Vague Set Based Power System Stabilizer

Abstract

The power system is a dynamic system and is constantly being subjected to newlinedisturbances. It is important that these disturbances do not drive the system to unstable newlineconditions. For this purpose, additional signal derived from speed deviation, excitation newlinedeviation and accelerating power are injected to voltage regulator. The device to provide newlinethese signals is referred as power system stabilizer (PSS). newlineThe conventional PSS which uses lead lag compensation where gain settings are newlinedesigned for specific operating condition. Therefore, it is very difficult to design a stabilizer newlinethat could present good performance in all operating points of electric power system. In an newlineattempt to cover a wide range of operating conditions, Fuzzy logic controller has been newlinesuggested as possible solution to overcome this problem, thereby using linguist information newlineand avoiding a complex system mathematical model, while giving good performance under newlinedifferent operating conditions. newlineIn the present work a Vague Controller (VC) is synthesized by using the notion of newlineVague sets, which are a generalization of Fuzzy sets, synonyms of the Interval type fuzzy newlinesets and characterized by a truth-membership function and a false membership function. newlineThe Vague sets follow the basic set operations and logic operations defined for fuzzy sets, newlineand are better than fuzzy sets in that they could deal with the uncertainty encountered in newlinereal-world applications in a more natural way. A Vague set based Controller has been newlinedesigned to control the power system stabilizer. The proposed Vague set Controller based newlinePower System Stabilizers is designed (VCPSS). In the proposed Vague expert system, newlinespeed deviation and its derivative have been selected as Vague inputs. The stabilizing newlinesignals were computed using the Vague membership function depending on these variables. newlineThe proposed Vague set Controller based Power System Stabilizer (VCPSS) newlinediscussed in Para 3 above has been evaluated on a single machine and multi machine newlineinfinite bus power systems.