The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
In recent years generation of electricity using wind power has received considerable attention worldwide. Induction machines are mostly used as generators in wind power based generations. Since induction machines have a stability problem as they draw very large reactive currents during fault condition, reactive power compensation can be provided to improve stability. This paper deals with the Impact...
A voltage source inverter with variable frequency and variable voltage is applied for three-phase interior permanent magnet synchronous motor (IPMSM) drive for variable speed application. To obtain the required output voltage in the line side of the inverter a suitable pulse width modulation technique is used. The most prominent PWM techniques are Sinusoidal pulse width modulation (SPWM) and Space...
The development of electric and hybrid vehicles has gained increasing attention in recent years. This paper proposes an Electric drive for Hybrid vehicles application and its control strategy to achieve a wide speed range. In these vehicles, important requirements for the electric drive are low weight, small volume, high efficiency and low cost. When choosing the motor for the vehicle drive, the induction...
This paper presents a novel method for the estimation and minimization of losses in a radial distribution system with distributed generation. Due to the increasing power demand and importance of renewable energy sources in recent times, the studies on integration of distributed generation to the power grid have been rapidly increased. The sources referred as distributed generation (DG) are added to...
This paper presents a novel m ethod for evaluating Power flow in a radial distribution networks. Conventionally power flow algorithms used consider real and reactive power to be independent of node voltage which is not always true in case of distribution systems. Voltage sensitive nature of load imparts a considerable amount of influence over actual amount of power flowing in the system. A forward...
This paper presents a new Adaptive Mutation Particle Swarm Optimization algorithm for minimization of losses of a Reconfigured Distribution Network. The tendency of solution being struck up to local optima or premature convergence as in the case of conventional PSO is thoroughly avoided using this new proposed technique. The algorithm is based on variance of population's fitness. During running time,...
In this paper, a simplified space vector pulse width modulation (SVPWM) method has been developed for three-phase three-level voltage source inverter fed to direct torque controlled (DTC) induction motor drive. The space vector diagram of three-level inverter is simplified into two-level inverter. So the selection of switching sequences is done as conventional two-level SVPWM method. Where in conventional...
In this paper, a linear programming algorithm is proposed for determining a measure of market concentration in congested transmission systems. The linear program uses the effects of congestors on system to derate line limits of each transmission line. The linear program uses transmission line constraints with derated line limits, generation constraints to calculate maximum SIC for group of buyers...
This paper presents the speed torque characteristics of BLDC motor on load in forward and reverse direction. The Hall sensors of the BLDC motor is bestowed as the input to the ARM controller. The PWMs are produced depending upon the input of the controller. In order to convert DC to three phase AC, three phase bridge inverter with MOSFET as switches is used. The generated PWMs are inputted to the...
Based on 245kV GIS substation, very fast transient over voltages caused by disconnecting switch operation of GIS is simulated and calculated in this paper with B2SPICE program. The different protection measures are compared and analyzed, such as adding ferrite rings, adding opening and closing resistor, metal oxide arrester and R-C absorber. A low voltage experiment was conducted to estimate transient...
The transient high frequency electric and magnetic fields are generated in Gas insulated substations (GIS) systems during switching operations by both radiation and conduction mechanisms. In this paper the radiated transient electric and magnetic fields are measured by using high frequency field sensors at important locations in the 245kV GIS were presented. The measurements are carried out at three...
Very fast transient over voltages are generated during the switching of disconnectors in gas insulated substation (Gas Insulated Substation). Such over voltages can cause mal functioning of protection circuits and control circuits and also initiates faults and influence on other components such as transformers. The suppression of VFTO (Very fast transient over voltage) is very important in GIS systems...
Very fast transient over voltages (VFTO) and very fast transient over currents (VFTC) are generated during switching operation of disconnectors in Gas insulated substation (GIS). In this paper the accurate GIS model has been developed and VFTO'S and VFTC'S were estimated at bushing termination using EMTP program. The wavelet analysis of VFTO and VFTC signals have been carried out and frequency spectrum...
The transient high frequency electric and magnetic fields are generated in Gas insulated substations(GIS) systems during switching operations by both radiation and conduction mechanisms. In this paper the radiated transient electric and magnetic fields are measured by using high frequency field sensors at important locations in the 245kV GIS were presented. The measurements are carried out at three...
The major threat to Gas insulated Bus duct is presence of metallic particle contamination in the form of loose particles. This may be present on the enclosure, HV conductor or on the spacer. In this paper conducting contaminant trajectory is obtained for particulate on the spacer with SF6 gas dielectric medium. Wire like metallic contaminants of length 10mm with 0.25mm radius of copper, Aluminum and...
Very fast transient over voltages (VFTO) and very fast transient over currents (VFTC) are generated during switching operation of disconnectors in Gas insulated substation (GIS). In this paper the accurate GIS model has been developed and VFTO'S and VFTC'S were estimated using EMTP program. The wavelet analysis of VFTO and VFTC signals have been carried out and frequency spectrum of VFTO wave form...
The main cause for the most of the failures in Gas Insulated Busduct is attributed to the presence of metallic particle contaminations in the form of loose particles, which may exist on the inner surface of outer enclosure of GIB or on HV conductor. These conducting particles under the influence of high voltage may acquire sufficient charge and randomly move in the inter electrode gap due to variable...
Transient over voltages due to lightning and switching surges cause steep build-up of voltage on transmission lines and other electrical apparatus, like circuit breakers, transformers, insulators etc. Therefore it is necessary for the GIS also to withstand such voltages without breakdown of insulation. The system has to be tested under these conditions. Usually the GIS system operates on power frequency...
Compressed gas insulated substations (GIS) consist basically of a conductor supported on insulators inside an enclosure, which is filled with sulfur hexafluoride gas (SF6). The voltage withstand capability of SF6 bus duct is strongly dependent on field perturbations such as those caused by conductor surface imperfections and by conducting particle contaminants. The particles can be lifted by the electric...
Metallic particle contamination in a compressed gas insulated busduct (GIB) or system (GIS) may lower the corona onset and breakdown voltage of the system considerably. These particles move randomly in a horizontally mounted GIB system due to the electric field, and this movement plays a crucial role in determining the insulation behavior of gas insulated substations. Under 50-Hz AC voltage, the particle...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.