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Noorirm
Active Contributor

Join Date: Jun 2008
Posts: 24

11KV over head line

07/02/2010 5:03 AM

Dear friends.

I have a problem with 11KV over head feeder . But I would like to explain for u in brief words the strange operation procedure here in IRAQ.

We face a special problem since 2003 that is coming from

1- Old electrical system that is in power plant , HT over head transmission lines with its distribution station ,and 11KV over head distribution lines.

2- The unexpected increasing in the electric consumption.

So according to this condition the 11KV feeder will stay ( switched on ) for 2 hours and (switched off) for 4 hours or more . During the shutdown duration the area for each distribution transformer will get the electrical power by another system which is ( local generating set ) 650KVA and more.

Now let me explain u the problem in this feeder that is feeder tripped when its switched on and some time the aluminum over head lines broken and full down.

This feeder has 12 distribution transformers two of them are 400KVA and the other are 250KVA and all of them working without LT CB.

Now I hope u understand this unbelievable operating system and u can help me to solve this problem.

Best regard.

Note.

The tripped signal is cubical fault( over current )
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PWSlack
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#1

Re: 11KV over head line

07/02/2010 6:49 AM

Hire a specialist locally, who has the experience to deal with the particular problems that this installation faces.

  • If the specialist gets it right, fine.
  • If the specialist gets it wrong, sue for damages. If a CR4 poster gets it wrong, one cannot do this and it is back-to-square-one!
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Le_Noble
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#2
In reply to #1

Re: 11KV over head line

07/02/2010 7:28 AM

PwSlack .

This is in IRAQ, I guess you know what does this mean, no more specialists, all gone and escaped...I guess Noor is the last specialist staying in Iraq, Cheers to him..

Noor,

Your feeder is undersized for the load, you have a total of 3300KV, about 200 Amp in the feeder in normal run, at switch on time you have the energizing current of the transformers, with 12 transformers of this size switched on at the same time you can get easily 1600 Amp for seconds.

Does your protection devise is sized for this current?

What type of switch you use? what is the tripping device? may be you have to adjust the setting of trip unit?

In which Mohafazat in Iraq you are working? is it for a city power grid or to a coalition military site ?

I have a crew working now in North of Iraq, if you are in the around, email me in private I will let them contact you to exchange some ideas,

something else you can do, if you can print the setting of the trip unit and post it here or email it to me, we can check if the setting is correct for this load...

greetings, Nabil

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Noorirm
Active Contributor

Join Date: Jun 2008
Posts: 24
#10
In reply to #2

Re: 11KV over head line

07/08/2010 5:26 PM

Dear Noble.

Thank u for your attention ,Actually I am in the Karballa muhafsa that is 90Km south west of Baghdad , I send u my private e mail and I will visit your group as soon as I can.

Here the data for 11KV C/ B used with this feeder.

Type Scheider

Ur 12KV

Up 75KV

Ud 28KV/50HZ/1mn

Fr 50HZ

Ir 630A

Seq 0.03s-co.15s-co

Isc 31.5KA t=3s

Actually I check the feeder columns one by one by visual inspection and I didn't find any cause to tripped the feeder so I split the load and then switched the feeder on successfully.

Feeder tree is about 12KM.

BEST REGAED
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mountk2
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#3

Re: 11KV over head line

07/02/2010 10:04 AM

For the O/C relay to be there you should have three settings:

One is time delayed, take into account the starting inrush time of the transformer(s) and calliberate time delay of the relay to avoid tripping.

Second is instantanious O/C, take into account the minimum system fault level.

Third is short circuit protection instantaneous element here the setting will be greater than instantaneous O/C as per the short circuit level.

Modern numerical O/C relays have all the three elements built in one unit.

If more than one relay is there you have to carry out protection coordination.

I can understand your situation if you are in Iraq, so if you have some very old relay setup try to work out by hit and trial.

One sensible option would be to split the load on two feeders with individual HT switchgear and protection.

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Noorirm
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Join Date: Jun 2008
Posts: 24
#11
In reply to #3

Re: 11KV over head line

07/08/2010 5:43 PM

Dear mountk2

Thanks so much for your response to my thread.

