Linguistic Display of Status of System to Support Distribution Sub-Station Operator

This paper presents a new method of analyzing the distribution system under uncertain variations in the loads. The measured load variation data collected from a practical radial distribution system have been modeled as Type-2 Fuzzy Sets, which represents the uncertain variations in the load. The developed Type-2 membership function models have been validated using Mambdani-FIS by computing the centroid values of voltages at each bus (Consequent) for the centroid values of Type-2 fuzzy set modeled as load at each bus (Antecedent) and these values are compared with voltages obtained by normal power flow solution for the centroid values of the load. Further the authors proposes a new Linguistic Display Aiding Tool for the Substation Operator, by displaying the status of Voltage Drops, Line Flows in each branches of the Feeder and Laterals Linguistically where the substation operator gets the display of the status in his local language. For which the authors uses a similarity measuring method between the standard type-2 fuzzy sets labeled with linguistic words and the Type-2 fuzzy sets of voltages at each bus or the voltage drops in each branches of the laterals or the losses in each line. The measures of uncertainty such as centroid, cardinality, fuzziness, Skewness and Variance of the IT2 FS of loads and voltages are computed. These are useful to compute two types of uncertainties associated with a word: intra-personal uncertainty and inter-personal uncertainty.