September 25th

Laboratory of Distributed Generation in Institute of Electrical Power Engineering of Technical University of Lodz

In the paper major laboratory equipment is described: photovoltaics, microturbine, fuel cell, battery energy storage, together with the configuration of the laboratory network facilitating studies of characteristics of those energy sources and problems of cooperation of distributed generators with electrical power network. For integration of distributed sources into the power system it is necessary to properly control their operation.

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Distributed Generation Impact on Voltage Sags in Distribution Networks

Characteristics of voltage sags caused by faults in distribution networks depend on the design of the protection system and the coordination between the different protective devices. The presence of distributed generation (DG) changes the radial nature of distribution systems, so it can affect the performance of the protection system, and consequently the characteristics of voltage sags. In addition, DG will help to maintain the during-fault voltages of healthy phases.

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Inductive Decoupling of Low-Voltage Sub-Networks

Voltage control in networks with predominantly resistive coupling is most efficient when controlling the active power flow. By introducing a series connected inductor for a dedicated part of the network the coupling can be shifted to the inductive type. Hence the voltage in such sub-networks can be influenced by injection of reactive power. Furthermore harmonic distortions present in the main grid are reduced.

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September 22nd

Eco-sheet: 1 kWh generated using different energy sources

How sustainable is a kWh? What is the best technology to produce it? These questions are often asked and the answers are not clear-cut, as there are a lot of variables.

Therefore, Leonardo ENERGY has produced this eco-sheet to help clarifying the issue. The environmental burden of generating one kWh from 7 different energy sources is quantified. It shows that there is no silver bullet solution, but there are advantages to explore.

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Design and Testing of a Low Cost Peak-Power Tracking Controller for a Fixed Blade 1.2 kVA Wind Turbine

Wind turbines are a common source of electrical power generation in rural sites around the world. The power generated by a wind turbine at a given wind speed is a non-linear function of rotor speed. This results in a specific rotor speed for maximum power production at each wind speed. A control system incorporating a Pulse Width Modulated DC -DC converter has been designed to vary the load on the wind turbine thereby forcing it to operate at its maximum power point.

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Electromagnetic Coupling of the Electrical Drive - EMC (Part II)

The paper deals with the general analysis of one part of the electromagnetic compatibility (EMC ) problem — the electromagnetic coupling applied in the field of power electrical systems as. The simulation analyses and practical measurements of the electromagnetic coupling are presented in part II . Obtained results confirm the correctness of the theoretical analyses and so they can be used for predictive stating of EMC quality of individual new electrotechnical products.

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Diagnostics of Commutator DC Motor Basing on Spectral Analysis of Signals

Measurement investigations have been carried out for commutator dc motor with internal asymmetries. Construction of considered motor enables to realize the breaking of one rotor coil and shorting of two groups of rotor coils. Each group contains three rotor coils. The basis of study were signals: current and voltage of field winding, current and voltage of armature winding and velocity of the rotor.

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September 17th

Problems of Practical Diagnostics of Induction Machines in Industry

There are many problems in practical diagnostics of high-power, quirrel-cage induction machines, operated in industrial conditions. These problems make the diagnostics a difficult matter. The problems appear already at the stage of gathering diagnostic signals. The only practically accessible signals are the currents on secondary sides of current transformers monitoring supply currents of separate machines.

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An Improved Model of a Three phase Induction Motor Incorporating the Parameter Variations

A great deal of work is being done on the improvement of control through simulation of the electric drives used for various high-power purposes. The authenticity of the simulated results is based on the accurate modeling of the various parts of the electric drive system.

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September 15th

A New Closed Loop Speed Control Strategy for a Vector Controlled Three- Phase Induction Motor Drive

This paper presents a model based mathematical equations for control of torque and speed of a three-phase indirect vector controlled VSD-fed induction-cage motor that is controlled through the space vector modulated method. This enables a wide range of acceptability of the model for various values of load and various types and ratings of induction motors.

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