Question

A 220 kW load having 0.8 lagging power factor is supplied from a 600 V (line to line) three-phase supply. A bank of power factor capacitors is delta connected. (a) Draw neat schematic diagram showing the connection of the capacitor bank in Delta connection. (b) Determine the KVAR rating of each individual capacitor needed to bring power factor to 0.9. (c) Determine the capacitance of each capacitor in uF.

Answer 1

Ans Given, Load power = 220 kw CPD Load power fuctos a 0,8 logging Voltage = 6oov → The schematic diagram bank is shown below. of load with capacitor Goot 50 Hz Load of 220 kw at 0,8 pf lagging

P.f. without compensation les T, = 0,8 => g = cos Co.8) = = 36.86° p.f. orter compensation Cos By = 0.9 = 0,=cost Co.g) → = 25.84° Now Thoce phase reactive power copacitor bank to make p.f. required by shunt from 0.8 to o.g --- - Q = P x (tam de - tam po 2 cap = 220 Ctan (36,86°) - tan (25.86')) = 220 (0.7497 -0.4842) 22305103799 ossesse : Louw Qsanft cap a 58.398 KVAR = ( Now as asment cap. = 3 ve = 3 wapa Ishuntcap = 58.398 KVAR - --- -------- .: 3Vzw Con = 58.398 x103

pn = 58.398 8103 3 x (600)? * 2x50x3.14 (i.e. cpn= Q sumat cap) 3 x V x ot Con = 1.722 X10 4 I Can = 172.2 elf so, be Capacitance 172.2 elf of each plano Capacitor will