Vektorski upravljani elektromotorni pogoni s reluktantnim sinkronim motorima uz definiranu dinamiku zatvorenog kruga brzine vrtnje

A new speed control system for electric drives employing reluctance synchronous motors is presented. Design control system combines two control methods. Conventional vector control method is here completed with forced dynamics closed-loop control. Since the closed-loop system response is a first order lag whose pole location can be chosen by the user, the drive may be included as an actuator in a larger scale control scheme to which linear control system design methods can be applied. To improve robustness of the design control structure, the outer control loop based on model reference adaptive control is added. Simulation results presented show good correspondence with theoretical predictions and MRAC outer control loop improves overall drive performances.Prikazana je nova koncepcija sustava upravljanja brzinom vrtnje elektromotornog pogona s reluktantnim sinkronim motorima, temeljena na dvijema metodama upravljanja. Konvencionalna vektorska metoda nadograđena je elementom sustava koji predstavlja dinamiku zatvorenog kruga po brzini vrtnje. Budući da je dinamika zatvorenog sustava prikazana proporcionalnim članom prvog reda, čiji pol odabire korisnik, predložena koncepcija može biti šire primjenjiva. Da bi se poboljšala robusnost sustava, dodana je vanjska petlja upravljanja zasnovana na adaptivnom upravljanju s referentnim modelom. Simulacijski rezultati prikazani u radu potvrđuju valjanost predložene koncepcije

Management of voltage quality in Slovak power system

The reqested voltage value is one of the main indicators of the delivered electric energy quality. The energy transfer system has to secure the good-quality electric energy deliveri for all consumers in the time when the electric energy market is opened. This paper showns the voltage analysis possibilities as well as the proposal for supply system voltage values improving by modern compensating means

Possibilities of genetic algorithm application in the calculation of power networks operation

The paper describes the possibilities of genetic algorithm application by the reactive power flows’ optimization in Slovak power transmission system. The methods of reactive power flow calculation and the utilization of genetic algorithms for their minimalization are indicated in the paper. There are the results of calculated voltages and reactive power flows presented in chart and graphical format at the end of this paper

New possibility of lines power flow control

Present time is characteristic with increasing requests of consumers on the quality and quantity of delivered energy. In regard to financial and time difficulty of building up new power plants and distribution lines, producers and distributors must find out more a effective capacity utilization of the actual equipment. There is the place for installing the new systems FACTS – unit for the control and regulation of power flows in energetic lines, and also to limit the reactive flow in lines

Hodnotenie účinnosti regulácie napätia

Článok pojednáva o základoch regulácie napätia v pilotných uzloch ES Slovenska. Analyzuje z hľadiska denných, mesačných a ročných priemerov uzlové napätia na úrovni 220 a 400 kV v rozvodniach prenosovej sústavy Slovenska. Na základe vyhodnotenia smerodajnej odchýlky napätia je hodnotená účinnosť regulácie napätia v jednotlivých uzloch. V závere článku sú zhrnuté výsledky analýzy v grafickej forme

Management of Voltage Quality in Slovak Power System

The reqested voltage value is one of the main indicators of the delivered electric energy quality. The energy transfer system has to secure the good-quality electric energy deliveri for all consumers in the time when the electric energy market is opened. This paper showns the voltage analysis possibilities as well as the proposal for supply system voltage values improving by modern compensating means

Photovoltaics in Present Days and Their Coexistence with Power System

The article deals with the issue of presentation of photovoltaic power and photovoltaic power plants, describes their main features, their advantages and disadvantages, and also deals with the possible massive deployment of these power sources to the power system and their impacts on power system operation

The Influence of Power Quality Indices on Active Power Losses in a Local Distribution Grid

This paper deals with the topic of power quality in a local distribution grid. It is aimed to analyze the individual influences, which aggravate the power quality of the distribution grid. Based on the analysis, the most adverse effects were determined, and they were the voltage drops and supply voltage interruptions, supply voltage unbalance, load power factor, and also higher harmonics. These influences cause the technical losses in a distribution grid, which subsequently have a financial impact not only on the distribution, but also on the transmission of electricity. Only the load voltage unbalance, the load power factor, and the higher harmonics, which mainly cause the technical losses, were analyzed in this paper. The measurement of the influences of the adverse effects was performed on the model of a 22-kV distribution grid. The measurement was performed on the basis of three types of power line conductors and their different lengths, three types of active power consumption, and the different values of these adverse effects. According to this measurement, a simulation in program Matlab-Simulink was created. This simulation represented part of a 22-kV distribution grid, which was influenced by the abovementioned adverse effects. The results of the measurements were compared with the results of the simulation. Based on the evaluation of the technical losses from the measurement and the simulation, the financial losses during a certain period were calculated for the distribution system operators

Complex power quality evaluation of electrical energy in electric networks

Power quality evaluation is in the scope of research activities carried out by the members of Department of Power Electrical Systems (KVES) for many years. Results presented in the paper are the outcomes of number of accomplished measurements and analyses. They point out the importance of EMC assessment in the points of common coupling in electric networks