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This is because reactive power concept is completely different from active(real) power,
That is when we talk about active (real) power, we deal with two terms :
The average value, and the instantaneous value.
Both has significant values; let's say the average value is 5kw, where the instantaneous value maybe 2kw or 6kw, etc...
On the otherhand, reactive power has always a Zero average value, and a different significant instantaneous values, but since the instantaneous value is difficult to measure, we always take the maximum instantaneous value of reactive power and deal with it as a textbook terminology (Reactive power) which is symbolized as Q and equals V I sintheta.
And for the same reason (difficult to measure instantaneous value ) we easily deal with the average value of the active power other than the instantaneous value.
As a brief:
(Active power) symbolized P or known sometimes as real power equals V I cos theta
represents the average value.
(Reactive power) symbolized Q equals V I sin theta represents maximum instantaneous value.
Someone can ask!
Why not to take the maximum instantaneous value of average power such as reactive power as a terminology?
Easily , why not to unites the two concepts ?!
This is the answer of our main question (Why reactive power is so confusing for engineers?)
This is easily because ,there is no useful meaning of using the instantaneous value for the active power, because it is a real produced power goes in one direction from source to load, where the average reactive power is always zero valued, since it goes back and forth in the network, and we are forced to deal with it in some way as an indication value and give it a unique terminology to express it as a fact that we cannot skip.
In other words, you cannot compare two different things; apple and banana! Each one has a different taste.
I hope that I answered the question, and dislodged some dust about this confusing concept, even I didn't take the boring mathematical path.
Wiki User
∙ 13y ago
Wiki User
∙ 13y agoThis is because reactive power concept is completely different from active(real) power,
That is when we talk about active (real) power, we deal with two terms :
The average value, and the instantaneous value.
Both has significant values; let's say the average value is 5kw, where the instantaneous value maybe 2kw or 6kw, etc...
On the otherhand, reactive power has always a Zero average value, and a different significant instantaneous values, but since the instantaneous value is difficult to measure, we always take the maximum instantaneous value of reactive power and deal with it as a textbook terminology (Reactive power) which is symbolized as Q and equals V I sintheta.
And for the same reason (difficult to measure instantaneous value ) we easily deal with the average value of the active power other than the instantaneous value.
As a brief:
(Active power) symbolized P or known sometimes as real power equals V I cos theta
represents the average value.
(Reactive power) symbolized Q equals V I sin theta represents maximum instantaneous value.
Someone can ask!
Why not to take the maximum instantaneous value of active power such as reactive power as a terminology?
Easily , why not to unites the two concepts ?!
This is the answer of our main question (Why reactive power is so confusing to understand?)
This is easily because ,there is no useful meaning of using the instantaneous value for the active power, because it is a real produced power goes in one direction from source to load, where the average reactive power is always zero valued, since it goes back and forth in the network, and we are forced to deal with it in some way as an indication value and give it a unique terminology to express it as a fact that we cannot skip.
In other words, you cannot compare two different things; apple and banana! Each one has a different taste.
I hope that I answered the question, and dislodged some dust about this confusing concept, even I didn't take the boring mathematical path.
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Importance of reactive power?
So as to start the motor because reactive power helps create the magnetic fields in rotor.
What kind of power is required to supply both resistive and reactive components of a load or loads?
You may be fishing for the answer "AC" or "alternating current", sinceno reactive component of power is developed in response to DC.AnswerSince true power (in watts) is associated with resistive components, and reactive power (in reactive volt amperes) is associated with reactive loads, the vector-sum of these is called apparent power (in volt amperes). So the answer you are looking for is apparent power.
How reactive power contributes to additional losses?
Reactive power is well known as that component which is shunted back and forth from the source to the load over the AC cycle. However, this does not mean the system has no reactive power losses. In fact they would be quite high. Loss is always measured with respect to load and not the source. When we term it reactive power loss, it is not the amount of power taken away from the source and not returned. That way, there would absolutely be no reactive loss at all because all the energy stored in the reactive elements are anyway returned. The idea is after all to provide the power to the load. So, the loss represents the amount of power unable to reach the load. The power lines are not purely resistive. They comprise considerable level of reactive elements especially line inductance.Now, the active power which actually runs the load is never a separate entity. It co-exists with reactive power because the reactive (more so inductive) components of the load need to be energized in order to power the load. Reactive power loss is thus that amount of power which is deficient or 'not supplied' to the storage (reactive) elements of the load because of the reactive elements on the line. Thus the loss is always to be visualized in terms of load. That is why the complete return of reactive power to the source in the negative cycle has got nothing to do with loss understanding actually.Hope this helps!
