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HT Capacitor Bank Calculation

This document provides calculations for sizing capacitors for motor loads at a cement plant. It includes calculations of capacitor kVAR requirements based on motor kW ratings and power factors. It also includes calculations for capacitor bank sizing, reactor sizing and ratings, inrush current, and resonant frequency. Cost estimates are provided for capacitors sized to achieve 0.95 and 0.99 power factors. The capacitors will provide an estimated annual savings of Rs. 2.28 lakhs with a simple payback of 8 years.

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Sankalp Mittal
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5K views5 pages

HT Capacitor Bank Calculation

This document provides calculations for sizing capacitors for motor loads at a cement plant. It includes calculations of capacitor kVAR requirements based on motor kW ratings and power factors. It also includes calculations for capacitor bank sizing, reactor sizing and ratings, inrush current, and resonant frequency. Cost estimates are provided for capacitors sized to achieve 0.95 and 0.99 power factors. The capacitors will provide an estimated annual savings of Rs. 2.28 lakhs with a simple payback of 8 years.

Uploaded by

Sankalp Mittal
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as XLSX, PDF, TXT or read online on Scribd
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HT motors capacitor size calculation- SJHCP

Power factor capacitor KVAR


kW Actual
S. No. HT Motors at 100% =KW(tanØ1-tanØ2) at 6.6
rating KVAR
loading kV

1 Cement mill Fan drive 16291 0.9 5568.75 7200

5875 0.86 2648.88 2500


9135

Cos Ø1 motor pf
Cos Ø2 0.99

Sr no. Application Specifications

1525 KVAR@ 11 kV Capacitor with NCT with 6% series reactor; 2073


1 Cement Mill fan drive
KVAR @ 12.82kV Capacitor with NCT with 6% series reactor
% Series
capacitor KVAR @
Reactor(%
10% overvoltage Require
of
+ 2% SRs i.e 7.41 d KVAr
Capacitor
kV
rating)

9076 2

2975 2

Qty. (Set)

1
Capacitor Bank Calculation
Capacitor & Reactor Calculation
Required kVAr 2975
at Voltage (kV) 7.2
To be designed at Voltage (kV) 6.6
These Datas to be fed for all the
Calculations
% reactor required 6
Double Star or Single Star Double
Rated kVAr at design Voltage= 2500 kVAr

Reactance of 6.6 kV, 2500 kVAr bank, Xc1= 17.43 Ohms

For % reactor , Xc= 16.38 Ohms

Reactor Impedance, XL= 1.046 Ohms

Rated Current of Capacitor Bank, I= 218.7 Amp

Reactor Rating 50.00 kVAr

Final Reactor Rating per Phase 25.000 kVAr

Inrush Current Calculation

For Worst Switching condition for Capacitor Bank rating of 2975 kvar at 7.2 kV

I inrush= Peak L-L System Voltage


√3 * √(Xc1 * XL)

I inrush= 1377 Amps peak

6 times the rated current

Resonant Frequency f

50 * √Xc1
Resonant Frequency, f=
√XL

f= 204 Hz
kVAR requirement at UCC, RAK
Target PF: 0.95 Target PF: 0.99
Sr. No

Name Of Switchgear Required kVar Required kVar Required kVar


Running kW Running PF Running kW Running PF
@ 6.6kV @ 7.2kV @ 6.6kV

1 Kiln Switch gear-1 16291 0.9 2535 3068 16291 0.9 5569
2 Kiln Switch gear-2 16663 0.9 2593 3138 16663 0.9 5696
3 Total Capacitor required 5129 6206 11265

4 Cost of Capacitor at 7.2 kV – 1799729


Considering Rs. 290/- per kVAr
5 Cost of Capacitor (In Rs. Lakhs) 18.00

6 Total Saving envisaged per annum 2.28


(In Rs. Lakhs)–
7 Simple Payback (in Years) 8
quirement at UCC, RAK
0.99
Required
kVar
@7.2kV

6738
6892
13630

3952769

39.5

3.84

10

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