OTI Recommendation

8/22/2019 OTI Recommendation

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Yunhyeong Kim : Haijun Liu [[email protected]] : 2012 8 27 11:32 : 'Yunhyeong Kim': ''; ''; ''; ''; ''; '': RE: [ETAP] Request teleconference for analyzing calculation result.

DearKim:

Aslongasyoumakesureapersonstandardsaroundtheequipmentdoesnotexposetomorethantolerabletouch

voltagethedesignwillbeok.

Sincerely,

Haijun Liu, PhD, PEPrincipal Electrical Engineer

OPERATION TECHNOLOGY, INC.

17 Goodyear, Suite 100

Irvine, CA 92618-1812

(949)4620100main

(949)4620200fax

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===========================================This e-mail message is intended only for the use of the individual or entity to which it is addressed and may contain information

that is privileged, confidential and exempt from disclosure under applicable law. If you are not the intended recipient of thismessage, you are hereby notified that any use, review, retransmission, dissemination, distribution, reproduction or any actiontaken in reliance upon this message is prohibited. If you received this message in error, please contact the sender. Any viewsexpressed in this message are those of the individual sender and may not necessarily reflect the views of the company.===========================================

From: Yunhyeong Kim [mailto:[email protected]]Sent: Monday, August 27, 2012 7:51 AMTo: Haijun LiuCc: ''; ''; ''; ''; ''; ''

Subject: [ETAP] Request teleconference for analyzing calculation result.

Dear Mr. Liu,

We calculated touch voltage include the electrical equipment as per your recommendation.

But result disposition is different with your calculation.


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Modeling file also attached for your checking.

In my opinion, this area is safe. Because area where electrical equipment is installed is safe, and area where the

touch voltage is high is a region where a structure will not be dissipating the current into ground.

Concerning the result of earthing calculation, we would like to have a teleconference meeting tomorrow at the

time as below.

Agenda : 1. Analyzing calculation result and confirming safety.

2. Reason of high touch voltage at the area between earth grid and electrical equipment.

3. Discussing technical solution if our design is un-safe.


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Time : 2012-08-28 08:00 a.m. (pacific time)

2012-08-28 07:00 p.m. (Abu-Dhabi)

Please confirm your availability for the same.

Thanks and regards

Yunhyeong Kim (Electrical Engineer)Electrical & Control System Engineering Dept.2 SAMSUNG ENGINEERING Co., Ltd.Office: +971-2-895-6119 Mobile : +971-50-773-9736E-mail : [email protected]

Confidentiality Notice: This e-mail is intended for the addressee named in the above. The information contained in this e-mail is

confidential and privileged. If you are not the intended recipient, you are hereby notified that any dissemination, distribution or copying of

this communication is strictly prohibited. If you have received this e-mail in error, please notify the sender immediately and destroy this e-

mail message. Thank you.

From: Haijun Liu [mailto:[email protected]]Sent: Saturday, August 25, 2012 4:46 AMTo: 'Yunhyeong Kim'Cc: ''; ''; ''; ''; ''; ''

Subject: RE: [ETAP] Question about boundary extension limit for earthing calculation

DearMr.Kim:

Youshouldaddsomebareconductors(suchasasquire)torepresenttheequipment.


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Sincerely,




Irvine, CA 92618-1812

(949)4620100main

(949)4620200fax



===========================================This e-mail message is intended only for the use of the individual or entity to which it is addressed and may contain informationthat is privileged, confidential and exempt from disclosure under applicable law. If you are not the intended recipient of thismessage, you are hereby notified that any use, review, retransmission, dissemination, distribution, reproduction or any actiontaken in reliance upon this message is prohibited. If you received this message in error, please contact the sender. Any viewsexpressed in this message are those of the individual sender and may not necessarily reflect the views of the company.===========================================

From: Yunhyeong Kim [mailto:[email protected]]Sent: Thursday, August 23, 2012 10:02 PMTo: Haijun LiuCc: ''; ''; ''; ''; ''; ''



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Dear Mr. Liu,

Thanks for your response.

I tried to calculate as per your suggestion below.

