The objective of the elec...

Power systems are designed to operate at nominal frequencies of 50 Hz or 60 Hz. However, certain types of loads produce currents and voltages with frequencies that are higher than the nominal, resulting in the following: voltage and current distortion, low voltage notching, communication systems interference and high voltages and currents in case of resonance. Harmonics can also cause relay malfunction, programmable logic controller (PLC) interference, capacitor fuse interruptions and high overall system losses. Moreover, the interruption of a capacitive current causes dielectric problems for the switching device. The major concern arising from the use of capacitors is the possibility of system resonance which is one of the main consequences of harmonics in power systems. This paper investigates the frequent capacitor bank tripping and damages in a distribution substation of the Electricity Company of Ghana (ECG) with the aid of a fixed capacitor bank. The study was conducted using the Electromagnetic Transient Program (EMTP) software for the simulation. The results showed that, the damages and failures had a direct bearing with harmonic resonance. Carefully selected series-connected inductors were recommended to move the resonant frequencies of the network below characteristics harmonic frequencies. The significance of the study is to investigate the effect of harmonic resonance o