Investigations of power quality problems in modern buildings

Abstract

This thesis presents the results of measurements made in a typical office building (Tower A) and a Residential building (Kilmorey Hall), all located in the campus of Brunel University, West London for period of one week. The collected data were statistically treated to establish the best period that characterizes the harmonic distortions and other disturbances in these buildings. The chosen period was considered as best to get the correct harmonic distortions in the day, and at a specific interval. One phase was also chosen to represent the others after some considerations.

The frequency of measurement was also noted. All the data collected were evaluated based on the limits proposed by International Standards: European, IEEE, and G4/5 Recommendations. Comparisons of the collected data were made between these two buildings. For the purpose of this project, the statistical treatment of the collected data characterizing the voltage harmonics was considered. The period of 9am to 5pm on a week day (Tuesday 26th October) was best for Tower A as it had the highest loading pattern for the week. This is a day-load establishment, because it is an office building. The period for Kilmorey Hall was Monday 1st November between the hours of 6pm up to 11pm, being considered as wholly residential building. All readings were spaced at 8minutes interval for frequency of measurement.

The methodology presented in this project is useful for quantification and qualification of the harmonic distortion of voltage and current. It is estimated that more than 30% of the power currently being drawn from the utility companies is now consumed by sensitive non- linear load, and still increasing, both industrially and commercially [20]. Non- linear load is steadily increasing in residential areas also. The effect of continuous overvoltage was also considered even though the overvoltage was within the International Standards. The result was proved to cause unnecessary and unwanted overconsumption. This could not be helping to reduce carbon emission.

Effects of Compact Fluorescent Lamps with electronic gears (CFLs) were also investigated as a rising source of harmonic production in Modern buildings.