But ETAP still does not indicate the touch & step voltage at the area of installed PVC wire and additional rod.

Step & touch voltage is less than tolerable voltage. And step & touch voltage has been lower since adding

conductor and rod.

Is it possible to understand that electrical equipment which is connected by PVC insulated wire is safe from

touch voltage?

Additional conductor

and rod

Additional conductor and

rod is not indicated


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I attached the modeling file for reference.

Thank you very much and best regards,






From: Haijun Liu [mailto:[email protected]]Sent: Thursday, August 23, 2012 9:22 PMTo: 'Yunhyeong Kim'

Cc: ''; ''; ''; ''; ''; ''Subject: RE: [ETAP] Question about boundary extension limit for earthing calculation

DearMr.Kim:

Sincetheequipmentisconnectedtothegrid,itcouldexposetotheGPR.Iftheequipmentisnotinsulatedandcould

beexposedtohumantouching,thetouchvoltageshouldbeconsidered.Onesuggestionistoaddconductorsand

rodstorepresenttheequipment.Inthisway,ETAPwillincludetheequipmentinthecalculation.

Anotherthoughttomeisnottheconnecttheequipmenttothegrid.Usuallyoutdoorlightingpolesshouldbe

insultedanddonotneedtobeconnectedtoagroundgrid.

Sincerely,



17 Goodyear, Suite 100Irvine, CA 92618-1812

(949)4620100main

(949)4620200fax

Lib Downloads http://www.etap.com/support/downloads.htmFAQ & Tutorials http://etap.com/support/faqs.htmWorkshops http://www.etap.com/training/events.htmContact us [email protected]

===========================================

This e-mail message is intended only for the use of the individual or entity to which it is addressed and may contain informationthat is privileged, confidential and exempt from disclosure under applicable law. If you are not the intended recipient of this

message, you are hereby notified that any use, review, retransmission, dissemination, distribution, reproduction or any action


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taken in reliance upon this message is prohibited. If you received this message in error, please contact the sender. Any viewsexpressed in this message are those of the individual sender and may not necessarily reflect the views of the company.===========================================

From: Yunhyeong Kim [mailto:[email protected]]Sent: Thursday, August 23, 2012 7:07 AMTo: Haijun LiuCc: ''; ''; ''; ''; ''; ''


Dear Mr. Liu,

Thanks for your valuable response.

We are making progress in trying to convince our client but one doubt remains.

Please see the sketch below, it is almost identical with the one that we had sent to you earlier; in this

case we consider electrical metallic equipment next to a person. In the case below, the equipment is

connected by PVC insulated wire to the earthing grid only.

Do we have to verify the touch voltage for this equipment or metallic structure?

If that is the case how to verify safety from touch voltage by using ETAP? PVC insulated wire is

just considered as a conductor, but is not considered source of current dissipation by ETAP.Boundary extended length may not be solution for verifying touch potential to the equipment as shown

below.

Thank you very much & best regards,






From: Haijun Liu [mailto:[email protected]]Sent: Sunday, August 19, 2012 8:40 PMTo: 'Yunhyeong Kim'


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Cc: ''; ''; ''; ''; ''; ''


DearMr.Kim:

Pleaserefertotheattachedfortouchvoltagedefinition.

ForaPVCinsulatedwire,ETAPtreatsitasaelectricconductorbutitdoesnotdissipatecurrentintoground.

Sincerely,



17 Goodyear, Suite 100Irvine, CA 92618-1812

(949)4620100main

(949)4620200fax


===========================================

This e-mail message is intended only for the use of the individual or entity to which it is addressed and may contain informationthat is privileged, confidential and exempt from disclosure under applicable law. If you are not the intended recipient of thismessage, you are hereby notified that any use, review, retransmission, dissemination, distribution, reproduction or any actiontaken in reliance upon this message is prohibited. If you received this message in error, please contact the sender. Any views

expressed in this message are those of the individual sender and may not necessarily reflect the views of the company.===========================================

From: Yunhyeong Kim [mailto:[email protected]]Sent: Friday, August 17, 2012 2:47 AMTo: Haijun LiuCc: ''; ''; ''; ''; ''; ''


Dear Mr. Liu,


Could you provide the screen capture file about limitation of touch potential?

