MVA Method Load Flow Calculation

11 Responses

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1. tiong says

   Quoted” 1. Motor MVAs are equal to the rated Equivalent MVAs.”

   I wish to confirm that Motor MVAs is the short circuit MVA please? Thank you

   August 16, 2010, 3:36 PM
2. Ver says

   Hi Tiong,

   Motor MVAs in load flow calculation is the rated motor MVA, not the short circuit MVA

   August 16, 2010, 4:18 PM
3. artem says

   @ 11kv bus as per mva diagram,
   upstream values mva are 67.33 (transfo. 2) and 44.94 (motor 5mva)
   downstream values mva are 8.55 (transfo. 1) and 3.94 (generator side)..
   Please help me to explain sir how did these values came. How to perform this calculation…Thank you.

   February 1, 2011, 6:39 PM
4. Ver says

   Hi artem,

   Here is how the values were taken.

   Upstream Values:
   

   
   The sum will be:
   

   Downstream Values:
   

   

   The sum will be:
   

   Hope this helps.

   February 2, 2011, 4:47 AM
5. artem says

   exactly sir ver, this helps a lot. thank you very much..mabuhay ka and god bless.

   February 2, 2011, 10:56 AM
6. artem says

   I’m sorry sir Ver but i have additional query about the voltage dip or voltage drop upon starting the motor 150kva on the system which draws a power of 0.9 MVA..I have a result by hand calculations at 400V Bus: 77.22%, at 6.6kV: 87.72%, at 11kV: 89.28% which is a little different result on your MVA Diagram as shown that at 400V Bus: 76.7% (shown calculation), at 6.6kV Bus: 80.6%, at 11kV Bus: 90% and 33kV Bus: 96.6%.
   Please help me sir, how did you perform this calculations.. thank you..

   February 2, 2011, 1:28 PM
7. Ver says

   Hi artem,

   I have updated the article. I hope it will be much clearer at this time.

   Thanks

   February 2, 2011, 8:25 PM
8. artem says

   I salute you sir for sharing your knowledge and expertise, thank you very much..god bless.

   February 3, 2011, 10:36 AM
9. orlyboy says

   Sir,

   What is meant by MVA?
   Is it Mega Volt Ampere or Mean Value Analysis?

   Regards,
   Orlyboy

   March 20, 2012, 12:20 PM
10. orlyboy says

    Sir,
    How come the upstream value at 400V bus is 1.65 MVA?
    As in the figure shows (1/0.9)+(1/0.15)+(1/0.596) = 9.4556
    1/9.4556 is approximately 0.105757.

    How come it is 1.65?

    Kindly explain

    March 25, 2012, 12:21 AM
11. Ver says

    @orlyboy,

    as they load are in parallel, the MVAs should be added. The answer was correct, it was a typo on the formula. Thanks for picking that up.

    March 25, 2012, 5:50 AM

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