I will write u all the necessary data for the protection relays that is using with this C/B as soon as I meet my friend who is responsible about the substation maintenance. Unfortunately I didn't meet him this week because I should finish a lot of work in this week.

BEST REGARD.
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Anonymous Poster
#4

Re: 11KV over head line

07/02/2010 2:10 PM

It is just off topic but I like to use this forum as I am observing a lot of People from middle east are using this forum and making life miserable for others if they have guts please respect knowledge .

"Once there was a lion who was in his country zoo having a good meal life .once there was a oil middle east sheikh visited the zoo .The organizers proudly show the lion to oil middle east sheikh . The oil middle east sheikh liked the lion very much and the other lions said to lion you are lucky they are taking you to best place it will be like heaven .The lion felt proud and finally the oil middle east sheikh gave a large amount of money and transfer it to Middle east ZOO .1st day they give him bananas 2nd day he got bananas third day things difficult for him he was dying with hunger he shouted at the zoo guys "WHY ARE YOU GIVING ME BANANAS DONT YOU KNOW WHAT A LION EAT " the attendant replied --please note it – "YOU ARE ON A MONKEY VISA SO SOLONG AS YOUR VISA IS YOU ARE A MONKEY " "---Moral of story please check your visa before travel to middle east may be they give you a monkey visa .

Please please please they are making life a hell for expatraites and if you are thinking to support them

think twice

Ferth
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Le_Noble
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#6
In reply to #4

Re: 11KV over head line

07/03/2010 7:17 AM

I forwarded your post to administrator, this is a pure racism,

you are not obliged to read and answer.

For who is making the life of others miserable, refer to your politicians debate you will know...

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Anonymous Poster
#7
In reply to #6

Re: 11KV over head line

07/03/2010 2:19 PM

You said i am racist.

You must have proof when you said something please i requested my colleagues if you don't know ask any Indian Pakistani they may have friends there

In UK Canada US European countries In middle east Saudi , Qatar , Kuwait ,UAE etc etc
Every child born is supplied with education medical facilities regardless of ethnic origin colour or race People worked all there life on extended visas no medical from govt side no education for their children they remain a 3

rd degree citizen for their life every day they cursed

Free medical NHS in UK same in US Canada It is mention on hospital don't enter if you are an expatriate you will not be entertain even you died
Free education and skill oriented programs No education most of people of middle class give their children on their home country
Full research and engineering real ones Largest fake degrees are in middle east companies you can see they took every thing don't even have the sense of copy paste
Women and men are equal i don't support vulgarity but women can do what she desire Since 50 years still debate that women can drive a car or not what a crap
People share and help each other in knowledge Only the copy paste culture no inventions

Except in some field of electrical engineering Indians and Pakistanis are real good

Truth is base here no concept of forgery or any false vision Any one who is suspecting on these points is invited to spent some time he will add double in this
Nationality you can buy do business what ever you are in free society You can not get a 3nd degree nationality if you want to go to bathroom get permission letter from your sponsor
Dear i am not racist please think and let your people think if they can

stealing knowledge is not solution
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Le_Noble
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#8
In reply to #4

Re: 11KV over head line

07/03/2010 3:19 PM

No need for this comparaison table, WHY YOU ARE HERE AS LONG AS YOU HAVE ALL THE KNOWLEDGE AS YOU PRETEND??? KEEP THIS FORUM FOR IGNORANTS LIKE US....

it is very simple , if you dont like dont come here, no body force you to come to these countries...

This s your quote, what do you call this if not a racism? Tolerance may be!!!

Please please please they are making life a hell for expatraites and if you are thinking to support them think twice\

ANY WAY PLEASE SHOW YOUR CIVILISED FACE AND KEEP THIS FORUM FOR PROFESSIONAL USE, AT LEAST REGISTER TO THIS FORUM AND SHOW UP, DONT HIDE BEHIND "GUEST" LABEL.

IF YOU WANT TO SHOW YOUR HATE I CAN SUGGEST YOU OTHER FORUMS

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Noorirm
Active Contributor

Join Date: Jun 2008
Posts: 24
#9
In reply to #4

Re: 11KV over head line

07/08/2010 5:20 PM

Guest.

