The main goal of this paper is the determination of the effect of the metal oxide varistor (MOV) on various ferroresonance modes including fundamental resonance, subharmonic and chaos mode which are generated in electrical power systems. Chaos theory is used for analyzing this effect. Also, the bifurcation, phase plan diagram and time domain simulation are used for this purpose. The proposed po...

Since power transformer is a complex and critical component of the power transmission and distribution system, their reliability is crucially important for the energy system operation. So, there is an increasing interest in applying monitoring systems and on line diagnosis methods to transformers, as these are one of the most expensive and critical apparatus of a power system. Detecting failure...

There are some deficiencies in the improved three-ratio method even though it has been widely used in power transformer fault diagnosis. Using artificial neural networks, the power transformer fault diagnosis is improved in this article. With Matlab programming, three different kinds of neural networks, which are Radial Basis Function (RBF) neural network, Learning Vector Quantization (LVQ) neu...

Sweep frequency response analysis is a major advance in transformer condition analysis. Frequency response is performed by applying a low voltage signal of varying frequencies to the transformer windings and measuring both the input and output signals. The ratio of these two signals gives the required response. This ratio is called the transfer function of the transformer from which both the ma...

Partial discharge inside a transformer is mainly responsible for the insulation aging and damage of the transformer. However, partial discharge is usually accompanied by external signals like sound, light and electrical signals and detectable physical phenomena such as characteristical gas and dielectric loss. Therefore, it is of great significance to monitor online the external signals and phe...

A differential LC-VCO that adopts a transformer with asymmetric turns-ratio has been proposed. The asymmetric turns-ratio of the transformer leads to the suppression of the AM to FM conversion which is caused by the 1/f noise of the current source transistor. The analysis of the proposed scheme and the improvement in phase noise compare to conventional CMOS LC-VCOs are described. The transforme...

This paper presents a new approach to identify distributed parameters of a lumped-element model for a power transformer. A simplified circuit of a lumped-element model is developed to calculate frequency responses of transformer windings in a wide range of frequency domain. In order to seek optimal parameters of the simplified circuit of the transformer, an intelligent learning technique, based...

The purpose of this paper is to present and discuss a general HV topology of the solid-state Marx modulator, for unipolar or bipolar generation connected with a step-up transformer to increase the output voltage applied to a resistive load. Due to the use of an output transformer, discussion about the reset of the transformer is made to guarantee zero average voltage applied to the primary. It ...

The purpose of this study was to investigate the balance abilities of the adolescent girl with brain lesions by Sit-to-Stand (STS) action analysis before and after the rehabilitative horse riding of 16 week program. The subject aged 16 yr old who had the disabilities of spasticity and hemiplegia was recruited with the consent approval. The equilibrium abilities of the subject were tested by Sit...

We give a decision procedure for the theory of the weak truth table wtt degrees of the recursively enumerable sets The key to this decision procedure is a characterization of the nite lattices which can be embedded into the r e wtt degrees by a map which preserves the least and greatest elements A nite lattice has such an embedding if and only if it is distributive and the ideal generated by it...