Import active energy vs. Export active energy

[machinedr]

Hi all,

My mind is a little bit confused about these two: import active energy and export active energy. We have a reactive power control relay (compensation sys.) and it says it can show these two on its display. But I need directly active energy. How these two related to total active energy? I am confused. Please help.

 

[dpc]

"active energy"? Do you mean reactive power?

 

[ScottyUK]

dpc - forward and reverse power, perhaps?

mchinedr,

Find an undergraduate electrical machines text: the four quadrants for import and export of reactive power are covered in depth in most. There are some good references in faq238-1287. You'll pick some of them up on Amazon for next to nothing. I'm not evading the question, but in a text-only forum it is much harder to explain this topic than it is to read about it. Come back with questions once you've had a look at a text book.

 

[machinedr]

Ok, thank you very much for replies. These are from four quadrant but what i need to know is something different. I mean I understand that by saying "import active power" it is saying "the active power input to the module" and "export active power" is vice versa. Am I right? The point I can't understand is that. İmport is for module right?

Thanks for answers.

 

[LSpark]

I would understnad that to mean that import active energy is input into the module (such as a motor or load centre) and export active energy is output from the module (from a generator).

 

[stevenal]

The terms are flexible, and it is up to the system designer to determine how they are used. Import can become export with an instrument transformer polarity change, and can sometimes be changed in the device setup.

 

[stevenal]

Are you asking about power or energy? I see both terms used above. Total active power at any time would be the sum of the two powers, one of them always being zero. Total energy over a period can be defined differently depending on the purpose. Might be the sum, or might be the net.

 

[machinedr]

@stevenal: It was energy.