Original scientific paper Measurement of grid voltage harmonic components is an important part of power quality measurements. Current high voltage transformers with iron core are not linear and cannot easily be used for accurate measurement of "polluted" voltages in wide frequency range. In this paper, design details of a new coreless voltage transformer for power quality measurement are given....

A high voltage capacitor is relatively frequently switched during the periods of the system operations. The distribution transformers are subjected to many stresses during normal and abnormal operations. In this paper we simulate a portion of the distribution network of Durgapur Steel Plant using MATLAB 7.7 and observe the effects of capacitor switching events on transformer terminal at differe...

A two stage model is used to model the high frequency transient behavior of two winding transformers. The assumed transformer model’s parameters are estimated using the maximum likelihood estimation technique and the Kalman filter based on the time response data. Simulations are carried out using the frequency response data generated based on an assumed transformer model. The transfer function ...

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...