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For stevenal, OK, I can understand this situation IS current unbalance, and I would like to ask another question since you mentioned about the current unbalance cause voltage unbalance. Is there any mathematics' equation can describe the relationship between current unbalance and voltage...

For stevenal, Why you think the current unbalance is not a problem? In my opinion, if there are three single-phase load connects on a branch and their loads are different, then the three phase current would be different, which causes the phase unbalance. Also the current transmission must have...

Well, it 's just only an example, not the real situation, I do know that is a small unbalance by calculating. You're right, coffee is more important than phase unbalance, I write down this comment with drinking my ice coffee.

For waross, Did you mean that directly adjust the phase by hand (Manual processing)? Is there any equipment could automatic detect the current signal and switch the phase? But I think my thought might be too ideal.

For bacon: Yes, it is, glad to hear that you still remembered my previous question. I am actually a beginner on this topic, so I might not describe the question clearly. What my project manager ask me to do is to collect the information of the equipment or the techniques which can help to...

Hi everyone, I am collecting the information about the equipment to solve phase unbalance, but I am not sure about my search keyword is correct or not, since I could not find many information. I use the words like: phase balancer; phase shifter; phase balance device. Then, I would like to ask...

Hi guys, thank you for response, what an interesting topic! Also I saw another description between system inertia and synchronous inertia. Since syn. inertia only considered the machines with inertia and work "synchronously" with the grid, the syn. inertia should be calculated by "Hsyn = sum of...

Thanks everyone very much! Dear cranky108, about the issue of adding inertia in the grid, actually it's not the main issue I care now, but suggestion you gave is useful, I would keep in mind. Dear FPelec, do you mean that "if the generators are not-in-service or their generation are 0 MW, I...

Hi everyone, I got some questions about "System Inertia and Synchronous Inertia", while doing some study my manager asked. Q1: Some paper mentioned that they can "update the system inertia by time". But, based on the formula of calculating system inertia [Htotal = sum of (each generators'...

Hi everyone, It's been a while, and I got a question while reading the standard. Could anyone tell me the difference between "public low-voltage supply system" and "low-voltage supply system"? I asked "Dr. Chatgpt" and he/she told me that their voltage levels are the same, so I am not sure...

wcaseyharman, thank you in advance, please let me know if you got more information!!

Palletjack, could you please tell which company followed which standard to design this value (3%)? 3% as I know, some standard design this value in the area where has rich single-phase machine, so their tolerances must be high.

bacon4life, that's what I thought, I however still look for them.

Hello everyone, From last question, I asked about the standard of unbalance of both voltage and current, since my manager asked me to collect them, please check the thread "About three-phase unbalance standard". https://www.eng-tips.com/viewthread.cfm?qid=516148 Well, I got a new situation...

That's true, the grid must meet various criteria to ensure it operate safely and normally. Thank you for giving a good vision of small scale RES, I did not consider about the roof top PV system previously. My wording needs to be corrected, it is not "re-dispatching RES", it more likes...

jghrist, In your personal experience, you give a rule for the current unbalance is "not exceed 15%", right? Could you please tell the voltage level in your system? In my opinion, the tolerance seem to be too large for distribution system, or your feeder is not operated under high demand? Also...

stevenal, Load state is still investigated, so I could not give you an answer recently. However, our research focus on RES in grid in the future situation, we could not expect the penetration of RES in the future (based on gov. policy). But, if the penetration is too high, we need to design the...

Thanks each of you for the response, I am really grateful. Actually, I got the day-off from Feb.8 to Feb.14, and also I have schedule with my family, so I might not give a response in couple days. After getting back, I will read the responses and make a discussion with you. Please have a nice...

So, in your opinions, could I say that "Design the standard for voltage unbalance is enough, since the current unbalance is created by voltage unbalance."? My project focuses on the renewable energy sources, and we both know that RES connect to grid by power electronic equipment. It might...

Hello everyone, Recently, my manager asked me to collect the standard about three-phase unbalance include voltage and current. I already read some standards, like 1)IEEE std.1159, 2)IEC 61000-2-2, 3)EN 51600, 4)ANSI C84.1, 5)NEMA MG-1. However, most of them only mentioned about the limit of...