2140-108-27-EN-PVE-U-001-02
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Transcript of 2140-108-27-EN-PVE-U-001-02
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------ Original Message --------
Subject:TR::029 Submission of Revised VFD Reactor & Transformer SizingCalculations Rev.02-Korba STPP
Date:Tue, 05 Feb 2008 08:52:27 +0530
From:RAMA MOHAN.G
To:[email protected], 'N K Gupta' ,[email protected]
Bharat Heavy Electricals Limited Fax : 080-26741953( A Government of India Undertaking ) 26740137
ELECTRONICS DIVISION : 080-26998259PB No. 2606, Mysore Road, Bangalore - 560 026 26745150
REF:CE:PMC:KORBA-III:GRMTo, 05.02.08
Shri TAPAS DEYDGM (I/C- Kh Korba & Farakka Task Force)NTPC/EOC Complex Fax: 0120-2410217Plot No. A8A , Sector 24NOIDA : 201 301 (UP)
ATTN: Shri KS RAMASWAMY / CDE (TF Korba/Farakka)Dear sir,
Sub.: Submission of Revised VFD Reactor & Transformer Sizing Calculations Rev.02-
for KORBA III 1X500MW
Please find enclosed the VFD REACTOR & TRANSFORMER SIZINGCALCULATIONS Rev.02 dtd.21.01.2008(2140-108-27EN-PVE-U-001-02 Descal.pdf)
for NTPC KORBA III 1x500MW.
The following are the changes in Rev.02
a.Calculations have been done with 12 Pulse Motor rating changed to 3900KW as given
by BHEL Bhopal. b.VFD Transformer rating has been revised to
3250KVA,6.6kV/2.3kV against earlier rating of 3000KVA,6.6kV/2.3kV to match the
rating of VFD Transformer for Farakka St-III 1x500MW.
Rev.01 of the above document has been given Cat-IV approval by NTPC vide transmittalRef.:CC:PEK:2140:108102:27:561 dtd.27.02.07 enclosed herewith.
With the above, we request NTPC to kindly approve the above document at the earliest.
Thanking You,
Yours faithfully,
mailto:[email protected]%3emailto:[email protected]:[email protected]:[email protected]%3emailto:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]%3emailto:[email protected]:[email protected]%3e -
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For BHARAT HEAVY ELECTRICALS
LTD.
G.RAMAMOHAN
Dy. Manager PMC/CE
Copy to::
L.SubbalakshmiDy.Mgr(CE-D&PS)
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PROJECT : VFD FOR NTPC-KORBA STPP ST-III (1X500MW)
DOCUMENT NO: D&PS/NTPCKORBA/DESCAL/REV.02 Date : 21.01.2008
DC LINK REACTOR & TRANSFORMER RATING CALCULATIONS (NTPC-KORBA VFD)
PAGE 1 :DC REACTOR SIZING ( RATING) CALCULATIONS:NTPC Drg . No: 2140-108-27EN-PVE-U-001 REV02
BHEL Drg No : EN-DG-2410-145-4052
FROM MOTOR SPEC/DATA SHEET:
TEST BLOCK PT: DESIGN POINT 1: ( 3900KW , 545 RPM) : 12 PULSE RATING
IAC1 = 3900 = 566 Amps
2* 3 * 2.3 * 0.96 * 0.90 (Taking 0.96 eff. & 0.9 lead p.f)
IDC1 = 1.2825 * IAC1 = 1.2825 * 566= 726 Amps
BMCR-DC RATING: (1475 KW, 390 RPM) : 6 PULSE RATING
IAC2 = 1475 = 558 Amps
3 * 1.804 * 0.94 * 0.90 (Taking 0.94 eff. & 0.90 lead p.f)Motor Terminal Voltage at BMCR Pt = 1.804KV
IDC2 = 1.2825 * IAC2 = 1.2825 * 558= 716 Amps
IDC MIN = 0.2 * IDC2 = 0.2 * 716= 143 Amps
DC Reactor is required to absorb : ( * 2 * 2300) * 1/600 volt-sec= 1.355 volt-sec
Inductance value = 1.355/143 = 9.48 mH
Take 10 mH
Current rating = 726 * 1.2 = 871 amps (20% for ripple)
Take 1000 amps
Reactor Rating = 10 mH , 1000 amp s
KVAR Rating of Reactor = (2fLI) * I * 10 3
= (314 * 10 * 103 * 1000) * 1000 * 10 3= 3140 KVAR
Assume 0.7 % losses in reactor: 0.7 * 10 2 * 3140 = 22 kW
Voltage drop across reactor = 22 * 10 3 = 22 volts
1000
Digitally signed byN.K. GUPTADN: cn=N.K.GUPTA, c=IN,o=NTPCLTD,ou=TASKFORCE,email=nkgupta@nt
pceoc.co.inReason: CAT-IVDate: 2008.02.1511:27:49 +05'30'
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PAGE 2 :TRANSFORMER SIZING (RATING) CALCULATIONS:
NTPC Drg . No: 2140-108-27EN-PVE-U-001 REV02BHEL Drg No : EN-DG-2410-145-4052
Keeping a margin angle of 25% for Inverter operation:
(+) = 155 = 180 - ( - ) ( - ) = 25
= 39 , = 14 (XT = 12%, XS = 0.5%)
DC Voltage on motor side of reactor :
= Cell drop + 1.35 * ELL (cos + Xc/2 + Rm)
[ Reactance = 0.10 (Xc) ; Rm = Ra = 0.012 ]
= 9 + 1.35 * 2300 ( 0.78 + 0.05 + 0.012)= 2623 volts
Voltage on converter side of DC Link Reactor := 2623 + 22 = 2645 volts [Drop across reactor = 22 volts]
Assuming a 5% dip on mains :
0.95 EDO = 2645 + [(XT + XS)/2 + RT] * EDO + 9= 2645 + [(0.12 + 0.005)/2 +0.01] * EDO + 9
0.8775 EDO = 2654 EDO = 3025 volts
Transformer Secondary voltage = 3025 /1.35 = 2240 voltsTake 2300 volts
Transformer Rating = 1.05 * EDO * IDC= 1.05 * ( 1.35 * 2300) * 726 * 10-3
= 2367 KVA ( XT = 12%)
Taking into consideration transformer losses, add 20% to KVA 1.2 * 2367 =2840 KVA
Take 3250 KVA
Transf orm er Rating = 6.6 KV / 2.3 KV, 3250 KVA
Flexible Couplin g : Type PM 270 (Renold Hi-Tec Coupling)
Prepared By Checked By Approved By
(L.Subbalakshmi) (Prachi Rao.V) (S.K.Iyengar)
