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Modern power systems are prone to widespread failures. With the increase in power demand, operation and planning of large interconnected power system are becoming more and more complex, so power system will become less secure. Operating environment, conventional planning and operating methods can leave power system exposed to instabilities. Voltage instability is one of the phenomena which have result...
Reducing dead time of high voltage power transmission lines is one of the most important issues in power system protection. Besides, need for reducing the dead time is a matter of grave concern to increase voltage level of power transmission lines and insulation coordination. In this paper, different methods for decreasing the capacitive coupling and consequently reducing the dead time of power transmission...
At a single-phase short-circuit on the 110 kV side of the transformer station the value of the current closing through the equivalent grounding electrode of the city or the industrial plant depends, to a great extent, on the position of the electrode relative to the 110 kV line which feed the fault. In the paper the influence of some parameters which affect the value of the short-circuit current which...
Today fuel cells are finding use in everything from cell phones to automobiles. Regardless of their application the fuel cell must be accurately modeled in the system it will be used. Such model has to be simple, easy to use and fast to simulate. Chemistry, material science and physics should be transformed in electrical components and systems that can be easily implemented in programs like SPICE,...
Distribution network reconfiguration (DNR) is a crucial issue in the operating horizon of distribution systems. In distribution networks tie switches will be changed to obtain an appropriate network configuration with minimum losses. Distribution networks have hundreds of switches and determining the best status of switches is a complicated combinatorial, non-differentiable constrained optimization...
The paper presents a new technique to mitigate the voltage unbalance in LV distribution grids using distributed generation (DG). Usually, public LV networks supply many single phase consumers; in this case, the unbalanced line currents produce the unbalance of standard symmetrical supply voltage system. This voltage system negatively influences other three-phase loads operating in the same system,...
This paper proposed control of static VAR compensator (SVC) for improvement of voltage profile with fuzzy controller that tuned with genetic algorithm. Our method integrated two design stages; determinations of membership function and rules consequent parameters, because these stages may not be independent, it's important to consider them simultaneously to obtain optimal fuzzy systems. We present...
Within this paper we present a model of elaboration of National Qualification Framework and Study Programs for engineers' training on the basis of a competitive approach, European Credit Transfer System (ECTS), and the demands of the new higher educational structure on cycles: Bachelor-Master-Doctorate (B-M-D). This model constitutes the basis of all study programs in engineering domains proposed...
This paper deals with an educational experiment of teaching basic knowledge on electromagnetic structure of synchronous electrical machines, standard operation and testing and parameters evaluation based on finite element models and analyses.
In this paper, we consider the mobility effect with a jointly optimal design of cross-layer congestion control, routing and scheduling for ad-hoc networks. We first formulate the rate constraint and scheduling constraint. In this way, we use multi-commodity flow variables. Then formulate resource allocation in networks with fixed wireless channel and single-rate devices. Because of entrance of the...
Power system oscillation damping, have always been an undeniable problem for engineers. In this paper we try to show that a supplementary lead-lag controller using wide area signals can greatly decrease the oscillations, because the global signals involve more wide-area oscillation modes. Parameters of this damping lead-lag controller are obtained by phase compensation method. Then an artificial neural...
This paper presents a novel strategy for the vector control of IPMSM, without signal injection. The overall performance of the motion-sensorless control depends strongly on the accuracy of the rotor position and speed estimation. The proposed state observer is based on the concept of the ldquoactive fluxrdquo (or ldquotorque producing fluxrdquo), which ldquoturns all the salient-pole rotor ac machines...
The paper summarizes the actual applied and new proposed techniques in the domain of the AC-line conditioning. The advantages of the line conditioning with the help of the PWM DC converters are presented. After that is briefly discussed the principle of the complex power factor correction, as an intermediate solution between the presently applied simple line conditioning methods and the formerly investigated...
The goal of the paper was to analyze the current distribution of a high-power salient-pole synchronous machine damper winding. A few methods were considered but only two analytical methods are highlighted. Both methods arc based on parameter calculation by considering the bars of the damper winding grouped in symmetrical loops referred to the direct and quadrature axis. Based on the developed procedures...
The following topics are dealt with: electrotechnics; power electronics; electric machines; electric drives; renewable energy conversion and control; industrial automatics and control; applied electronics; electrical engineering education.
This paper studies the frequency control in an islanded micro-grid (MG) supplied by Renewable Energy Sources (RES). The MG contains two generators, a synchronous generator, an induction one, and loads. Frequency stabilization is obtained by using a hybrid solution with a dump load (DL) and an energy storage system (ESS) based on a battery bank. The generators available power and the loads demand gives...
This paper presents an implementation and compatibility tests of an advanced hybrid (wireless- wired) entertainment network (server+multiple clients) implemented using coaxial cable, conventional Ethernet and WiFi technologies. This architecture takes into account the ldquohome gatewayrdquo concept present in many implementations solving the problem of the ldquointelligent homerdquo. The overall presentation...
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