In this paper, a new model based on the thevenin equivalent circuit for investigating the ultra-saturation phenomenon during the energization of a loaded power transformer is presented and its effect on the differential protection of the transformer is considered. The ultra-saturation phenomenon causes the mal-operation of the power transformer differential protection. So, the description a...

An overview of the research and developments into new transformer design, undertaken in the Department of Electrical and Computer Engineering, University of Canterbury, is presented. Initially, single phase, 50 Hz, l1/0.23kV pole mount distribution transformers were fitted with either silicon or amorphous steel cores. The transformer tanks were filled with either standard transformer oil or liq...

This paper deals with three types of power transformer failure analysis tests which can help in monitoring the transformer condition. The three methods are Conventional oil test, Furan derivatives test and Markov models criteria. Conventional oil testing procedure includes determination of gas concentrations in the transformer oil sample and analyzing the fault by considering ratio of two suita...

Classical higher-order logic, when utilized as a meta-logic in which various other (classical and non-classical) logics can be shallowly embedded, is well suited for realising a universal logic reasoning approach. Universal logic reasoning in turn, as envisioned already by Leibniz, may support the rigorous formalisation and deep logical analysis of rational arguments within machines. A respecti...

One of the great benefits of using a stream X-machine to specify a system is its associated testing method. Under certain design for test conditions, this method produces a test suite that can determine the correctness of the implementation under test (IUT), provided that the processing functions of the stream X-machine specification have been correctly implemented. The method was originally de...

OBJECTIVES Previous research has suggested that hemodynamic changes after in utero transfusion may be related to fetal stress. We tested the hypothesis that these hemodynamic changes are more pronounced when the needle is inserted in the fetal abdomen compared with the umbilical cord root. METHODS Most intrauterine transfusions are performed by inserting a needle either in the umbilical cord ...

Stream X-machines are a state based formalism that has associated with it a particular development process in which a system is built from trusted components. Testing thus essentially checks that these components have been combined in a correct manner and that the orders in which they can occur are consistent with the specification. Importantly, there are test generation methods that return a c...

One of transient phenomenon that causes the mal-operation of the power transformer differential protection during the energization of a loaded power transformer is the ultra-saturation phenomenon. In this paper, a new model for investigating the ultra-saturation phenomenon during the energization of a loaded power transformer is presented and its effect on the differential protection of the pow...

This paper proposes a new method to detect transformer inside incipient fault current using transformer internal parameters to determine the inside structure of transformer at good condition or bad. A transformer model was established by Jiles– Atherton theory using measured voltage and current and the initial parameters which were found using Genetic Algorithm (GA). Then, transformer internal ...

In a testing environment, where an IUT communicates with multiple entities, a tester may have di ering degrees of controllability on the interactions between these entities and the IUT: directly controllable, semicontrollable, or uncontrollable. In this paper, a graph conversion algorithm is introduced that o ers the testability of both the directly and semicontrollable inputs, while avoiding r...