A study on randomly varying harmonic currents and total harmonic distortion of currents in power systems

Harmonic analysis is an important application to power systems and an efficient approach to evaluate the injected total harmonic distortion (THD) of currents flowing into a power system due to the summation of randomly varying harmonic currents produced by AC-to-DC power converters is presented in this paper. A probabilistic model is established to derive the magnitude of the injected harmonic currents using the expected value and variance of the harmonic current sources. The simulated results using Monte Carlo simulation are compared with the ones of the proposed approach to validate the proposed scheme. This paper presents the analyzed results of statistical harmonic currents generated by ten AC-to-DC power converters with 4 different ranges of firing angle. The individual harmonic currents and total harmonic distortion of currents generated by converters are also examined