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Abstract:In this paper, a dynamic model is developed for high-voltage circuit breakers to extract fault features and causes. Lagrange's method is applied using geometric equations of mechanism components to write the model.Unlike previous approaches, the proposed method reveals and analyzes all types of circuit breaker operating mechanism faults. Early fault detection, which is a vital requirement of the fault diagnosis system, becomes feasible by keeping track of changes in the contact travel curve in the proposed model. Resulting faults in the travel curve are analyzed mathematically in order to find out the exact origin of the fault. Field test results show the accuracy and reliability of the fault detection method.

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Summary The main aim of this paper is to design an active fault tolerant controller for switched positive linear systems. A theorem is proved for fault and state estimation of switched positive linear systems in terms of matrix inequality by considering average dwell‐time approach. By utilizing the theorem results, not only a fast and exact estimation of fault and state is obtained but also the positivity of state estimation is ensured. The feasibility problem is solved by formulating it into a special sequential optimization problem subject to LMI constraints. Based on the fault estimation information, an observer‐based fault tolerant control guaranties the stability and positivity of the closed‐loop system. Finally, a practical example including a data communication network is presented to illustrate the efficiency of the proposed method.

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