design & development of software for optimized design of grounding system

7/24/2019 DESIGN & DEVELOPMENT OF SOFTWARE FOR OPTIMIZED DESIGN OF GROUNDING SYSTEM

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DESIGN & DEVELOPMENTOF SOFTWARE FOR OPTIMIZED

DESIGN OFGROUNDING SYSTEM

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Dissertation Phase - 2Dissertation Phase - 2

Prepared by:Pranav JaniEn. No.: 12026073700064th Semester,M. E.(E. P. S.)

Guided y:Mr. An it !a""arAsst. Pro#.E$e%tri%a$ En&ineerin& 'e artment,

*+ - ,a$o$.


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!ro/n in& S stem: An *ntro /%tion*m ortan%e o# !ro/n in&*EEE Metho o$o& #or !ro/n in& S stemN/meri%a$ Ana$ sis o# !ro/n in& S stem

'eve$o ment o# So#t areSo#t are a$i ation

on%$/sion/t/re P$annin&

-e#eren%es

2

F!"# "$ Pre%e 'a'i"


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Gr"u di ( Sy%'e): A I 'r"du*'i"

On its way from generating station to the end consumer,electrical power passes through different kinds ofsubstations.Successful operation of complete power system dependsto a considerable extent on efficient and satisfactory

performance of substations.Hence substations in general can be considered as heart ofentire power system. In any safe and reliable substation a well designedgrounding plays vital role.This can be easily visuali ed from following points


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I)p"r'a *e "$ Gr"u di ( Sy%'e)

!rounding system provides a place for connecting systemneutral points, e"uipment body and support structures tothe earth.It also ensures safety of working personnel within thesubstation and enables earth fault detection and

protection.It provides path for discharging the earth currents fromneutrals of e"uipments, faults, surge arrestors, overheadshielding wires etc.

It keeps step and touch potential within tolerable limits.


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I)p"r'a *e "$ Gr"u di ( Sy%'e)

Hence properly designed and installed grounding systemensures #eliable performance of electrical substation Safety of persons working within or near substation

from the dangers of electric shock under faultconditions

!round potential rise $!%#& limited within theacceptable levels

'lectrical current dissipated into earth withoutexceeding operating limits of e"uipment


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a%i* S+"*, Si'ua'i" % -./

In the substation there are basically five type of differentshock conditions Touch (oltage Step (oltage )esh (oltage )etal to metal contact (oltage Transferred (oltage

Out of these five , first two conditions are of main interest

because of fre"uency of their occurrence*ollowing figures show Touch and Step voltage scenarioand their e"uivalent circuits.


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S'ep V"!'a(e S*e ari" & E0ui1a!e ' 2ir*ui' -./


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T"u*+ V"!'a(e S*e ari" & E0ui1a!e ' 2ir*ui' -./


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IEEE Me'+"d"!"(y $"r Gr"u di ( Sy%'e)De%i( -./

)ain thing to be taken care of while designing grounding

system is that actual mesh and step voltages should beless than the tolerable voltages.There are main two design goals to be achieved by anysubstation grounding system under normal as well as

fault condition.'esi&n &oa$s To assure that a person in the vicinity of grounded

facilities is not exposed to the danger of critical

electric shock. To provide means to dissipate electric currents into

the earth without exceeding any operating ande"uipment limits.


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IEEE Me'+"d"!"(y $"r Gr"u di ( Sy%'e)De%i( -./

)ain ob+ective while designing grounding system as per

I''' guide is thatactual step and touch voltages must not exceed the

maximum permissible step and touch voltagesdefined by following equations even in the worst

case. -Safety criteria given by I''' are as follows


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Sa$e'y *ri'eria (i1e by IEEE 34 5 6444 -./

s s stouch t

C E //0.1

&2.//111$21

+=

s s s step

t C E /23.1&0/111$31 +=

s

s stouch

t

C E /23.1

&2.//111$31 +=

*or 4ody weight of 21 kg

*or 4ody weight of 31 kg

s s s step

t C E //0.1&0/111$21 +=


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Sa$e'y *ri'eria (i1e by IEEE 34 5 6444 -./

5here,

6 Step %otential6 Touch %otential6 Surface )aterial #esistivity6 Surface 7ayer 8e9rating *actor 6 8uration of :urrent 'xposure in Second

step E touch E

s

sC

st


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Nu)eri*a! A a!y%i% "$ Gr"u di ( Sy%'e)-6/

*igure $a& shows the simple

!rounding System.

*igure $b& shows the smallsegments of the ground grid inwhich current is emanate fromthe segment.

