الفهرس Only 14 pages are availabe for public view
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Abstract
Power Quality is becoming an issue of increasing concern both to the utilities and their customers. A power quality problem can be described as any variation in the electrical power service, such as voltage sags, swells, interruption, harmonics, notches and fluctuations resulting in mis-operation or failure of end-use equipment.
The aforementioned disturbance, degrading the reliability and quality of the power supply, though always existed on utility systems are nowadays causing more and more troubles. This is due to the increased refinement of today automated equipment, such as variable speed drives, automated production lines, programmable logic controllers, and power supplies in computers. These equipments are far more sensitive to disturbances on the utility system than previous generation of electromechanical equipment and less automated production and information systems.
To improve the electric power quality, sources of disturbances must be known and controlled. This can done by first detecting, localizing and classifying different disturbances. Load management system was installed at E.C. W Company in 1998. This system was able to record phase currents, phase voltages, TIID, crest factor, low resolution raw wave data, and power factor. Hundreds of plots have been recorded along over year 2003 and year 2004. These parameters were recorded for different company feeders with the goal of load monitoring.
In order to fulfill the power quality assessment for EL-Nahas Working Company, the existing power system for the company is first introduced. Then a monitoring study is carried out to have a measurements-based idea of power quality level. The main feeders (7 feeders), which have non-linear loads and high rate of switching are monitored for four days. Monitored parameters include voltage variation, current variation, power factor variation, voltage THD variation, frequency deviation, voltage unbalance variation, voltage harmonic spectrum, current harmonic spectrum, short term flicker, and long term flicker. Input feeders are also monitored as a point of common coupling between the ECW company and the electrical distribution company.
Monitored parameters are compared to IEEE standards limits and violation of these limits is diagnosed. Analysis of the results is introduced with recommendation of future work.
In chapter (5), we will show the filters is design to eliminate harmful harmonics by powerex software. And a modified approach. That is for over limit measurement.
In chapter (6), we will show conclusion and future study in brief.