Investigating university personnel computers (PC) produced harmonics effect on line currents

Nonlinear loads connected to a sinusoidal source inject harmonic currents into the source. Nonlinear load is a load that draws none sinusoidal current wave when supplied by a sinusoidal voltage source. Much attention has been focused on large power converters as sources of harmonics due to the high magnitude of the currents evolved. Nevertheless, harmonics generated by low power converters become significant when large numbers of converters are used simultaneously. In this paper the influence of the personal computers in the line current harmonics in some buildings at King Fahd University of Petroleum and Minerals (KFUPM) have been investigated. The harmonics were monitored from the main switched boards of each building that has the highest number of PC’s and from the switch boards of each computer labs in these buildings. This investigation may help in pinpointing the harmonic generating sources, effects, and how to mitigate, also to obtain the actual PC operation of the university and its harmonic contribution. Measurements indicate that two buildings of the highest PC's numbers do have harmonics but one building harmonics is higher than that allowed by IEEE-519 standards [1] limits and the other does not influence phase current and it is within allowable limits.