1- first this is not off topic, and I am in right position when I write in the thread that's un believable case and u will here more such condition if u stay in touch with me or if u decide to visit IRAQ then u will understand the hard conditions that facing IRAQ since 30 years ago.

2- I hope to here from Guest a good answer so that we can solve all the problem together via the RC4.

Regard.
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ikhanuk
Commentator

Join Date: Aug 2009
Posts: 91
#13
In reply to #4

Re: 11KV over head line

07/24/2010 6:09 AM

Dear All ,

Mr. Ferth It seems you are English .I respect every one that's what I learn from my education I graduated from UK .Mr Nabil I also respect your opinion. I am a muslim and try to be honest as I can .Ferth I have lived in the middle east region I don't like to mention the name of the country as it is the most honored country for Muslims .But let me share my personal experience when I was working there as electrical engineer .I cannot forget the behavior that completely destroyed me my family and we moved to UK. My 5 months old daughter sick and they didn't accept in emergency why "BECAUSE I AM PAKISTANI AND I AM NOT ARAB " . That night was one of the toughest but that change the whole idea and yes Mr. Nabil is absolutely correct if we don't like why we work there so I am no more there I don't want to be there .I have non muslim friends they are excellent in respect , manners .My wife is free to go drive education . what they show there are not like that its simply fake .Fake companies fake engineers no one likes to work big salaries and worst ********* .

If anyone hurts sorry for all those comments but you can understand that it all happened on me I didn't listen from someone .Please make sure when you put forward any case you are on right side .Please try to make this world a better place

Love you all

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Le_Noble
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#14
In reply to #13

Re: 11KV over head line

07/24/2010 2:06 PM

No body talked about muslims or non-muslims, if this of interest to you, I am from Lebanon and not muslim,

I was replying to Mr Freth, he asked the posters not to reply on midel-eastern questions, just because he had problems somewhere in Dubai, and he show an unacceptable level of hate to these countries and he sent a comparison table to confirm his hate.

My point was this is not the right place for his complaints, leave this forum for technical use, and if someone does not like us please don't come, and resolve your unemployment problems with your politicians, who are the ones making your life as a hell, not us,

Again please leave this forum for borderless engineering community

Regards to all

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ikhanuk
Commentator

Join Date: Aug 2009
Posts: 91
#15
In reply to #14

Re: 11KV over head line

07/25/2010 1:57 AM

Dear Nabil

I have no intention to differentiate between Muslims and Non Muslims as I have said I have some very good friends and they are Non Muslims and my personal experience in a very strict Muslim country with strict Muslim rules is not very good to be honest it is a family disaster .I must say one thing it is all against basic human rights.

When in a society the honourable people removed regardless of religion then the bad elements become in power that is what is exactly happening in Middle East region .Also the complete laws are crap.

So I personally agree with Mr. Ferth you are absolutely correct Nabil that we should use this forum for knowledge share, but please consider if an inexperience uneducated fake degree engineer use this forum and he has also power in management then what will happen I think that was Mr. Ferth indicating.

Thank you all for reading and comments

God Bless you

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wareagle
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#5

Re: 11KV over head line

07/02/2010 10:04 PM

Noorirm

1. What is the capacity of the generating plant?

2. Have you measured the actual current flow per phase on the feeder?

3. What size conductor is the feeder?

4. How long is the feeder?

5. Are these transformers for residential or industrial loads?

6. Does No LTCB mean no primary fuses? if so, Why not?
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Noorirm
Active Contributor

Join Date: Jun 2008
Posts: 24
#12
In reply to #5

Re: 11KV over head line

07/08/2010 6:18 PM

Dear wareagle.

First thank u for your attention.

1-The feeder is located in 132KV /33KV&11KV power transformer.

2-yes the current is 150A.

3-conductor size is 150mm2.

4-about 12KM .

5-Residantal and industerial loads

6-No 380V c/b are connected to the transformer.

best regard.
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Users who posted comments:

Anonymous Poster (2); ikhanuk (2); Le_Noble (4); mountk2 (1); Noorirm (4); PWSlack (1); wareagle (1)

Previous in Forum: Harmonics filter capacitive or inductive   Next in Forum: Amount of A/C's On A 125 KVA Generator

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