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Generator Neutral Grounding

01/21/2017 8:47 AM

a 15MW,6.6KV generator neutral is grounded through 30KVA,6.6KV/200V transformer to limit fault current to 25A. any idea what will be the secondary loading resistor value and the grounding transformer impedence referred to any side.

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#1

Re: generator neutral grounding

01/21/2017 9:34 AM

Do your own homework. CR4 is not a homework cheat site; however, if you have questions about understanding concepts or how a portion of a problem is derived, these types of questions will be accepted.

Maybe if you read some of the many websites that are available you could gain some real knowledge instead of just getting the answers to your test questions.

Unraveling the Confusion over Generator Power and Neutral ...

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#2
In reply to #1

Re: generator neutral grounding

01/21/2017 10:04 AM

You're getting soft lyn! After castigating the OP, your link pretty much answers his question, as far as I can tell

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#3
In reply to #2

Re: generator neutral grounding

01/21/2017 10:15 AM

Well, I wouldn't want anyone to think I was a big meanie.

This particular poster doesn't want to do any of their own work.

They bring elementary questions with obvious answers here and expect the forum to spoon feed the answers bo them so they don't have to do any work.

If they're a student, they should be failed.

If they're someone's employee, they should be fired.

You would think that since joining on 07/05/2011 this person might have learned something.

All they've learned is how to come here and get the forum to do their work.

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#4

Re: Generator Neutral Grounding

01/21/2017 10:27 AM

Yes, but you should be capable of applying Ohms Law yourself!!!!!

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#5

Re: Generator Neutral Grounding

01/21/2017 1:27 PM

coolyaar, please, do all of us a great big favour and find a new occupation!

Going on previous posts you are a danger to humanity.

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#6
In reply to #5

Re: Generator Neutral Grounding

01/21/2017 3:54 PM

respect your views but my boss does not think so

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#7
In reply to #6

Re: Generator Neutral Grounding

01/21/2017 3:58 PM

Does your boss know that you ask anonymous strangers to do your job for you?

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#8
In reply to #7

Re: Generator Neutral Grounding

01/21/2017 4:38 PM

hm.he will never mind

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#9
In reply to #8

Re: Generator Neutral Grounding

01/21/2017 5:02 PM

So you admit that you are incompetent and devoid of professional ethics and that your boss does not care that you are a fraud and you are dealing with lethal electrical power?

Where do you work? What is your company name?

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#10

Re: Generator Neutral Grounding

01/21/2017 10:34 PM

I wonder if there is a term like positive, negative or active grounding. It seems like there is. What could it be like.

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#11
In reply to #10

Re: Generator Neutral Grounding

01/22/2017 12:54 AM

For a person who doesn't know anything about anything whatsoever, you are certainly on the right garbage thread.

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#12
In reply to #11

Re: Generator Neutral Grounding

01/22/2017 9:24 AM

hmm,...the lightning is yours so as the twisters. Lots of thread are from power generation related these days, I will not wonder if someone gets electrocuted sooner or later.

This is somewhat like active grounding perhaps. Only the brave will try this one holding with a GI or copper pipe on a wet pants.

Do not try this at home

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#16
In reply to #10

Re: Generator Neutral Grounding

01/23/2017 2:08 PM

You get negative grounded batteries, positive grounded batteries. You also get DC supplies with a mid-point common, made with "active" amplifiers - so I guess all your proposals exist.

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#17
In reply to #10

Re: Generator Neutral Grounding

01/23/2017 10:59 PM

"... active grounding"

You mean 'virtual' grounds, like those often seen in op-amp circuits?

#1

-----

#2. Another type of circuit using a single battery to produce a 'dual-rail' power supply having a virtual ground.

-----

#3. Another dual supply, using a pair of 3-terminal voltage regulators.

Here the ground can be virtual or real, depending. This could work for instance as a dual supply providing a) +5V and +10V (real gnd), b) +5V and -5V (virt gnd), or c) -5V and -10V (virt gnd), depending which line you treat as the ground reference. Shown is case b):

But we're getting considerably off-topic here, no?

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#18
In reply to #17

Re: Generator Neutral Grounding

01/24/2017 6:19 AM

I was thinking of yr #2, which I have seen used in Bell & Howell vibration amplifier.

