scholarly journals Load Flow Equivalents for Decentralized Monitor and Control of Power Systems

1992 ◽  
Vol 112 (12) ◽  
pp. 1129-1138
Author(s):  
Kazuyuki Tanaka
Author(s):  
Ajith M ◽  
Dr. R. Rajeswari

Power-flow studies are of great significance in planning and designing the future expansion of power systems as well as in determining the best operation of existing systems. Technologies such as renewables and power electronics are aiding in power conversion and control, thus making the power system massive, complex, and dynamic. HVDC is being preferred due to limitations in HVAC such as reactive power loss, stability, current carrying capacity, operation and control. The HVDC system is being used for bulk power transmission over long distances with minimum losses using overhead transmission lines or submarine cable crossings. Recent years have witnessed an unprecedented growth in the number of the HVDC projects. Due to the vast size and inaccessibility of transmission systems, real time testing can prove to be difficult. Thus analyzing power system stability through computer modeling and simulation proves to be a viable solution in this case. The motivation of this project is to construct and analyze the load flow and short circuit behavior in an IEEE 14 bus power system with DC link using MATLAB software. This involves determining the parameters for converter transformer, rectifier, inverter and DC cable for modelling the DC link. The line chosen for incorporation of DC link is a weak bus. This project gives the results of load flow and along with comparison of reactive power flow, system losses, voltage in an AC and an AC-DC system.


1998 ◽  
Author(s):  
Michael Jones ◽  
Carlos Carrion ◽  
Elin Klaseen

2021 ◽  
Vol 59 (1) ◽  
pp. 1-20
Author(s):  
Cédric Jourde ◽  
Marie Brossier ◽  
Muriel Gomez-Perez

ABSTRACTThis article analyses how the state in Senegal has managed the hajj since the liberalisation era in the early 2000s. Although the essence of the hajj is religious, it is also deeply political and requires that the state manages complex relations with pilgrims, religious leaders, private travel agencies, politicians and Saudi authorities. This article argues that three inter-related imperatives structure the conduct of the Senegalese state: a security imperative, a legitimation imperative, and a clientelistic imperative. Security concerns lead the state to monitor and control pilgrims travelling to Mecca. Legitimation is seen in the collaborative relations with Sûfi orders and in the framing of the hajj organisation as a ‘public service’. Finally, given the magnitude of financial and symbolic resources attached to the hajj, clientelistic relations are constitutive of state officials’ actions. Overall, despite the post-2000 liberalisation of the hajj, the state has maintained its role as a gatekeeper, regulator and supervisor.


Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 4060
Author(s):  
Artur Kozłowski ◽  
Łukasz Bołoz

This article discusses the work that resulted in the development of two battery-powered self-propelled electric mining machines intended for operation in the conditions of a Polish copper ore mine. Currently, the global mining industry is seeing a growing interest in battery-powered electric machines, which are replacing solutions powered by internal combustion engines. The cooperation of Mine Master, Łukasiewicz Research Network—Institute of Innovative Technologies EMAG and AGH University of Science and Technology allowed carrying out a number of works that resulted in the production of two completely new machines. In order to develop the requirements and assumptions for the designed battery-powered propulsion systems, underground tests of the existing combustion machines were carried out. Based on the results of these tests, power supply systems and control algorithms were developed and verified in a virtual environment. Next, a laboratory test stand for validating power supply systems and control algorithms was developed and constructed. The tests were aimed at checking all possible situations in which the battery gets discharged as a result of the machine’s ride or operation and when it is charged from the mine’s mains or with energy recovered during braking. Simulations of undesirable situations, such as fluctuations in the supply voltage or charging power limitation, were also carried out at the test stand. Positive test results were obtained. Finally, the power supply systems along with control algorithms were implemented and tested in the produced battery-powered machines during operational trials. The power systems and control algorithms are universal enough to be implemented in two different types of machines. Both machines were specially designed to substitute diesel machines in the conditions of a Polish ore mine. They are the lowest underground battery-powered drilling and bolting rigs with onboard chargers. The machines can also be charged by external fast battery chargers.


Author(s):  
Shenghu Li

The induction generators (IGs) are basic to wind energy conversion. They produce the active power and consume the reactive power, with the voltage characteristics fragile compared with that of the synchronous generators and doubly-fed IGs. In the stressed system states, they may intensify var imbalance, yielding undesirable operation of zone 3 impedance relays.In this paper, the operation characteristics of the zone 3 relays in the wind power systems is studied. With the theoretical and load flow analysis, it is proved that the equivalent impedance of the IGs lies in the 2nd quadrature, possibly seen as the backward faults by the mho relays, i.e. the apparent impedance enters into the protection region from the left side. The undesirable operation may be caused by more wind power, larger load, less var compensation, and larger torque angle.


Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3680
Author(s):  
Lasantha Meegahapola ◽  
Siqi Bu

Power network operators are rapidly incorporating wind power generation into their power grids to meet the widely accepted carbon neutrality targets and facilitate the transition from conventional fossil-fuel energy sources to the clean and low-carbon renewable energy sources [...]


2011 ◽  
Vol 20 (07) ◽  
pp. 1211-1230 ◽  
Author(s):  
HYUN SANG CHO ◽  
TAKEKAZU KATO ◽  
TATSUYA YAMAZAKI ◽  
MINSOO HAHN

The home network is one of the emerging areas from the last century. However, the growth of the home network market is stationary at present. This paper describes the limitations of the home network system and the requirements for overcoming the current limitations. Also described is a new home network service system known as COWS and its easy installation and scalable operation. COWS consists of power consumption monitor and control devices along with a service server that is a complementary combination of Open Service Gateway initiative (OSGi) and web services. A home network system has a dynamic, heterogeneous, distributed, and scalable topology. Service Oriented Architecture (SOA) has been proposed as a solution that satisfies the requirement of a home network, and OSGi and web services are two successful SOA-based frameworks. An included service server has a flexible architecture that consists of a core and extendable service packages. A power consumption monitor and control function provides useful context information for activity-based context-aware services and optimizes the power consumption. The system can be installed easily into existing and new houses to solve the current barrier of the popularization of home network services.


Sign in / Sign up

Export Citation Format

Share Document