We dont have IEEE80 due to the site condition.

In addition, is it possible to understand that touch potential does not need to be considered at the area of

grounded structure which is connected by PVC insulated wire.

Because ETAP does not consider PVC insulated wire when calculate step & touch potential.


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From: Haijun Liu [mailto:[email protected]]Sent: Friday, August 17, 2012 3:13 AMTo: 'Yunhyeong Kim'Cc: ''; ''; ''; ''; ''; ''


DearMr.Kim:

PleaserefertoIEEEStd80fordefinitionandlimitationoftouchpotential.

Thereisnoglobaldefinitionforsafety.Itdependsonengineerjudgmentandorganizationpractice.Formy

understandingaslongasahumandoesnotexposetothelimitedtouchpotentialitshouldbesafe.

Sincerely,

Haijun Liu, PhD, PE

Principal Electrical Engineer



Irvine, CA 92618-1812

(949)4620100main

(949)4620200fax

Lib Downloads http://www.etap.com/support/downloads.htmFAQ & Tutorials http://etap.com/support/faqs.htm

Workshops http://www.etap.com/training/events.htmContact us [email protected]

===========================================


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This e-mail message is intended only for the use of the individual or entity to which it is addressed and may contain informationthat is privileged, confidential and exempt from disclosure under applicable law. If you are not the intended recipient of thismessage, you are hereby notified that any use, review, retransmission, dissemination, distribution, reproduction or any actiontaken in reliance upon this message is prohibited. If you received this message in error, please contact the sender. Any viewsexpressed in this message are those of the individual sender and may not necessarily reflect the views of the company.===========================================

From: Yunhyeong Kim [mailto:[email protected]]Sent: Thursday, August 16, 2012 4:05 AMTo: Haijun LiuCc: ''; ''; ''; ''; ''; ''


Dear Mr. Liu,

Thanks for your valuable response.

Could you inform us why the touch potential does not need to be considered?

Please provide technical reasons for answer number 2.

Once getting approval from our client, we shall provide technical reasons to them.

Best regards,




this communication is strictly prohibited. If you have received this e-mail in error, please notify the sender immediately and destroy this e-mail message. Thank you.

From: Haijun Liu [mailto:[email protected]]Sent: Wednesday, August 15, 2012 10:54 PMTo: 'Yunhyeong Kim'Cc: ''; ''; ''; ''; ''; ''


DearMr.Kim:

Regardingyour

questions:

1.Yes,itreferstocase1only.

2.Yes,thisshouldbeok.Iassumethatthe70sqmmbarecopperconductorsareburiedunderground.Pleasemake

suresteppotentialaroundthe70sqmmbarecopperconductorsaregood.

Sincerely,



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Irvine, CA 92618-1812

(949)4620100main

(949)4620200fax




that is privileged, confidential and exempt from disclosure under applicable law. If you are not the intended recipient of thismessage, you are hereby notified that any use, review, retransmission, dissemination, distribution, reproduction or any actiontaken in reliance upon this message is prohibited. If you received this message in error, please contact the sender. Any viewsexpressed in this message are those of the individual sender and may not necessarily reflect the views of the company.===========================================

From: Yunhyeong Kim [mailto:[email protected]]Sent: Wednesday, August 15, 2012 7:49 AMTo: Haijun LiuCc: ''; ''; ''; ''; ''; ''


Dear Mr. Liu,

Thanks for your cooperations.

We intend to finalize the selection of boundary extension. So please answer to below 2 questions.

1. Could you please inform us what is an accurate meaning for "boundary extension for touch potential" ?

We have represented 2 cases below. Is it matching to case 1? case 2? or both?

Our understanding is that using boudary extension refers to case 1 only.

2. We sketched conceptual earthing system as follows;We shall calculate step & touch potential for in-between earthing grid areas as per our client request.


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But we divided the entire calculation into 17 calculations for performing calculation of 2 earthing grids only.

Because we cannot calculate entirely plant because huge data processing is required.

If we use 0m boundary extend, ETAP calculates the area limited as blue line below.

