODUCTION OBJECTIVES: • Study the phasor relationship between Voltage and Current in a single phase AC Circuit. • Study the concept of real power (P), reactive power (Q), apparent power(S) and power factor (cosΦ). • Identify a method to improve the line side power factor with the help of a capacitor bank Active vs. Reactive Power: Comparison Chart. Summary Active vs Reactive Power. In AC circuits, active power is the real power consumed by the equipment to do useful work meaning the power dissipated by a load, whereas reactive power is an imaginary power which is not used directly for work

Calculating Reactive Power in AC Circuits - tpub

The resistor consumes power, converting electrical power into heat. Again, this is easily seen by selecting the R circuit and showing power. The power waveform is only positive. In a RLC circuit, v L and v C are opposite in polarity. So the capacitor supplies leading capacitive reactive power to the lagging inductive reactive power of the inductor In this article, I provide an overview of the three types of electrical power in ac circuits: real power, reactive power and apparent power.I also explain how the three relate to each other and provide an analogy to clarify this complex relationship In electric power transmission and distribution, volt-ampere reactive (var) is a unit by which reactive power is expressed in an AC electric power system. Reactive power exists in an AC circuit when the current and voltage are not in phase. The correct symbol is var and not Var, VAr, or VAR, but all three terms are widely used, and VAR is. Reactive Power: Reactive power is an imaginary power which is delivered by capacitors and alternators. Consider the case in which the load is a pure capacitance for which Z =(1/ωC) ∠−90 . Then, θ= −90 , and we have Get More Electrical Concept And Interview Questions By Using This Link Here again, the average power is [

AC Inductive circuits. STUDY. PLAY. Three types of power in an AC circuit. True, reactive, apparent Pour power and reactive power volts times amps If the metering is done at medium voltage then the additional reactive power consumed by the transformer will also be measured. In cases like these it is important to know how much reactive power is drawn by the transformer so that it can be subtracted from the load reactive power demand A capacitor does effect the whole circuit it is applied to but in different ways other than reactance. When a circuit has a 'bad' reactive power factor there will be an imbalance of voltage and higher currents normally resulting in higher kva than required to power the inductive loads being fed No circuit is without some resistance, whether desired or not. Resistive and reactive components in an AC circuit oppose current flow. The total opposition to current flow in a circuit depends on its resistance, its reactance, and the phase relationships between them. Impedance is defined as the total opposition to current flow in a circuit.

Reactive power (Q) is the power consumed in an AC circuit because of the expansion and collapse of magnetic (inductive) and electrostatic (capacitive) fields. Reactive power is expressed in volt-amperes-reactive (VAR). Equation (9-3) is a mathematical representation for reactive power Reactive power results from delay between current and voltage. In a direct current (DC) circuit, the power is of constant intensity and can only flow in one direction. Current and voltage in alternating current (AC) circuits, on the other hand, fluctuate rapidl

Reactive Power - Basic Electronics Tutorial

Apparant power (S) is the vector sum of active power (P) and reactive power (Q). Reactive power is fundamental for the AC circuit as it builds up the electromagnetic fields in the AC equipment, and active power does the actual work Ac Motors, Generators and Power Systems Lesson 3: Ac Power in Single Phase Circuits 1 lesson 3_et332b.pptx Learning Objectives 2 lesson 3_et332b.pptx After this presentation you will be able to: Identify the components of complex power. Compute complex power given ac voltage and current

