A fuzzy expert system for quantifying voltage quality in electrical distribution systems

Power quality is usually taken as a voltage quality. When the impacts on voltage quality are known, some information about power quality can be obtained. Various types of device connected to power distribution systems expect good voltage quality, but their expectation levels may differ. Device sensitivities to the voltage quality problems are usually given with the curves. Commonly used for the computer systems is the CBEMA curve. Using device sensitivity characteristics can be a reasonable way to represent voltage quality. CBEMA curve strictly separate acceptable — unacceptable regions, and should be fuzzied. Different methods can be tried for evaluation of voltage quality. Because of including vagueness and uncertainty voltage quality has chance to be studied with fuzzy mathematics. Voltage quality problems can be separately examined. If the effect of each individual problem on voltage quality is known, then general voltage quality can be considered as superposition of individual voltage qualities. In this work, a method was proposed for quantifying the voltage quality. To achieve this, software was written using Matlab and its Fuzzy Toolbox.