Is it possible to verify that all in-between grids areas are safe from touch potential with earthing calculation

using 0m boundary?

We would appreciate your support in understanding precisely this matter, in order to proceed forward.

Thanks in advance

Best regards






From: Haijun Liu [mailto:[email protected]]Sent: Thursday, July 26, 2012 9:44 PMTo: 'Yunhyeong Kim'Cc: ''; ;


DearMr.Kim:


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ThebestreferenceistheIEEEStd80.

Isthepiperackconnectedtothegroundgrid?Ifitis,thiscouldbeaproblembecauseitwillhavethesameGPRas

thegrid.Otherwisethereisnodifferenceforapersonstandsonthesurfacecoveringthepiperack.

Sincerely,




Irvine, CA 92618-1812

(949)462

0100

main

(949)4620200fax



that is privileged, confidential and exempt from disclosure under applicable law. If you are not the intended recipient of thismessage, you are hereby notified that any use, review, retransmission, dissemination, distribution, reproduction or any action


From: Yunhyeong Kim [mailto:[email protected]]Sent: Wednesday, July 25, 2012 5:52 AMTo: Haijun LiuCc: ''; ;


Dear Mr. Liu,

Thanks for your cooperation.

Could you give me some technical basis of your response? (e.g. Some equations, Reference code and

standard, or theoretical explanations)

Our client still want to know why piperack is not need to be considered. If attached earthing calculation is

correct, most dangerous area is outside of earthing grid where the piperack or another grounded structures are

installed. Because touch voltage is the potential difference between the GPR and surface potential at the point

where a person is standing while at the same time having a hand in contact with a grounded structure. They

think grounded structure means all structure(e.g. pipe rack, tank, vessel) which is installed on the ground.

All earthing grids in the site are connected to make one large earthing grid. And all grounded structure

connected to earthing system. This is not only for the substations.


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Im sorry for difficult question.

Thanks & Best regards,






From: Haijun Liu [mailto:[email protected]]Sent: Wednesday, July 18, 2012 9:47 PMTo: 'Yunhyeong Kim'

Cc: ''; 'Harris Melvin (External)'Subject: RE: [ETAP] Question about boundary extension limit for earthing calculation

DearKim:

Yes,youmayhave30masboundaryextensionforbothstepandtouchvoltagecalculation.Forthehighertouch

potentialissue,justmakesureahumanstandatthepointswon'tbeabletotouchanequipmentinthesubstation

oranythingconnectedtothegrid.Itisnotnecessarilytohaveaphysicalprotectivedevicesuchasafence.Cana

personstandtheretotouchanequipmentinthesubstationwithhis/herarm(orwithastick)?

Sincerely,




Irvine, CA 92618-1812

(949)4620100main

(949)4620200fax


===========================================This e-mail message is intended only for the use of the individual or entity to which it is addressed and may contain informationthat is privileged, confidential and exempt from disclosure under applicable law. If you are not the intended recipient of this

message, you are hereby notified that any use, review, retransmission, dissemination, distribution, reproduction or any actiontaken in reliance upon this message is prohibited. If you received this message in error, please contact the sender. Any views

expressed in this message are those of the individual sender and may not necessarily reflect the views of the company.===========================================


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From: Yunhyeong Kim [mailto:[email protected]]Sent: Wednesday, July 18, 2012 4:55 AMTo: Haijun LiuCc: ''; 'Harris Melvin (External)'


Dear Mr. Liu,


But please response after considering following conditions;

- Our client want to verify safety of all plant area not only substations. Because IEEE80 explain that touch

potential is the potential difference between the ground potential rise (GPR) and the surface potential at

the point where a person is standing while at the same time having a hand in contact with a grounded

structure. But we cannot physically protect for all structure in the plant (e.g. pipe rack).

- We cannot calculate entirely plant because huge data processing is required. So we divided the entire

calculation into 17 calculations for performing calculation of 2 earthing grid only.

- I inputted 30m boundary extension limit as step potential calculation and 0m boundary extension limit as

touch potential. But our client doesnt want different input data between touch potential and step

potential. So I need verify that this input data is correct.

