Power system harmonic resonance: a documented case

Harmonic resonance occurs in a power system when the power system´s natural frequency corresponds to the frequency of a source of harmonic current. A case of power system harmonic resonance which resulted in failure of 13.8 kV switchgear and consequential plant losses is documented. Calculations of the power system´s natural frequencies are given for various power system configurations of supply reactance, motor reactance, and system-shunt capacitance. Sources of harmonic current are identified, methods of measuring harmonic current and voltage levels throughout the system are described, and results of the power system harmonic current and voltage survey are reported. The corrective action taken to prevent a recurrence of harmonic resonance is also described.<>