AC power - Wikipedi

  1. ate this wastage
  2. Reactive power (VAR) compensation is defined as the management of reactive power to improve the performance of ac systems. There are two aspects:- a) Load Compensation - The main objectives are to :- (i) increase the power factor of the system (ii) to balance the real power drawn from the system (iii) compensate voltage regulation (iv) to.
  3. In this example, the current to the load would be 2 amps, RMS. The power dissipated at the load would be 240 watts. Because this load is purely resistive (no reactance), the current is in phase with the voltage, and calculations look similar to that in an equivalent DC circuit
  4. s Video Lesson : Analysing an RLC series Circuit, Relationship between Voltage across RLC elements, Power in AC Circuits, Active Power, Apparent Power and Reactive Power, Active and Reactive Currents, Power Factor, and other topics
  5. Purely capacitive circuits cause reactive power with the current waveform leading the voltage wave by 90 degrees, while purely inductive circuits cause reactive power with the current waveform lagging the voltage waveform by 90 degrees. The result of this is that capacitive and inductive circuit elements tend to cancel each other out
  6. it merely stores and releases energy from reactive components. In a purely reactive circuit, all power in the circuit is imaginary and does no useful work. In a purely resistive circuit, all power is real and is dissipated from the circuit by the resistance (this is also true of motor circuits operating at 100% efficiency
  7. POWER IN AC CIRCUITS You know that in a direct current circuit the power is equal to the voltage times the current, or P = E X I. If a voltage of 100 volts applied to a circuit produces a current of 10 amperes, the power is 1000 watts

What is reactive power? Keep in mind that reactive power (KVAR) is a component of AC power, and is demanded by the load. Power generators are kind of automatically controlled by the load. When the load needs more KVAR, KVA increases (I think when you say voltage, you mean power) Average Power. Normally the average power is the power of interest in AC circuits. Since the expression for the instantaneous power . is a continuously varying one with time, the average must be obtained by integration. Averaging over one period T of the sinusoidal function will give the average power (e) What is the real power (P), the reactive power (Q), and the total apparent power (P app) drawn by the circuit? (f) Draw a phasor diagram for the power (consists of the real, reactive, and apparent power phasors). Use the real power phasor as your reference. (g) What is the power factor (PF) of the circuit? Is it leading or lagging observe and measure the real, reactive, and apparent power requirements of this load when connected to a 120 V ac, 60 Hz voltage source. Additionally, you will learn about power factor correction. As you will see in this lab, by placing a capacitor in parallel with the fan, you can reduce the reactive power required of the voltage source which wil

The guide to reactive power An npower briefing note Electricity can be either direct current (DC) or alternating current (AC). Electricity supplied from a battery will be DC but that supplied from the public electricity supply is AC. AC has the advantage that i Power in resistive and reactive AC circuits. Consider a circuit for a single-phase AC power system, where a 120 volt, 60 Hz AC voltage source is delivering power to a resistive load: (Figure below) Ac source drives a purely resistive load. In this example, the current to the load would be 2 amps, RMS

What is reactive power in an ac circuit? Why is the concept of average power used in ac circuits? When we quote average power, we do so because often on a mains feeder the power to various loads. 2. Power factor correction (PFC) in ac-dc supplies consists of using a control circuit to switch a MOSFET. It draws current through an inductor to fill in the gaps that would otherwise represent. PDF | Purpose ‐ The purpose of this paper is to suggest a polynomial complexity method for determining the range of the active and reactive power consumed in AC uncertain parameter circuits.

In AC circuit analysis, what is this power that we talk about. The main problem is that the AC voltage and current varies sinusoidally with time. Moreover the presence of circuit reactive elements like Inductor and capacitor shift the current wave with respect to voltage wave (angle of phase difference) Power in resistive and reactive AC circuits. Consider a circuit for a single-phase AC power system, where a 120 volt, 60 Hz AC voltage source is delivering power to a resistive load: In this example, the current to the load would be 2 amps, RMS Why there is not any reactive power in DC although it causes magnetic field... Answer / haydad ahmad There is no reactive power in dc circuits because reactive power is produce due to phase difference in ac circuits but which is not in dc circuits .In dc circuits V and I lies at straight line so reactive power in dc circuits is zero

True, Reactive, and Apparent Power - All About Circuits

The power factor is described as lagging this tells us that the circuit is predominantly inductive and the current lags the voltage => φ = φv - φi = 25.8° 5. Reactive Power Q We have seen that P = V rms.Irms.cos(φ) = S.cos(φ) The reactive power is defined as: Q = V rms.Irms.sin(φ) with units vars and it can readily be shown that S2 = P 2. could also argue that capacitive loads supply 'negative' reactive power which cancels out the 'positive' reactive power of inductive loads. For a generator, reactive power is usually labeled 'positive' when it is over-excited and supplying reactive power to inductive loads. If under-excited, it actually draws reactive power from an infinite bu

