Power quality assessment of different load categories

In this paper, a fuzzy logic based method is proposed to define and evaluate power quality indices for different categories of electricity consumers. The severity level of each power quality disturbance is first estimated according to the frequency of its identification or some other metrics including percentages of voltage imbalance, total harmonic distortion rates, and durations and varying ranges of certain types of disturbances. With the constitutions of a regional power load being analyzed, a power quality index is then computed for each category of electricity end-users based on the severities of the identified disturbances and their impacts to each particular load type. It is believed that such an index will help utilities assess power quality comprehensively so as to improve their services to meet variable requirements from different electricity customers. Some data based on site measurements are used to demonstrate the proposed method in calculating the defined power quality index.