Using a fixed and switched-capacitor bank to investigate harmonic resonance and capacitor bank switching in a distribution network

Abstract

Harmonic resonance often manifests as high harmonic voltages in a power system. This produces losses and affects other consumers in the grid negatively. Capacitance switching applications also involve not only interrupting capacitive currents, but also the energizing of capacitor banks, cables and overhead lines. The applications of capacitors are extensively used in power systems for voltage support and power factor correction. However, the main concern arising from the use of capacitors is the possibility of system resonance. This study investigates the frequent capacitor bank tripping and damages in one of the distribution substations of the Electricity Company of Ghana (ECG). The study was conducted using the Electromagnetic Transient Program (EMTP) software for the simulation. The results showed that, the failures were related to harmonic resonance. Selected series connected inductors were recommended to shift the resonant frequencies of the network below characteristics harmonic frequencies. © Maxwell Scientific Organization, 2014.