الفهرس Only 14 pages are availabe for public view
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Abstract
Optimal reactive power and voltage control for distribution system involves the installation of fixed shunt capacitors and tap changing voltage regulators along distribution feeders. This can improve voltage profiles for all end-use customers and reduce real power losses. In this thesis, the fuzzy logic optimization technique is studied and applied to solve the capacitor allocation problem in radial distribution systems. The obtained results are compared with those obtained using fuzzy sets and heuristic techniques in recent publications. Using voltage regulator for voltage control of radial distribution systems is also studied to allow more loss reduction and to improve the whole system voltage profile.
The thesis starts with a study of fuzzy logic as a technique for solving combinatorial optimization problems. The parameters to be specified in any implementation of the technique are also studied.
The applicability of the fuzzy logic technique in the field of capacitor placement problem is discussed. Modifications are made to existing fuzzy membership functions to obtain better results.
An assessment of all fuzzy methods is made using a concept extracted from the truth table of logic circuits. By implementation and comparison with other techniques, this method leads to better results.
Finally, an approach using tap-changing voltage regulators is applied to maintain the voltage profile on a general radial distribution system within a prespecified bandwidth. In addition, the action of the regulators is studied to provide the best possible profile while maximally decreasing system losses; this is done by controlling the regulator tap positions.
The applied approach is implemented and tested on several radial distribution feeders. The results show the superiority of the applied approach to improve the voltage profile and decrease the overall system losses.