- I attached example calculation which is using 30m extention boundary limit for reference. As per this

result most dangerous area is 30m far from substation earthing grid perimeter. But most dangerous area

shall be inside of substation earthing grid. Because any electrical equipment shall not be installed outside

of substation rectangular earthing grid. Only small lighting panel shall be installed in outside of earthing

grid.

So please advise the specific input data of boundary extension limit without considering physical protection.

And if some condition is wrong, please do not hesitate to advise it.

Best regards,






From: Haijun Liu [mailto:[email protected]]Sent: Wednesday, July 18, 2012 4:58 AMTo: '???'; 'Yunhyeong Kim'Cc: ''


DearMr.Kim:


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Boundaryextensionisnotnecessary,ifoutsideoftherectangularareaisprotectedphysicallyasstatedinmy

previousemail.

Sincerely,




Irvine, CA 92618-1812

(949)4620100main

(949)4620200fax


===========================================This e-mail message is intended only for the use of the individual or entity to which it is addressed and may contain informationthat is privileged, confidential and exempt from disclosure under applicable law. If you are not the intended recipient of thismessage, you are hereby notified that any use, review, retransmission, dissemination, distribution, reproduction or any action


From: [mailto:[email protected]]

Sent: Tuesday, July 17, 2012 5:23 PMTo:; Haijun Liu; 'Yunhyeong Kim'

Cc: ''


Dear Mr. Liu,

Your valuable response is highly required.

If I incorrect, please recommend the correct input data of boundary extension limit for touch potential.

Best regards,

kimyh187.


17/24

17

-----Original Message-----

From: ""To: "Haijun Liu"; "'Yunhyeong Kim'";Cc: "''";Sent: 2012-07-18 () 02:48:12Subject: RE: [ETAP] Question about boundary extension limit for earthing calculationDear Mr. Liu,

Yes. You right, Pipe racks shall be installed some in-between grid areas.

But, my question is that boundary extention limit is required or not in case of touch potential calculation.

As I know GPR is locally generated, but ETAP considered GPR is generated entirely in the calculated area.

Any electrical equipment will be installed outside the grid area or in-between grid area.

Hence in my opinion, 0m boundary extention limit shall be considered for touch potential calculation.

Please advise it.

Best regards,

kimyh187.

-----Original Message-----From: "Haijun Liu"To: "'Yunhyeong Kim'";Cc: "''"; "[email protected]";Sent: 2012-07-18 () 02:06:14Subject: RE: [ETAP] Question about boundary extension limit for earthing calculationDearMr.Kim:

Yes,youneedmakesurethattouchpotentialsintheareasthatarenotphysicallyprotectedareinthetolerable

limit.Youmaylookattheplotsorreports.

Sincerely,

Haijun Liu, PhD, PE



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Irvine, CA 92618-1812

(949)4620100main

(949)4620200fax


FAQ & Tutorials http://etap.com/support/faqs.htm

Workshops http://www.etap.com/training/events.htm

Contact us [email protected]

===========================================

This e-mail message is intended only for the use of the individual or entity to which it is addressed and may contain information

that is privileged, confidential and exempt from disclosure under applicable law. If you are not the intended recipient of thismessage, you are hereby notified that any use, review, retransmission, dissemination, distribution, reproduction or any action

taken in reliance upon this message is prohibited. If you received this message in error, please contact the sender. Any viewsexpressed in this message are those of the individual sender and may not necessarily reflect the views of the company.

===========================================

From: Yunhyeong Kim [mailto:[email protected]]Sent: Tuesday, July 17, 2012 9:56 AMTo: Haijun LiuCc: ''; [email protected]

Subject: FW: [ETAP] Question about boundary extension limit for earthing calculation

Dear Mr. Liu,

My response can be answer your 2 emails.

Please reply after considering our situations.

And please include my private email address.


19/24

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Many thanks for your prompt response.

Best regards,






From: Yunhyeong Kim [mailto:[email protected]]Sent: Tuesday, July 17, 2012 8:52 PMTo: 'Haijun Liu'Cc: ''


Dear Mr. Liu,

Each earthing grid covers the hole substation and transformers. Moreover substation is building type andoutdoor transformers are protected by fence.

