ABSTRACT
With the increase in consumer nonlinear load, the harmonics injected into the power supply system and their consequent effects are becoming of greater concern. Harmonic currents seeking a low impedance path or a resonant condition can travel through the power system and create problems for the consumers who do not have their own source of harmonic generation. The system frequency may change, causing harmonic frequency to change. The tolerance on filter reactors and capacitors may change due to aging or temperature effects. Closer tolerances on the components are an option but that may not be practical and economically justifiable. Capacitors with metalized film construction lose capacitance as they age, resulting in a gradual increase in the tuning frequency. The operation of an internal or external fuse or shorting of elements of a fuseless capacitor bank changes the capacitance of the filter and subjects it to higher overvoltage.
