Reactive Power Comp: Understand, Compensate & Why Needed

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Reactive power is generated when AC voltage and current are phase-shifted by 90°, resulting in alternating positive and negative power that averages to zero over a full cycle. Reactive power compensation involves balancing reactive loads with capacitive loads to prevent the transmission of reactive power through the grid. This compensation is essential as it reduces reactive current, which causes heating in transmission lines and leads to energy losses. The discussion highlights the importance of understanding reactive power for engineers, particularly those transitioning from other fields, such as communication engineering, to power distribution. A solid grasp of concepts like VAR compensation is crucial for effectively managing low-voltage grids.
DjMadness
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Hello,

How can Reactive power be physically understood?

What is Reactive power compensation?

Why is reactive power compensation needed?

Thanks
 
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DjMadness said:
How can Reactive power be physically understood?
Reactive power is created when ac-voltage and ac-current are phase-shifted 90°. So the power is positive for one half period and negative for the next half period. Thus the resulting power for a whole period will become zero. Reactive power cannot accumulate energy.
DjMadness said:
What is Reactive power compensation?
Reactive power can be positive or negative. A reactance consumes reactive power and a capacitance produces reactive power. So if you have a reactive load, resulting in consumption of reactive power, you can just add a capacitive load, that produces the same reactive power ( with opposite sign ). In this way the grid doesn't have to transmit any reactive power. The reactive power has been compensated.
DjMadness said:
Why is reactive power compensation needed?
Because reactive current heats transmission lines due to copper losses. When reactive power is compensated, the reactive current will be reduced, and thus the total amount of current. Thereby energy ( losses ) is saved.
 
Dj

can you give a clue as to your background ?Hesch gave a good answer for a beginning student seeking understanding of the basic concept.

A newbie engineer trying to figure out how to adjust var compensation for a power station voltage regulator might need a different approach to his question.

NOT being a wise guy, but - "Who wants to know ? "
 
jim hardy said:
Dj

can you give a clue as to your background ?Hesch gave a good answer for a beginning student seeking understanding of the basic concept.

A newbie engineer trying to figure out how to adjust var compensation for a power station voltage regulator might need a different approach to his question.

NOT being a wise guy, but - "Who wants to know ? "
Dear Mr. Jim

I`m a newbie engineer [M.S In Electrical Engineering] that has been working for years in communication areas [mainly PSTN].
I had divorced power electrical engineering/simulation/different approaches to work on mV embedded systems mainly focused on automation [micro-controllers].
Recently I found interest on working on LV distribution substations, especially focusing on VAR compensation.

As you can see, there is a huge gap between theoretical knowledge [M.S] and applied understanding of different engineering fields.

What I have intention to do is to program a processor in order to [smartly] compensate VAR on L.V grids.
First I just need to have a powerful background over all these titles, of VAR, compensation, etc...
 
Many Valued Algebra? Public Switched Telephone Network?
You're very high tech - last telephony i worked on was old Automatic Electric PAX with mechanical relays, clackety-clack ...

Hesch is good explainer.

Surely you remember introductory AC circuits course - phasor notation, power = VIcosθ et al...

wikipedia has a decent review at https://en.wikipedia.org/wiki/Power_factor

refresh what they are
maybe we can help you with how they get pushed around
i was in a power plant , no significant substation experience
but PF has several "old hands" on board .
 
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I am trying to understand how transferring electric from the powerplant to my house is more effective using high voltage. The suggested explanation that the current is equal to the power supply divided by the voltage, and hence higher voltage leads to lower current and as a result to a lower power loss on the conductives is very confusing me. I know that the current is determined by the voltage and the resistance, and not by a power capability - which defines a limit to the allowable...

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