Miralem Hadžiselimović

Optimal Distributed Generation placement in distribution network

This paper presents a method for optimal Distributed Generation placement with goal of reducing active power system losses and voltage level regulation. Active power losses in radial distribution network are determined using an Artificial Neural Network (ANN) by simultaneous formulation for the determination process based on voltage level control and injected power. Adequate installed power of distributed generation and the appropriate terminal for distributed generation utilization are selected by means of a genetic algorithm (GA), performed in a distinct manner that fits the type of decision-making assignment. The training data for ANN is obtained by means of load flow simulation performed in DIgSILENT PowerFactory software on a part of the Croatian distribution network. The active power losses and voltage conditions are simulated for various operation scenarios in which the back propagation ANN model has been tested to predict the power losses and voltage levels for each system terminal, and GA is used to determine the optimal terminal for distributed generation placement.

Permanent magnet synchronous motor with exterior‐rotor: Distributed or concentrated windings – motor performance comparison

Purpose – The paper aims to present the comparison between the performances of the exterior‐rotor permanent magnet synchronous motors with distributed windings and the performances of the exterior‐rotor permanent magnet synchronous motors with concentrated windings.Design/methodology/approach – Finite element method is used for motors performance determination. The BLDC operation mode for the motors with different slot and pole number combination and concentrated windings was accounted for in the comparison.Findings – In the BLDC operation mode motor structures with concentrated windings with similar slot and pole numbers exhibit at the same current density similar or even higher torque capability and lower electromagnetic torque ripple in comparison to the motor structure with distributed windings. Motor structures with 9‐slot/8‐pole, 9‐slot/10‐pole, 12‐slot/10‐pole slot and pole number combinations are the most appropriate for the BLDC operation.Originality/value – The paper shows which motor structures...

Magnetically Nonlinear Dynamic Models of Synchronous Machines: Their Derivation, Parameters and Applications

This chapter deals with the magnetically nonlinear dynamic models of synchronous machines. More precisely, the chapter focuses on the dynamic models of the permanent magnet synchronous machines and reluctance synchronous machines. A general procedure, which can be applied to derive such magnetically nonlinear dynamic models, is presented. The model is of no use until its parameters are determined. Therefore, some available experimental methods, that are appropriate for determining parameters of the discussed models, are presented. The examples given at the end of the chapter show, how the magnetically nonlinear dynamic models of discussed synchronous machines can be applied. Generally, in all synchronous machines the resultant magneto-motive force and the rotor move with the same speed. This condition is fulfilled completely only in the case of steadystate operation. However, during the transient operation, the relative speed between the resultant magneto-motive force and the rotor can change. In the case of permanent magnet synchronous machines, the force or torque that causes motion appears due to the interaction between the magnetic fields caused by the permanent magnets and the magnetic excitation caused by the stator currents. On the contrary, in the reluctance synchronous machines the origin of motion is the force or torque caused by the differences in reluctance. Most of the modern permanent magnet synchronous machines utilize both phenomena for the thrust or torque production. A concise historic overview of the development in the field of synchronous machine modelling, related mostly to the machines used for power generation, is given in (Owen, 1999). When it comes to the modern modelling of electric machines, extremely important, but often neglected, work of Gabriel Kron must be mentioned. In the years from 1935 to 1938, he published in General Electric Review series of papers entitled ``The application of tensors to the analysis of rotating electrical machinery.’’ With these publications as well as with (Kron, 1951, 1959, 1965), Kron joined all, at that time available and up to date knowledge, in the fields of physics, mathematics and electric machinery. In such way, he set a solid theoretical background for modern modelling of electric machines. Unfortunately, the generality of Kron’s approach faded over time. In modern books related to the modelling and control of

Battery Pack Design Problems – Influence of the Transverse Magnetic Field on Internal Battery Resistance

The battery pack represents an essential part of electric vehicles (EV), so its design significantly influences the drive characteristics. The system of energy flow control in EV use highfrequency power electronic components that cause the appearance of high harmonics super-imposed on DC component of the battery current. This paper examines the influence of the distribution of the transversal magnetic field inside of the battery pack depending on battery pack design and its influence on battery parameters. DC component of the transversal magnetic field inside of battery cells cause Hall effect ions path allocation that is reflected on internal battery resistance negative change. AC component of the transversal magnetic field in electrically closed loops within battery pack induced e.m.s. that also cause negative phenomena on battery pack parameters.

Monitoring of the solar power plants and performance ratio

This paper deals with monitoring of solar power plants. We can observe solar power plants with energy yield, monitoring or performance ratio. All these approaches of monitoring solar power plants have their advantages and disadvantages. The procedures of monitoring different solar power plants in Slovenia will be presented and evaluated in the paper. It turns out that energy yield and monitoring of solar power plants don’t give enough necessary information concerning proper operation. Energy yield is the ratio between the energy produced and the nominal power of the solar power plant. Energy yield is dependent on the intensity of solar radiation and temperature. It appears that proper operation of solar power plants is best described with the performance ratio, which is the ration between the energy produced and the energy that would be produced at nominal yield. Performance ratio considers the intensity of solar radiation and/or temperature. The results show that the proper operation of the solar power plants is mostly affected by appropriate installation and orientation of solar modules.This paper deals with monitoring of solar power plants. We can observe solar power plants with energy yield, monitoring or performance ratio. All these approaches of monitoring solar power plants have their advantages and disadvantages. The procedures of monitoring different solar power plants in Slovenia will be presented and evaluated in the paper. It turns out that energy yield and monitoring of solar power plants don’t give enough necessary information concerning proper operation. Energy yield is the ratio between the energy produced and the nominal power of the solar power plant. Energy yield is dependent on the intensity of solar radiation and temperature. It appears that proper operation of solar power plants is best described with the performance ratio, which is the ration between the energy produced and the energy that would be produced at nominal yield. Performance ratio considers the intensity of solar radiation and/or temperature. The results show that the proper operation of the solar power p...

The classification of explosion-proof protected induction motor into adequate temperature and efficiency class

This article deals with the classification of explosion-proof protected induction motors, which are used in hazardous areas, into adequate temperature and efficiency class. Hazardous areas are defined as locations with a potentially explosive atmosphere where explosion may occur due to present of flammable gasses, liquids or combustible dusts (industrial plants, mines, etc.). Electric motors and electrical equipment used in such locations must be specially designed and tested to prevent electrical initiation of explosion due to high surface temperature and arcing contacts. This article presents the basic tests of three-phase explosion-proof protected induction motor with special emphasis on the measuring system and temperature rise test. All the measurements were performed with high-accuracy instrumentation and accessory equipment and carried out at the Institute of energy technology in the Electric machines and drives laboratory and Applied electrical engineering laboratory.

Comparison of the Shading Influence on PV Modules of Different Technologies

The characteristics of different PV modules are provided in this paper. The influence of shading on PV module characteristics of different technologies (different crystalline silicon and thin film technologies) is investigated. The study also took into account the orientation of PV modules (portrait or landscape), a by-pass diode number and a type of connections. An inter-row shading factor for different PV modules has also been determined. A comparison of shading influence on PV module characteristics of different technologies has been drawn. A shading factor comparison of different technology PV modules has also been made. The influence of shading on PV system electricity production has been modelled based on a study which examined the influence of shading on characteristics of different technology PV modules.