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#13

Re: Generator Neutral Grounding

01/22/2017 2:33 PM

any idea what will be the secondary loading resistor value and the grounding transformer impedence referred to any side.

Yes, but I am not telling you.

This is getting out of hand. You and your boss are acting in a vey unethical and dangerous manner.

You are clearly out of your depth so hire a professional consultancy firm for help. CR4 is not a substitute, nor should it be. If we continue to help and YOU get someone killed that's partly on us.

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#14
In reply to #13

Re: Generator Neutral Grounding

01/23/2017 5:11 AM

No it isn't. This is an anonymous forum. Especially with an undefined <...us...>.

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#15
In reply to #14

Re: Generator Neutral Grounding

01/23/2017 1:49 PM

Well yes it is because we would know. It's one of those ethical dilemmas, would you feel responsible if you helped someone do something that resulted in the death of another?

We wouldn't be having this conversation would we if this was a medical forum and a clearly unqualified doctor was asking us how to operate on a patient? Why should it be ethically any different for us Engineers on an Engineering forum?

A bad doctor can kill a patient or two, a bad Engineer could potentially kill many more.

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#19
In reply to #15

Re: Generator Neutral Grounding

01/24/2017 8:09 AM

Simply, because there is no such thing on this forum as <...we...>.

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#20
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Re: Generator Neutral Grounding

01/24/2017 8:32 AM

CR4 is an anonymous, international Engineering forum, and not a corporate body or a learned society. Contributions here are anonymous, voluntary, free of both charge and of payment, and based upon natural goodwill to others needing advice while carrying out Engineering activity anywhere on the planet. As an entity it has disclaimers in place that encourage the reader to carry out due diligence before acting on any advice contained herein. Such disclaimers discount liability, and the lack of real identity of its contributors make liability null. For example, were one to look for "PWSlack" in telephone directories, 192 People Finder, the Electoral Records or any other source of information for that matter, then one wouldn't be able to identify or locate anyone either to sue or to prosecute. And that is a good thing, for it encourages freedom of expression.

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#24
In reply to #20

Re: Generator Neutral Grounding

01/24/2017 2:22 PM

I am not questioning the legal, common sense, or free-advice-from-strangers aspects; it's about ethical responsibility from those that post answers.

Some people who ask questions on CR4 should not be given the answers, for their safety and others, especially if you are convinced they will likely use this information in an unethical way (such as to perform a job they are not qualified to do or repeatedly using CR4 as a crutch rather than putting effort into learning how to do it themselves).

Obviously this is a very grey area subject to personal interpretation of the limited provided information on CR4 and personal opinion.

Those that have never taken a course in professional ethics may only have a vague idea of what I am talking about. I and others will offer answers or express our opinions but others are free to also.

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#21

Re: Generator Neutral Grounding

01/24/2017 1:16 PM

First of all, I don't think someone takes us seriously since no one is actually interested on our answers. From the usually non significant data we get, we have to build a virtual story and answers very far from reality. So, in my humble opinion, we have to thank to Mr. Coolyaar for his inquiry and not blame him.

At the beginning of my carrier as an Electrical Engineer specialized in design and engineering of electrical machines-including transformers-the first open post I found was as designer of power supply station for water supply pumps.

The head of designer group asked me "to design a motor" for a pump. I asked him in turn, "it cannot be a standard one?" The answer was no, it is not listed [in tabulated??]. So I calculated the required HP and started the great my first job. After a few days, I returned to the head of group with ten pages of three alternatives of motor design including technology and list of materials. "What is this?" the manager cried, terrified, "I ask you to fit a motor to this pump only." "Sorry boss," I said, "in my world the sentence has to be 'choose a motor for this pump, not to design it. That's what I did in the first half an hour.'"

What I wanted to say is, "one could be a good engineer, but in a new job. What he needs is a simple engineering tip."

I am sure Mr. Coolyaar does not intend to build such a resistance nor to install it. Am I right?

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#22
In reply to #21

Re: Generator Neutral Grounding

01/24/2017 1:20 PM

Moral [to boss]: "Be careful what you ask for - you may actually get it."

