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Earthing Calculation IEEE2000

The document discusses the calculation of a grounding system for a 150 kV substation. It outlines standards and literature used, and calculates the minimum required size of grid and downlead conductors to safely conduct fault currents using formulas that consider factors like current duration, material properties, and temperature. Copper conductors with cross-sectional areas of 240 mm2 for the grid and 2 x 240 mm2 for the downleads were selected based on the calculations.

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Bravery Damanik
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140 views2 pages

Earthing Calculation IEEE2000

The document discusses the calculation of a grounding system for a 150 kV substation. It outlines standards and literature used, and calculates the minimum required size of grid and downlead conductors to safely conduct fault currents using formulas that consider factors like current duration, material properties, and temperature. Copper conductors with cross-sectional areas of 240 mm2 for the grid and 2 x 240 mm2 for the downleads were selected based on the calculations.

Uploaded by

Bravery Damanik
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PDF, TXT or read online on Scribd
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PALU-3 COAL FIRED STEAM

POWER PLANT (2 x 50 MW)


CONSORTIUM
PT.PLN Persero WIKA-DHI-KOEN
DOCUMENT NO. Rev. : B
CALCULATION OF GROUNDING SYSTEM FOR
18JE05-CAL-AE-3001-0007 150 kV SUBSTATION Page No. : 4 of 12

A. STANDARD AND LITERATURE


1. IEEE Std 80-2000, IEEE Guide for Safety in AC Substation Grounding

B. CONDUCTOR SIZING

B.1 Grid Conductor


Layout arrangement of the individual conductor of the mesh type earthing enables branching of fault
current to minimum two sections in any point of connection between downlead earthing conductor
and mesh type earthing grid. Due to this, 60% of the total single pole short circuit is meritory for
calculation for the cross section of the mesh type earthing conductor.

For,
short circuit level (taken for grounding design) : 40 kA
and,
splitting/branching factor : 60 %
then,
If = 3Io (Ground fault current for conductor sizing): 24.000 A

With tc given,
tc (duration of fault current for conductor sizing) : 1s
and having the material constants
ar : 0,0038
rr : 1,786 mW/cm
TCAP factor : 3,422 J/cm3/0C
K0 : 242
o
Tm : 1084 C
o
Ta : 40 C

the minimum grid conductor size can be calculated :

1
A mm 2  I
4
 TCAP  10   K 0  Tm 
  ln  
 t c r  r   K 0  Ta 
Amm2 = 86,02 mm2
2
Consequently it is selected copper conductor with cross section area: 240 mm
and d (diameter) : 17,49 mm

Current density ID check :


ID = If / A 24.000/ 240 = 100 A/mm2
ID < 200 A/mm2 -->OK
PALU-3 COAL FIRED STEAM
POWER PLANT (2 x 50 MW)
CONSORTIUM
PT.PLN Persero WIKA-DHI-KOEN

DOCUMENT NO. Rev. : B


CALCULATION OF GROUNDING SYSTEM FOR
150 kV SUBSTATION
18JE05-CAL-AE-3001-0007 Page No. : 5 of 12

B.2 Downlead Conductor


Calculation of minimum downlead conductor size with the following material constants :

ar : 0,0038
rr : 1,786 mW/cm
TCAP factor : 3,422 J/cm3/0C
K0 : 242
o
Tm : 1084 C
o
Ta : 40 C
and,
maximum fault current : 40 kA

giving result :
Amm2 = 143,36 mm2

Then BC 2 X 240 mm2 is selected as downlead conductor.


and d (diameter) : 17,49 mm

Current density ID check :


ID = If / A = 24.000 / 480 mm2 = 50 A/mm2
ID < 200 A/mm2 -->OK
OK

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