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gardengnome747, Thanks for your information. Kiribanda and veritas, Thanks for your opinion. I agree to select by Ics. It's safer selection. However, have any guide or practice to highlight how to select CB according to Icu/Ics? Please advise, if any. Thanks again.

Dear All, There is a question I wonder to know how select the breaker. It assumed already have the calculated fault current by SKM. Which do I select the Icu or Ics accordingly? For example, the said calculated value is 42kA @480V InitSymRMS 3P. IEC breaker rating Icu/Ics = 50kA/38kA @500V...

Dear Bill, thanks for your clue, I think I figure out.

Hi everyone, there is a question need your help. 33kV underground XLPE cable, 2000mm2, the length are 20kM. If we need to consider reactive compensation, how to size/calculate the capacity of shunt reactor? Are there any textbook or standard we can refer? Thanks all.

Usually, you need to develop two scenarios, one for Utility and the other one for Generator. Then find the worst case to print on label.

Maybe you in-service some capacitors in your system.

7anoter4 and electricpete, Thanks for your excellent opinion. I also think that triplen harmonic current flow under a loop condition. Again, please advise how to get the magnitude of neutral current under unbalance condition? Should include triplen harmonic and unbalance current? Regards,

Hi, I find an image in the website accidently about the harmonic issue. This image mark the direction of triple order harmonic. So, I curious and wonder to know their direction if lost the neutral line or add grounding wire. Please find the five(5) schematic as attached and advise these...

FreddyNurk and Bill, thanks for your reply. Bill, thanks for your excellent explanation.

Hi, In 3φ4W power system like 208/120V and 416/240V, G and N wire need to take care. There are 4 connection cases between G and N wire as attached. Please advise which one is practice connection and their pros and cons. Any guideline or article that I can refer to ? Thanks for your advice. Have...

Dear davidbeach and krisys, Thanks your reply.

Dear all, Thanks for your reply. Is there any guideline for reference? ciy

Hi, Please advise when undervoltage Relay (27) Shall be trip the CB or just alarm only? What is need to concern? Is there any criteria for following? Thanks. ciy

Thanks for your reply from Evergreen1231 and cranky108. The tertiary winding is also Wye connection. I wonder which damage curve of winding should be concerned? Secondary winding? Tertiary winding?

Dear all, There is a three-winding transformer rated: 345/13.8/6.9 kV transformer; 92/54.5/37.5 MVA The impedance percentage of PS/PT/ST is 16/13/1.9%. Please advise how to draw its damage curve? What is the difference between the 2 winding and 3 winding transformer? Thanks for your help in...

Rodmcm, thanks for your great advice. I want to know how to calculate capacitor size to compensate reactive value. Does it just concern the power factor of induction generator, or need to take system condition into account, when we estimate the capacitors? Have any real practice...

Dear ALL, I met an issue need help that is how to design and plan an induction generator (IG) in chemical plant. Normally, I always find Synchronous generator (SG) in the plant. What is the main design concern between IG and SG? Is there any IG design guide or reference can lead me to...

Hi, Sometimes, I propose my quotation of power system studies to my client. They might ask me how to get the amount of price, even ask me what the basis of your quotation is. I always explain that would spend how much hours and cost per man hour(MH), so get it totally. Like this is a personal...

Dear All, Thanks for your nice advice. In my understanding, whether grounding system or ungrounding system, a good power system shall take the grounding protection into account. There is a V-V connection PT in the said CASE A scheme, but without any Grounding Potential Transformer (GPT)...

Kiribanda, Thanks for your great reply. In case of CASE A already existing, how to perform ground fault protection? All we can do just only phase fault protection, that is true? Please more advise, thanks.