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#23
In reply to #22

Re: Generator Neutral Grounding

01/24/2017 1:55 PM

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#34
In reply to #22

Re: Generator Neutral Grounding

01/25/2017 9:27 AM

haha.that was funny.

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#25
In reply to #21

Re: Generator Neutral Grounding

01/24/2017 2:27 PM

This is common here.

Many posters come here because they "have to design" a "thing" when in reality they just need to be pointed to a data sheet or catalog.

Haris, I believe, just wants someone to do his work for him.

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#26
In reply to #21

Re: Generator Neutral Grounding

01/24/2017 2:31 PM

Have a look at his question thread and post history, it raises a lot of red flags for me as someone who works in the power industry.

Repeated questions on HV MW scale system design and safety protection systems is quite a different kettle of fish to asking how to size a motor to a pump.

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#27
In reply to #26

Re: Generator Neutral Grounding

01/24/2017 2:41 PM

Cheating their way through school is a huge and age-old problem in India and Pakistan, in part because of huge social pressures to do so, and so it comes as no surprise that graduates eventually find their way into jobs where their lack of knowledge has potential to do great harm. Not only cheat their way through school, but continue this trend on-the-job to cover their arse. It's only a matter of time where thousands are killed as a result. I'm not saying this is the case here necessarily, but neither would I be surprised given the OP's other posts.

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#28
In reply to #27

Re: Generator Neutral Grounding

01/24/2017 2:55 PM

I (and others here I am sure) are aware of these problems and a number of the threads on CR4 could be argued to appear to be just that.

We don't normally state this in our posts but rather stick with what information we have as it can cloud discussions if we jump to conclusions, especially if we are not sure if this is actually the issue. May times we don't know where the poster is from, and what has appeared at first glance to be the case has turned out to be a simple misunderstanding due to language barriers or lack of communication issues.

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#29
In reply to #28

Re: Generator Neutral Grounding

01/24/2017 3:06 PM

Yes, but this particular OP is from Lahore, Pakistan where he supposedly graduated with a degree in Electrical Engineering. For someone with a degree in electrical engineering to be here asking this question and similarly uninformed questions on his other posts (about 3-phase load balancing, for example, posted anonymously), and what we have here is clearly not a language issue, but one of an 'education' possibly obtained by questionable means. For someone with an E.E. degree, he seems suspiciously unfamiliar with basic electrical principles. I'm just calling it as I see it.

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#30
In reply to #29

Re: Generator Neutral Grounding

01/24/2017 3:34 PM

I missed that bit of information (I can only work with what I have got), which post did this relevant bit of information come up in?

Not that it matters that much, I assumed he HAD to have an Engineering Degree or similar based on the serious high voltage and high power real world project questions he was asking for design answers on.

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#31
In reply to #30

Re: Generator Neutral Grounding

01/24/2017 3:42 PM
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#33
In reply to #31

Re: Generator Neutral Grounding

01/25/2017 12:25 AM

“Currently working as a Power systems Engineer in Schneider Electric Canada Inc.”

If this the same person I don’t know if I can agree with you.

Schneider Electric it has to be a good recommendation.

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#32
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Re: Generator Neutral Grounding

01/24/2017 5:14 PM

I have two very large issues with Haris, competence and conscience.

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#35
In reply to #29

Re: Generator Neutral Grounding

01/25/2017 9:34 AM

For your clarity, i never asked any question anonymously. i asked about things of which i was not 100% sure. i just needed to get confirmation from experts about what i learn. text books cannot give that confirmation because field problems are much different that what we studied in text books. Just give reference from one text book where they contain information about sizing of generator neutral grounding transformer and loading resistor and i will accept that i am incompetent else you will have to apologize.

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#36
In reply to #35

Re: Generator Neutral Grounding

01/25/2017 10:01 AM

I also believe that you are incompetent, and lazy.

The questions you ask indicate that you HAVE MUCH to learn and just don't want to put forth any effort!

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#37
In reply to #35

Re: Generator Neutral Grounding

01/27/2017 6:00 AM

<...will have to apologize...>

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#38

Re: Generator Neutral Grounding

01/27/2017 10:15 AM

You may consult Post Glover "the resistor specialist"

http://www.postglover.com/neutral-grounding-transformer/

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