Search results for "Power"
showing 10 items of 5099 documents
Effect of voltage deviations on power distribution losses in presence of DG technology
2015
Integration of distributed generation (DG) units in power distribution network has become increasingly attractive multi-faceted paradigm as economic and environmental factors drive new technologies to be more efficient and less polluting than their earlier counterparts. The installation of DGs impacts critically on the planning and operating characteristics of the distribution network. Type, location, number and capacity of DG are essential factors for studying the effect of DGs on the system behavior. In this paper the effect of DG on the power losses of a distribution network is investigated for different types of DG units. Also, the impact of DG on the voltage profile is demonstrated bef…
Verifying the effect of distributed generators on voltage profile, power losses and protection system in radial distribution networks
2013
In the recent years the electrical power networks are undergoing rapid restructuring and developing process worldwide. Advancement in technologies and concern about the environmental impacts have led to increase interconnection of renewable energy based distributed generations (DGs) in distribution networks. The DGs have significant impacts on the distribution systems; these impacts may be either positively or negatively depending on the modified interconnected DG distribution network structure. It will be necessary to consider many issues concerning these impacts. In this paper, an investigation of DGs impacts on voltage profile, power losses, and protection system in radial distribution n…
Tuulimyllyjä vastaan? : ei enää tohtorikoulutettavia
2019
Pääkirjoitus Editorial
Dialoga secības izkārtojums Oskara Vailda lugā “Ideāls vīrs”
2016
Analizējot dramaturģiskus darbus, īpaši vērts aplūkot dialoga secības izkārtojumu. Šie literārie teksti lielākoties sastāv no mutvārdu diskursa, tāpēc veids, kā runātāji savā starpā virza un attīsta sarunu, daudz atklāj par atainoto situāciju. Šajā Bakalaurā darba analizēts dialoga secības izkārtojums Oskara Vailda lugas “Ideāls vīrs” fragmentā, kurā sarunājas lugas divi galvenie personāži, Sers Roberts Čilterns un Misis Čevelija, lugas pirmajā cēlienā. Ņemot vērā, ka analīzei izvēlētais fragments ataino šantāžu un izspiešanu, pētījums koncentrēts uz to, kā dialoga secības izkārtojums atklāj spēku samērus starp personāžiem. Analīzes procesā izmantota kvalitatīvā metodē, toties metodoloģija …
Real-Time Minimization Power Losses by Driven Primary Regulation in Islanded Microgrids
2020
Islanded microgrids are small networks that work independently from the main grid. The frequency and voltage in islanded microgrids are affected directly by the output power of distributed generators and power demand variations. In this work, a real-time driven primary regulation, which relies on optimized P-f droop coefficients, is proposed. In all operating conditions, it minimizes the power losses for islanded microgrids. The proposed configuration will allow the optimization modules to interact with each other and adjust parameters producing a suitable power sharing among generators. The methodology is tested based on a hardware-in-the-loop experimental set-up where distributed generato…
‘I was excited to train, so I didn’t have problems with the coach’: dual career athletes’ experiences of (dis)empowering motivational climates
2019
In addition to investing in athletic development, adolescent elite athletes are expected to complete their secondary education. As a result of this expectation and the demands of sport and education, they may struggle to sustain high levels of motivation for both domains. Grounded in theoretical tenets of empowering coaching, this study sought to explore student–athletes’ perceptions of empowering and disempowering motivational climates and their possible implications for athletes’ dual career experiences. Semi-structured interviews were conducted with 17 Finnish student–athletes, and the data were thematically analysed. The analysis indicated that a majority of the athletes had experiences…
Impact of the high share of converter-interfaced generation on electromechanical oscillations in Continental Europe power system
2020
This study investigates the effects of converter-interfaced generation integration on the dynamic response of the power system of Continental Europe. The system is analysed with a large-scale dynamic model of the entire synchronous area, considering different instantaneous integration percentages of converter-interfaced generation across the system. The study focuses on the reduction of the overall available kinetic energy and the impact on frequency dynamics and system oscillations. The dynamic model of the system originally provided by ENTSO-E is further developed according to a specific methodology, replacing a determined amount of synchronous generation and introducing a corresponding a…
Inter-area oscillations in the 500-kV Vietnamese power system
2019
The paper presents the study of the 500-kV Vietnamese power system. The oscillatory response of the system is analyzed both with a modal analysis and a time domain analysis. The 500-kV system of Vietnam is modeled in details, including all the power plants with the corresponding regulators. The model is developed in collaboration with the Institute of Energy Science IES-VAST of Vietnam and it is validated with the data provided by the National Load Dispatch Centre (NLDC) of Vietnam. The simulation results reveal a clear identification of potential inter-area oscillations between North and South of the Country. A worsening of the observed phenomenon should be considered as possible, especial…
Transient stability simulation of a fixed speed wind turbine by Matlab/Simulink
2007
This paper describes the dynamic behavior of a typical fixed speed wind turbine connected to the grid; the model is developed in the simulation tool Matlab/Simulink and created as a modular structure. The pitch control system is used for stabilization of the wind turbine at grid faults. In this way, voltage stability of the system with grid-connected wind turbines can be improved by using blade-angle control for a temporary reduction of the wind turbine power during a short-circuit fault in the grid. This paper shows a new variable control for maintaining of voltage stability, when a three-phase fault is applied close to the wind turbine and cleared by disconnecting the affected line. In th…
Considering safety issues in minimum losses reconfiguration for MV distribution networks
2009
This paper offers a new perspective over the traditional problem of the multiobjective optimal reconfiguration of electrical distribution systems in regular working state. The issue is indeed here formulated including also safety issues. Indeed, dimensioning the earth electrodes of their own secondary substations, distribution companies take into account the probable future configurations of the network due to transformations of overhead lines into cable lines or realization of new lines. On the contrary, they do not consider that, during normal working conditions. the structure of the network can be modified for long periods as a consequence of reconfiguration manoeuvres, with differences …