8/19/2019 Cable Sizing With Clarifications1111111

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 Proj.No. :

1361

BUILDING (40) rev 0

CABLE NO.: F-SMSB.40.G.1

destination route/type load

From : AIR 0.380 kVTo : XLPE 238 kW

Length : 150 m 0.8 p.f.

Design Current , Ib = Max. Dem. KW = 452 A

3 x kV x p.f.   TO IEC STANDARD.

Nearest Nominal AT , I 500  A .   630  AF frame .

  BREAK ER SIZING 

Correction Factor,C.F.= Ca x Cg x Cf x Ci (Ca= 1 for ambient temperature) Sewedy p. 15

= 1 x Cg x 1 x 1 (Cg= 0.91 for grouped cables) Sewedy p.17, 18

= 0.91 (Cf=1, for cables protected by C.B.)

(Ci=1, for uninsulated installation)

target Ampacity, It = Ib = 452 = 497  A

C.F. 0.91

Select Cable Size: ccc >= It

ccc = 404 A for S = 185 mm  -- Sewedy p. 63  AIR

use 497   2 // cables x 185 mm multicore

404 808 A ( catalog ccc )

Sending End S.E.Imped.(in milli Ohms) = 3.48

Derated Ampacity , Iz= CCC x C.F  + Cable Cab.Imped.(in milli Ohms) = 10.44=   735  A ------>> Receiving End R.E.Imped.(in milli Ohms) = 13.92

R.E.Symm.Fault (in kA) =   15.77

CHECK PROTECTION CRITERIA : (=kV*1000/sqrt(3)*R.E.Imped.milli Ohms)

1- That Iz >= In , or ,

735 >= 500   SUCCEED .

CHECK VOLTAGE DROP CRITERIA :

1- Individual V.D. :V.D.1 = mV/A/m / # cables x Ib x L

= 0.241 x 452.4 x 150 mV -> Sewedy p. 23 XLPE

2

= 8.177 V

= 2.152 %

2-  Accumulated V.D. :

Acc V.D.= V.D.1 + V.D. on upstream cable

= 2.152 + 0.024 % ---->

=  2.176 % (Should be