*igure $c& shows the point sourceof the current and the voltage atthe surface of the segment


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Nu)eri*a! A a!y%i% "$ Gr"u di ( Sy%'e)-6/The voltage ( i of segment i at point ;,

5here,

6 coordinates of point ; located on

the surface of segment i6 coordinates of the center of

segment +6 total electric current emanating

from the surface of segment +

==

n

j

A A Ai

j j j jiii I z y x z y x f V /

&,,,,,,$

$=&$&$&?>$

@/

&,,,,,,$

2.1AAA

2.1AAA

+

+++++

=

ji ji ji

ji ji ji

j j jiii

z z y y x x z z y y x x

z y x z y x f

A A A

A A A

A A A

&,,$ iii A A A z y x

&,,$ j j j z y x

j I


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The voltage ($ x,y,z & at any point $ x,y,z & in the earth can be

computed by below e"uation,

=

=n

j

j j j j I z y x z y x f z y xV /

&,,,,,,$&,,$


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Nu)eri*a! A a!y%i% "$ Gr"u di ( Sy%'e)-6/The figure shows two earthembedded conductor

segments of length A7 / andlength A7 A.

%roblem / (oltage at point$ x,y,z & due to flow of the

current I /.

%roblem A (oltage transferred to conductor segment A because of the flow of the current I /.%roblem B (oltage of the conductor segment / due to theflow of its own current I /.

8ue to above problems we need to know the (oltage8istribution *actor$(8*&,

4etween two x98irected :onductor Segments.4etween an x and y 8irected :onductor Segments.Self (8* of an x98irected :onductor.


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$ $


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$ d


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S"$'#are Va!ida'i"

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Sr. No. 5/antit a$/e nit1 a/$t %/rrent 1 A2 Sho% /ration 0.8 se%3 a/$t /ration 1 se%4 S/r#a%e $a er resistivit 3000 9 . m8 S/r#a%e $a er thi% ness 0.1 m6 Soi$ resistivit 40 9 . m7 'e th o# &ri 0.6 m

en&th in ; ire%tion 63 m

< en&th in = ire%tion 33 m10 on /%tor materia$ #or ro s >in% %oate stee$ ro

Sam $e !ro/n !ri 'esi&n 'ata?3@

S $ id i


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S"$'#are Va!ida'i"

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Par'i*u!ar IEEE3476444 FEMe'+"d ETAPGGSL8 9 Ly ); 63 * 33 63 * 33 63 * 33

N8 9 Ny 21 * 11 21 * 11 21 * 11

R ( "$

T"!erab!e49.43 % 97.37 % 85.65 %

Sa$e'y Safe Safe Safe

S"$'# V !id 'i"


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S"$'#are Va!ida'i"

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'T;% #esults

!S; #esults


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2" *!u%i"

This research describes the development of software named

!rounding System ;naly er that can be used for the designof substation grounding systems. It is capable of analy ing performance of grounding system located in uniform soilswith the help of rigorous analysis method.Sample problem has been solved with this software.:omparison of results obtained using this software with thatgiven by !!S )odule of 'T;% validates the performance ofthis software.

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Fu'ure P!a i (

The software developed gives the analysis of uniform single

layer soil only. So in future the software can be developed forthe analysis for grounding system in the multi layer soil.This software analy es the grounding system with e"uallyspaced grounding grid. In future, software can be designedwhich can analy e une"ually spaced grounding grid.*ault current calculation module also can be added in future.

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R $ * %


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>/= Institute of 'lectrical and 'lectronics 'ngineers, I'''!uide for Safety in ;: Substation !rounding 9 I'''

standard C1, I''', %iscataway, DE, A111.>A= ;.%. Sakis )eliopoulos,F %ower System !rounding and

Transients F $/GCC, Hard9cover&.>B= austubh ;. (yas9-Optimal 8esign of Substation

!rounding Systems-,).Tech. Thesis, Dirma niversity,;hmedabad, A1/A.

Re$ere *e%


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TH;D JO

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4ack up Slides

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s s stouch t C E

/23.1&2.//111$31 +=

s

s s stept

C E /23.1

&0/111$31 +=

s s stouch t C E

//0.1&2.//111$21 +=

s s s step

t C E

//0.1&0/111$21 +=


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TCAP=Thermal capacity of copper Tf= duration of fault currentr =temp co-e cient of resistivityr =Resistivity of conductor material

!= "#A ! at !$ C Tm=%a&' allo(a)leTemperature Tam)=Am)ient Temperature

Df= Decrinment factor*f= *plit factor+f=Total fault current

Ta=DC o,set time constantin sec


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design & development of software for optimized design of grounding system

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