If an AC circuit has a lagging power factor, the way to correct for that power factor is to add a capacitor to the circuit to create leading reactive power. This leading reactive power will cancel the lagging reactive power of the load, ideally negating one another so that there is no reactive power demands placed on the source (zero net. (For an overview of reactive power in ac circuits, see Reactive Power Primer,) Voltage Control. The American National Standards Institute (ANSI) defines acceptable (Range A) and tolerable (Range B) service and utilization voltage levels in ANSI C84.1-2011, American National Standard for Electric Power Systems—Voltage Ratings (60. Written by an experienced power engineer, AC Circuits and Power Systems in Practice offers a comprehensive guide that reviews power system fundamentals and network theorems while exploring the practical aspects of equipment design and application. The author covers a wide-range of topics including basic circuit theorems, phasor diagrams, per. Capacitors in Power Systems Capacitors are used extensively in power systems to generate reactive power locally in order to correct the power factor, reduce the source current, regulate the voltage and improve system efficiency

Contemporary Electric Circuits, 2nd ed., ©Prentice-Hall, 2008 Class Notes Ch. 10 Page 1 Strangeway, Petersen, Gassert, and Lokken CHAPTER 10 Power in AC Circuits CHAPTER OUTLINE 10.1 Complex Power in Circuits with AC Signals 10.2 How to Calculate Complex Power 10.3 Complex Power Calculations in Series-Parallel Circuits Importance of reactive power. AC power supply systems produce and consume two types of powers; active and reactive power. Real power or active power is the true power given to any load. It accomplishes useful work like lighting lamps, rotating motors, etc

reactive power is used for the maximum reactive power that flows through a piece of electric network. The change of meaning is the origin of a few misconceptions that are present in almost every textbook today. This article reanalyzes the reactive power concept, identifies the present contradiction - AC Power Production and Measurement - AC Power Calculation for a Resistive Circuit. Lesson 3: Effects of Inductance and Capacitance - Inductive and Capacitive Elements in AC Circuits - Calculation of Power in an Inductive Circuit - Calculation of Power in a Capacitive Circuit. Lesson 4: Power Factor - Power in an RLC Circuit - Apparent Power. Complex power S is defined as the complex sum of the average and the reactive power S = P + j Q To distinguish the three powers S, P and Q, different units are used for each. Real power P is in watts (W), reactive power is in volt-amp reactive (VAR), and complex power is volt-amps (VA)

The Power Triangle and Power Factor - EE Power

Reactive Power Reactive power is the measure of a circuit's reactance (X). A purely reactive circuit dissipates zero real power because the power is absorbed by the circuit and returned to the AC source. This circuit results in 90 degrees phase shift between the voltage and current waveforms, as shown in Figure 2 Reactive power sources are used to vary capacitors in static systems. The response of the reactive power system is dictated by voltage control in dynamic conditions. When operating unstable AC systems, problems tend to arise because of unstable voltage and overvoltage surges. A better coordination of reactive power sources is required to. What happens to reactive power in an AC circuit that has both ideal inductors and ideal capacitors? [E5D09] A. It is dissipated as heat in the circuit B. It is repeatedly exchanged between the associated magnetic and electric fields, but is not dissipated C. It is dissipated as kinetic energy in the circuit D Which one of the following is true of AC circuits with reactive elements? A) The impedance of any one element can never exceed the total network impedance B) Depending on the frequency applied, the circuit can look either inductive or capacitive C) The magnitude of the voltage across any one element can never exceed the applied voltage D) The smaller the resistive element of a circuit, the. the apparent power, this angle is also the phase angle for the circuit concerned. Figure 12.3 shows a power triangle from a resistive and capacitive circuit, here the reactive power and apparent power are drawn above the active power because the circuit current leads the supply voltage. The reactive power is said to be leading