Why reactive power flow is undesired?
Reactive power is useless part of the energy supplied. A minimum value of reactive power is always required to keep the voltage constant and supply the useful active power. In order to understand the concept completely, do refer PV and QV curves which explains the interdependency of active power, reactive power and voltage.
How do you find whether it is inductor or capacitor if only power factor is given?
in case of inductor or capacitor power factor is always zero.as power factor is cosine of phase angle between voltage and current. in case of inductor and capacitor phase angle between voltage and current is 90 so it become zero so if given power factor is zero then it can be inductor or capacitor.
Importance of reactive power?
So as to start the motor because reactive power helps create the magnetic fields in rotor.
Is reactive power a vector or scalar?
I am not sure what exactly you mean by "reactive power" (I guess you mean electrical reactive power), but power is the ratio of energy for a period of time. So that makes power (and reactive power as well) a scalar, since you can describe it with only one number. The fact that electrical reactive power is drawn on a XY plane, should not confuse you.
What kind of power is required to supply both resistive and reactive components of a load or loads?
You may be fishing for the answer "AC" or "alternating current", sinceno reactive component of power is developed in response to DC.AnswerSince true power (in watts) is associated with resistive components, and reactive power (in reactive volt amperes) is associated with reactive loads, the vector-sum of these is called apparent power (in volt amperes). So the answer you are looking for is apparent power.
How reactive power contributes to additional losses?
Reactive power is well known as that component which is shunted back and forth from the source to the load over the AC cycle. However, this does not mean the system has no reactive power losses. In fact they would be quite high. Loss is always measured with respect to load and not the source. When we term it reactive power loss, it is not the amount of power taken away from the source and not returned. That way, there would absolutely be no reactive loss at all because all the energy stored in the reactive elements are anyway returned. The idea is after all to provide the power to the load. So, the loss represents the amount of power unable to reach the load. The power lines are not purely resistive. They comprise considerable level of reactive elements especially line inductance.Now, the active power which actually runs the load is never a separate entity. It co-exists with reactive power because the reactive (more so inductive) components of the load need to be energized in order to power the load. Reactive power loss is thus that amount of power which is deficient or 'not supplied' to the storage (reactive) elements of the load because of the reactive elements on the line. Thus the loss is always to be visualized in terms of load. That is why the complete return of reactive power to the source in the negative cycle has got nothing to do with loss understanding actually.Hope this helps!
What is the relationship between voltage instability and reactive power?
Voltage is a function of reactive power becouse normally X is greater than R between 2 nodes, so the voltage of a line is determined by X, wich on the other hand depends from reactive power Q
Why reactive power flow is undesired?
Reactive power is useless part of the energy supplied. A minimum value of reactive power is always required to keep the voltage constant and supply the useful active power. In order to understand the concept completely, do refer PV and QV curves which explains the interdependency of active power, reactive power and voltage.
How do you find whether it is inductor or capacitor if only power factor is given?
in case of inductor or capacitor power factor is always zero.as power factor is cosine of phase angle between voltage and current. in case of inductor and capacitor phase angle between voltage and current is 90 so it become zero so if given power factor is zero then it can be inductor or capacitor.
What are advantages of reactive power?
Real power is power that is used to do work. This is the power a light bulb uses to glow. Reactive power is power that is stored in one part of the AC voltage wave, and released in another. This causes the power to appear as a phase shift, and is generally caused by inductive or capactive loads. With regard to the power system, you can also get reactive power flowing due to unequal source voltages. Under these conditions, the apparent impedance of one source to the other will appear reactive/inductive, resulting in reactive power flow.
Why No reactive power on DC circuit don't give answer as W equals 23.14fL as f is zero Xc as infinity and Xl as zero?
Reactive power shows up in AC when the voltage and current waves aren't in sync. In DC you don't have waves, so you don't have reactive power. That's as simply as I can put it.
What are the powers of argon?
It is inert and so has the power to preserve highly reactive substances from reacting with things. It is for this reason that the extremely reactive metal, caesium, is stored in argon.
How can improve the power factor?
To increase capacitive load and decrease inductive loadAnswerThe most common method is to add a capacitor, or a capacitor bank, in parallel with the load. In practise, the reactive power of the capacitor (they are not rated in farads, but in reactive volt amperes) must be a little short of being equal to the reactive power of the load, so that the power factor approaches, but does not equal, unity.
Breifly explain about reactive power in electric circuits?
Reactive power is opposite to Active power. The vector sum of these two powers is apprant power. So reactive power is vector difference between Apprant power & actual power given by Reactive power= Root of (difference between squares of apprant & active power). It is lost power of the system on which power factor depends.
