The reenement calculus, based on predicate transformer semantics, is proving useful in the construction of sequential programs. It is argued that the reenement calculus provides a suitable development formalism for (possibly real-time) dataaow-like processes. Conventional precondition and postcondition speciications of sequential programs are generalised to assumption and eeect speciications of...

In this paper we study generic expansions of predicate logics of some left-continuous t-norms (mainly Gödel and Nilpotent Minimum predicate logics) with a countable set of truth-constants. Using known results on tnorm based predicate fuzzy logics we obtain results on the conservativeness and completeness for the expansions of some predicate fuzzy logics. We describe the problem for the cases of...

In accordance with intelligent complementary strategies, a new transformer fault diagnosis method is proposed based on rough set (RS) and fuzzy set (FS) and Bayesian optimal classifier in this paper. Through RS reduction, the diagnostic decision table is greatly simplified and fault symptoms information is compressed, dramatically, and the minimal decision rules can be obtained. In the light of...

Power Transformers are a vital link in a power system. Well-being of power transformer is very much important to the reliable operation of the power system. Dissolved Gas Analysis (DGA) is one for the effective tool for monitoring the condition of the transformer. To interpret the DGA result multiple techniques are available.IEC codes are developed to diagnose transformer faults. But there are ...

Risk assessment for power transformer is an important means to guide the condition based maintenance of transformer and enhance the reliability of power system operation, but also to strengthen the power transformer to provide an important basis for quality control. In this paper, an index system for comprehensive evaluation of transformer is put forward and a risk assessment model for power tr...

This paper presents a new approach for classifying transient phenomena in power transformers, which may be implemented in digital relaying for transformer differential protection. Discrimination of various operating conditions of the power transformer is achieved by combining wavelet transform with Adaptive Neuro Fuzzy Inference system (ANFIS). The wavelet transform is applied for the analysis ...

This paper emphasizes on the use of fuzzy approach in dealing with the incipient fault conditions of power transformer. DGA (Dissolved Gas in Oil Analysis) cannot provide better fault diagnosis results when multiple faults are involved. The boundary values specified by the ratio methods are of limited concern .Considering the limitations of convergence of the conventional neural networks in the...