Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [reactive-power]

Reactive power (measured in vars) is present in a system containing reactive (inductive or capacitive) components and can be either produced or consumed by different load/generation elements. Though "imaginary", the reactive power has great physical significance and is essential to the operation of the electrical system as a whole.

Reactive power (measured in vars) is present in a system containing reactive (inductive or capacitive) components and can be either produced or consumed by different load/generation elements. Though "imaginary", the reactive power has great physical significance and is essential to the operation of the electrical system as a whole.[1]

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Why does reactive power affect voltage?

Why does reactive power influence the voltage? Suppose you have a (weak) power system with a large reactive load. If you suddenly disconnect the load, you would experience a peak in the voltage. Is there a good explanation why this happens? For…
Stewie Griffin
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Why is it desirable to inject reactive power into a transmission system?

This website explains the basics of FACTS technologies and how they can be used to exchange active and reactive power with the transmission system, namely: SSSCs - can exchange active and reactive power STATCOM - can exchange reactive power…
Blue7
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Is reactive power periodic in nature? What is the exact difference between active power, average power, and real power?

Consider an RC circuit which is supplied by a sine source $$v(t)=V_m\cdot \sin(\omega t)$$ The current through the circuit will be $$i(t)=I_m\cdot \sin(\omega t+\phi) \\ \phi=\arctan \left(\dfrac{1}{\omega RC} \right)$$ The instantaneous power…
Sangeerth Prabakar
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How do reactive currents cause power transfer?

I read in 'The Art of Electronics': Power factor is a serious matter in large-scale electrical power distribution, because reactive currents don't result in useful power being delivered to the load, but cost the power company plenty in terms of I2R…
STATER
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Why / how does reactive power help improve voltage quality?

This question is related to my previous question that Olin provided a great answer to. Note that this question is about transmission and distribution systems, not electronics. I believe the claims I make in the question are known to most power…
Stewie Griffin
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What is the significance of UPS output power factor?

A UPS's output rating is shown as 2000VA/1800W. I understand that the power factor here is 0.9, but the device or load I will connect to the UPS might have pf<0.9 or pf=1 (for light bulb.) From my understanding, the real and reactive power will vary…
Md. Toufik Zaman
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When transformer rating is in kVA, why load is mentioned in WATTS?

The transformer rating is given in kVA, but the load connected is always considered in watts. Why? Eventhough, the load active power is represented in watts it has some reactive power, right? Is the total power consumed by load (active + reactive) …
akhil
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Why does reactive power injection mitigate sagging grid voltage?

I understand that reactive power injection can be used by generators to support the grid voltage when sagging, but I’ve never understood why this works. I thought it could be charging transmission line capacitance or something, but I can’t make…
Mitchell Easley
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Reactive power in AC circuit

What is meant by reactive power in AC circuits? Power is joules per second. Real power is the energy dissipated in the resistor per second. What is meant by the reactive power? Does this mean the energy being stored in capacitor and inductor per…
Alex
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How to pick a capacitor to adjust loop compensation caused by reactive load?

I do wish to add a voltage regulator between a Li-Ion battery pack and a 36V 220W rated mid drive pedalling assist motor with integrated controller. The caps of that controller have a 63V rating. That pedal-assist motor has an unloaded current draw…
Pro Backup
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Using Reactive vs Real Power to Manage Distribution System Voltages

This is my first post. The introduction of photovoltaics (PV) on the electrical distribution system creates changes to real power, resulting in voltage fluctuations. Those voltage fluctuations can be mitigated in two ways: a) real power b)…
user116801
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What is reactive Power and how it is generated and what is its source?

Many people, including me are good with dealing with real and reactive power in power flow systems, but still has question at the end of the day: What is reactive power and how it is generated or what is its source? After taking few course in power…
dr3patel
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Reducing reactive power by using a resistor

I have a school exercise that goes like this: Voltage is 230V. Frequency is 50Hz. Inductor is 400mH. How big of a resistor should be added with the inductor (in a series) to reduce reactive power by 75%? (The correct answer is apparently 218…
norepine phrine
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Simulate a motor with resistor and inductor

I want to simulate a motor with a resistor and inductor. It means I want to connect a resistor and inductor to 1-phase or 3-phase instead of a motor. For achieving this goal I have to measure both active and reactive power and calculate the value of…
Hamed P
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Why is power factor such a meaningful quantity?

In my current electrical engineering course the concept of power factor has been a large topic, defined as the ratio of real power to apparent power. It is a measure of resistive power consumption in a circuit. Other kind of loss present in the…
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