But two interconnecting wire shall be installed in-between all the substations or process units earthing grid.

Please refer to earthing block diagram.

So we need to verify that this interconnecting area is safe. That area is not inside the substations. Hence, we

cannot install the fence for this area.

Please refer to attached modeling file.

So I want to get your confirmation boundary extention limit shall not be used to calculate touch potential fornot only inside the substation but also normal field area.

Best regards,





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From: Haijun Liu [mailto:[email protected]]Sent: Tuesday, July 17, 2012 8:20 PMTo: 'Yunhyeong Kim'

Cc: ''Subject: RE: [ETAP] Question about boundary extension limit for earthing calculation

DearYunhyeongKim:

Yes,youonlyneedtomakesure:

1.The

touch

and

step

potentials

inside

the

grid

area

both

meet

the

tolerable

potential

requirements.

2.Thesteppotentialoutsidethegridareameetsthetolerablepotentialrequirement.

3.Thehighertouchpotentialoutsidethegridshouldbeprotectedbyaphysicalmethodsuchasafence.Notethatif

thereisequipment outsidethegridarea,thegridneedstobeextended.

Doesyourgridcoverthewholesubstation?Isthereafencesurroundthesubstation?

Sincerely,

Haijun Liu, PhD, PE




Irvine, CA 92618-1812

(949)4620100main

(949)4620200fax


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FAQ & Tutorials http://etap.com/support/faqs.htm

Workshops http://www.etap.com/training/events.htm

Contact us [email protected]

===========================================

This e-mail message is intended only for the use of the individual or entity to which it is addressed and may contain informationthat is privileged, confidential and exempt from disclosure under applicable law. If you are not the intended recipient of thismessage, you are hereby notified that any use, review, retransmission, dissemination, distribution, reproduction or any actiontaken in reliance upon this message is prohibited. If you received this message in error, please contact the sender. Any viewsexpressed in this message are those of the individual sender and may not necessarily reflect the views of the company.

===========================================

From: Yunhyeong Kim [mailto:[email protected]]

Sent: Tuesday, July 17, 2012 8:55 AMTo: Haijun LiuCc: ''

Subject: [ETAP] Question about boundary extension limit for earthing calculation

&

wx


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1(16MB) 30 / 100earthcalc_modelinzip16MB PC|N

: 2012/07/18 ~ 2012/08/17

*

W

+

&

E-mail :

+

, , .

.


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Thanks f or cont act i ng ETAP t echni cal suppor t .

I n ETAP FEM, Boundar y Extensi on i s provi ded so t hat users can i nvest i gate t he st ep and

t ouch pot ent i al s out si de t he gr i d. I t i s al ways t r ue t hat t he hi ghest t ouch pot ent i al

i s around t he gr i d per i met er and t ouch pot ent i al wi l l be even hi gher out si de the gr i d.

Thi s i s because t he t ouch potent i al i s t he potent i al between a person' s f eet and ar ms

( GPR) when he/ she t ouches equi pment s i n t he subst at i on. The di f f er ence i s get t i ng

bi gger si nce t he act ual pot ent i al get t i ng l ower ( unt i l r each t o 0) when i t i s f ar away

f r om t he subst at i on.

The unacceptabl e t ouch potent i al outsi de t he gr i d usual l y i s not sol ved by enhanci ng

t he gr i d. I t shoul d be physi cal l y ( such as wi t h a f ence) pr ot ect ed f r om human exposi ng

t o thi s hi gh touch pot ent i al . Thi s means t hat a human won' t be abl e to touchequi pment s i n t he subst at i on when he/ she i s st andi ng out si de t he gr i d. Note t hat t he

st ep pot ent i al out si de of t he gr i d needs t o be i n t he r equi r ed l i mi t .

I f you need f ur t her assi st ance on t hi s i ssue pl ease f eel f r ee t o cont act me.

Hai j un Li u

ETAP Techni cal Suppor t

From: [mailto:[email protected]]

Sent: Tuesday, March 20, 2012 1:11 AM

To:[email protected]

Cc:

Subject: ETAP. ()


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