The choice of optimum cross section for overhead line by economic intervals' method

The choice of optimum cross section for overhead line by economic intervals' methodIn this paper an approach to choosing the optimum cross section for overhead line in conditions of incomplete and uncertain information is considered. The two methods of such choice are presented: method of economic current density and economic intervals' method. The correction of the economic intervals method is offered under market conditions of costs. As example 20 kV and 110 kV overhead lines with aluminum, copper and ferroaluminum wires are selected. Universal nomograms with different standard cross section are calculated and constructed. The graphics using Mathcad software are offered.

Basic Statements of Research and Magnetic Field of Axial Excitation Inductor Generator

Basic Statements of Research and Magnetic Field of Axial Excitation Inductor GeneratorIn this work the main features of axial excitation inductor generators are described. Mathematical simulation of a magnetic field is realized by using the finite element method. The objective of this work is to elucidate how single elements shape, geometric dimensions and magnetic saturation of magnetic system affect the main characteristics of the field (magnetic induction, magnetic flux linkage). The main directions of a magnetic system optimization are specified.

Lossless Dynamic Models of the Quasi-Z-Source Converter Family

Lossless Dynamic Models of the Quasi-Z-Source Converter FamilyThis paper is devoted to the quasi-Z-source (qZS) converter family. Recently, the qZS-converters have attracted attention because of their specific properties of voltage boost and buck functions with a single switching stage, which could be especially beneficial in renewable energy applications. As main representatives of the qZS-converter family, the traditional quasi-Z-source inverter as well as two novel extended boost quasi-Z-source inverters are discussed. Lossless dynamic models of these topologies are presented and analyzed.

Intelligent Transformer: Possibilities and Challenges

Intelligent Transformer: Possibilities and Challenges This paper covers the concept of an intelligent transformer that is a good candidate to replace a conventional low frequency transformer in the microgrids. As the power production and consumption can vary in a wide range, the new substations have to meet many requirements to guarantee reliable energy management in the autonomous networks. Different topologies of intelligent transformers can be used to meet these requirements. Therefore the advantages and disadvantages of the existing topologies were analyzed. The future trends and challenges are also discussed.

Market Based Analysis of Power System Interconnections

Market Based Analysis of Power System InterconnectionsAnalysis in this Article is focused on usage of transmission grid under liberalized market with implicit transmission capacity allocation method, e.g. Nordic market. Attention is paid on fundamental changes in transmission utilization and its economical effective operation. For interconnection and power flow analysis and losses calculation model of Nordic grid was developed and transmission losses calculation method was created. Given approach will improve economical efficiency of system operation in electricity market conditions.

Electromechanical Battery, Electrical Machines Mass Functions Analysis

Electromechanical Battery, Electrical Machines Mass Functions AnalysisIn this paper different types of electrical machines in electromechanical battery, were described. The most known manufactured battery data is composed. Three types of machines: synchronous machine with salient poles and electromagnetic excitation, with permanent magnets on rotor and reluctance synchronous machine were analyzed. For all types of machines, mass is function of general geometrical size of magnetic system and machines electrical power.

Model for Technical-Economic Analysis of ENTSO-E and IPS/UPS Power System Optimal Interconnection Concepts

Model for Technical-Economic Analysis of ENTSO-E and IPS/UPS Power System Optimal Interconnection ConceptsThis paper considers the analysis of large-scale power system optimal interconnection concept as well as description of the model for evaluation of its costs and benefits. Paper contains the method for technical-economic analysis of different scenarios of interconnection of two world largest power systems - ENTSO-E and IPS/UPS. The research has shown that developed model is capable to make deep analysis and is ready for calculation of interconnection links optimal locations, transmission capacities and interconnection type.

Estimation of Economical Validity of Usage Remote Operated Disconnectors for 110kV Switchgear Schemes From Optimal Reliability Level Point of View

Estimation of Economical Validity of Usage Remote Operated Disconnectors for 110kV Switchgear Schemes From Optimal Reliability Level Point of ViewThe paper gives results of technical and economical calculations performed for estimation of validity of usage remote operated disconnectors for most commonly used 110kV switchgears from optimal reliability level point of view. Paper contains description of performed technical calculations - calculations of 110kV switchgear schemes' reliability level depending on type of disconnectors installed, and economical calculations, that are related with additional costs of Transmission System Operator and changes in total customer costs of power supply interruptions.

The Model of Nonstationary Rotor Magnetic Field Observer in the Induction Motor

The Model of Nonstationary Rotor Magnetic Field Observer in the Induction Motor This article is devoted to the questions, associated with observer construction for monitoring the values of rotor magnetic vector magnitude and angular deflection of induction motor oriented on bidimensional convolution on temporal and spatial actual parameters. The interrelation of induction motor breakdown torque and rotor characteristic time and transportation lag is shown. The system of rotor running stream observer on the basis of gage rotor position and stator current is put forward.