Page 820 - Industrial Power Engineering and Applications Handbook

Power caoacitors: behaviour, switching and improvement of power factor 23/775
I,,, = peak inrush current in parallel switching r = mean radius of the coil in cm
V, = line to neutral peak voltage rl = radius of the cross-section of the coil in cm
Determining the kVAr rating for improving p.f.
(ii) Switching frequency from cos 4, to cos 42

kVAr, - kVAr2 = kW(tan q5, - tan &) = kW.K (23.17)
(23.14)
L,, = equivalent inductance of the capacitors already
switched Further reading
LZeq = L,, + L,
C,,, = equivalent capacitance of the capacitors already I AIEE Committee. Report 017 the Operation of Switched
5 witched Cupucirors, Vol. 74, Part Ill, 1255-1261. December (1955).
C, = capacitance of the capacitor being switched 2 Central Board of Irrigation and Power, 1ndia;Interference of
power lines with telephone lines’ Technml Report No. 29.
Research Scheme on Power, March (1982).
Limiting inrush currents 3 ‘Cigre, Harmonics voltage unbalanced voltage dips and voltage
fluctuations’. Study Committee 36, ’Interference,’ Working
c, ’ c, Group 36.05, Published by Electra, March (1989).
(23.15) 4 Johnson, LB., Schultz, A.J., Schultr. N.R. and Shores. R.B..
’Some fundamentals on capacitance switching‘. AIEE
Trunsuctions. 727-736, August (1955).
I,:, = improved inrush current 5 Narasimha, G., ‘Capacitor switching and its effect on LT
L = series inductance being introduced switchgear’, Electrical India, 5-8, 30 November (1982).
V,, = line to neutral peak voltage 6 Savir-Silbermann, S., ‘Surges caused by switching of capacitor
banks’, Electrical Energ?; 88-95. March (1958).
7 Sharma. S.P., ‘Switching capacitor banks in L.T. switchgear’,
Designing an inductor to limit the inrush IEEMA Journal, September (1989).
currents 8 Shenoy, G., ‘Reducing harmonic currents and improving powel-
factor in installations having predominant thyristor loads’,
Siemens Circuit, XVII, No. 1 (1982).
9 Vansickle, R.C. and Zaborszky. J., ’Capacitor switching
phenomena’. AI€€ Trun.saction.s, 70, Part I, 151-159 (195 I).
IO Vansickle, R.C. and Zaborszky, J., ‘Capacitor switching
L = self-induced inductance of the coil in henry phenomena with resistors’. AIEE Trmscrcrion.~. 97 1-977. August
N = number of turns of the coil (1954).