Active, Reactive and Apparent Power - Electronics Hu

8/30/2005 DC and AC Impedance of Reactive Elements.doc 6/7 Jim Stiles The Univ. of Kansas Dept. of EECS In other words, an unfathomably large inductor acts like an AC open circuit! As before, an unfathomably large inductor is impossible to build. However, a very large inductor will typically exhibit The combination of reactive power and true power is called apparent power, and it is the product of a circuit's voltage and current, without reference to phase angle. Apparent power is measured in the unit of Volt-Amps (VA) and is symbolized by the capital letter S O.Gopinath and T.Srinivasa Rao : Reactive Power and AC Voltage Control of LCC HVDC System with Digitally Tunable Controllable Capacitors the rectifier represents a load and it is natural that it draws some reactive power from the network just like other loads. On the other hand, from the point of view of the receiving end AC system, the inverte

In electric power transmission and distribution, volt-ampere reactive (var) is a unit by which reactive power is expressed in an AC electric power system.Reactive power exists in an AC circuit when the current and voltage are not in phase The portion of power due to stored energy, which returns to the source in each cycle, is known as reactive power. Active, reactive, and apparent power. In a simple alternating current (AC) circuit consisting of a source and a linear load, both the current and voltage are sinusoidal

01 - Instantaneous Power in AC Circuit Analysis (Electrical

The power factor of an AC electric power system is defined as the ratio active (true or real) power to apparent power, where. Active (Real or True) Power is measured in watts (W) and is the power drawn by the electrical resistance of a system doing useful wor consider that circuits perform a wide variety of functions, some where a high value of reactance is desirable, others not. But, generally speaking, unity power is the most desirable, as such, measures are taken to reduce the reactive component as much as possible

Physics - Electromagnetism - Power in AC circuits — Steemi

In an AC circuit, the product of voltage and current is expressed as volt-amperes (VA) or kilo volt-amperes (kVA) and is known as Apparent power, symbol S.In a non-inductive purely resistive circuit such as heaters, irons, kettles and filament bulbs, etc. their reactance is practically zero, and the impedance of the circuit is composed almost entirely of just resistance To my understanding, capacitors cause the current to lead the voltage which adds VARS to the circuit and inductors cause the current to lag behind the voltage which removes VARS (in AC circuits). Also, it is my understanding that VARS increase voltage. I work for one of the largest utilities in the. For the Phasors and AC Power section calculate the following for each component: θ - angle in degrees between the voltage the current. Z - total impedance of the component using ohms law. S - the apparent power in the component. Q - the reactive power in the component. P - the real power in the component To calculate power in an AC circuit using time-varying voltage and current functions. Before completing this tutorial, make sure you are familiar with instantaneous power, average power, and reactive power. Calculating average and reactive power I Calculate the average (P) and reactive (Q) power for the circuit element below

Calculating Power in AC circuit (real, reactive, correction)? Applied voltage is 600 V 50 Hz. three parallel loads are connected to the applied voltage: lights (R1) consuming 12000 W of power, a furnace (inductive load with impedance 2.4+j3.2 ohm), and a motor consuming 80000 W with power factor lagging by 0.8 Study Unit 17 Inductance in AC Circuits flashcards from 's class online, or in Brainscape's iPhone or Android app. Learn faster with spaced repetition In the AC circuit of the diesel generator set, there are two kinds of electric power supplied by the power source, one is active power and the other is reactive power. Active power is the electrical power required to keep a consumer operating normally, that is, the electrical power that converts electrical energy into othe (a) apparent power is equal to the actual power (b) reactive power is more than the apparent power (c) reactive power is more than the actual power (d) actual power is more than its reactive power Ans: c. 37. Power factor of the following circuit will be zero (a) resistance (b) inductance (c) capacitance (d) both (b) and (c) Ans: d. 38 Answer Reactive power is the rate at which en ergy is alternately stored in a magnetic or electric field and returned to the supply of an AC circuit, and is expressed in reactive volt amperes.