The objective of this research is to compute the mechanical stresses in power transformer resulting from the currents more than rated value during its operation. Due to this high fault current, mechanical stresses are produced indifferent directions which may cause the damage of winding insulation. Various techniques have been adopted to analyze the stresses on transformer windings. For the acc...

In the paper a novel approach to overcurrent protection stabilisation based on Fuzzy Logic technique is presented. The scheme is intended for MV overhead lines for which the autoreclosure function is applied to enhance reliability of supply in case of intermediate (vanishing) faults. Protection stabilisation is required for the feeders supplying a part of network with numerous loaded MV/LV tran...

The squared-field-derivative method for calculating eddy-current (proximity-effect) losses in round-wire or litz-wire transformer and inductor windings is derived. The method is capable of analyzing losses due to two-dimensional and three-dimensional field effects in multiple windings with arbitrary waveforms in each winding. It uses a simple set of numerical magnetostatic field calculations, w...

The squared-field-derivative method for calculating eddy-current (proximity-effect) losses in round-wire or litz-wire transformer and inductor windings is derived. The method is capable of analyzing losses due to two-dimensional and three-dimensional field effects in multiple windings with arbitrary waveforms in each winding. It uses a simple set of numerical magnetostatic field calculations, w...

The methodology and test results of a three-phase three-column transformer with Dy connection group are presented in this paper. This study covers the dynamics events that took place first period transient state caused by energizing under no-load conditions. origin inrush currents was analyzed. influence factors accompanying switch-on impact model parameters on distribution maximum values these...

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...

For there are few samples of water inrush from coal floor, how to dig wider information under the circumstance of limited sample data is to improve the prediction accuracy of water inrush form coal floor. Therefore, prediction model of water inrush is established based on correlation analysis and support vector machine (SVM). Not only does the model simplify the influenced indexes to construct ...

Photovoltaic systems integrated to the grid have received considerable attention around the world. They can be connected to the electrical grid via galvanic isolation (transformer) or without it (transformerless). Despite making galvanic isolation, low frequency transformer increases size, cost and losses. On the other hand, transformerless PV systems increase the leakage current (common-mode c...

proper operations of transformer have several issues such as; preventing of unscheduled removal’s, increasing of reliability and continues supply of consumer demand. this result would be obtained that load and harmonic orders of sensitivity transformer at intervals appropriate for next hours and days is predicted to by selecting optimal utilization coefficient, reduction life of transformer is ...