Capacitor Banks in an Asynchronous Generator Power Plant

A photo of a messy interconnection of a three-phase power capacitor bank installed in a 460 V, 360 kW asynchronous or induction generator used in a mini hydro plant. Each capacitor has a kVar output enumerated in the nameplate which varies depending on the generator output voltage and frequency. The rationale behind that varying kvar output is that the Kvar output of a condenser or capacitor is a function of the voltage across it and its capacitive reactance, KVar = V^2/Xc. The capacitive reactance on the other hand is a function of the frequency, with capacitance as constant, and given by the following formula; Xc = 1/j*2*pi()*f*C

Example:
Frequency: 60 Hz
Capacitance: 3 x 154 microfarad = 462 microfarad
Voltage across: 480 V

Xc = 1/jwc f= -1/(2*3.1416*60*462micron) = - 5.74 ohms
Kvar = VI = V^2 / Xc = - 480^2/5.74 = - 40.139 Kvar

The negative sign indicates that the reactive power is being supplied by the device.

Related Post/Articles:
What are the content of a power capacitor name plate?
What is the function of a capacitor in an electric power system?

Posted in Electrical Machines

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