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Full-Text Articles in Social and Behavioral Sciences
Impact Of Wind Generation Mix On Transient Stability For An Interconnected Power System, Lasantha Meegahapola, Damian Flynn, Jason Kennedy, Tim Littler
Impact Of Wind Generation Mix On Transient Stability For An Interconnected Power System, Lasantha Meegahapola, Damian Flynn, Jason Kennedy, Tim Littler
Dr Lasantha G Meegahapola
The rapid growth of wind generation in many European countries is pushing power systems into uncharted territory. As additional wind generators are installed, the changing generation mix may impact on power system stability. This paper adopts the New England 39 bus system as a test system for transient stability analysis. Thermal generator models are based on a likely future plant mix for existing systems, while varying capacities of fixed-speed induction generators (FSIG) and doubly-fed induction generators (DFIG) are considered. The main emphasis here has been placed on the impact of wind technology mix on inter-area oscillations following transient grid disturbances. …
Characterisation Of Flicker Emission And Propagation In Distribution Networks With Bi-Directional Power Flows, D Perera, L Meegahapola, S Perera, P Ciufo
Characterisation Of Flicker Emission And Propagation In Distribution Networks With Bi-Directional Power Flows, D Perera, L Meegahapola, S Perera, P Ciufo
Dr Lasantha G Meegahapola
With the increasing penetration levels of intermittent and fluctuating energy sources such as wind generating systems in the electricity grid, resulting voltage fluctuations and flicker can be expected to become an important power quality considerations. Due to significant bidirectional power flows resulting from large renewable power generation systems connected to downstream, voltage fluctuations may propagate from downstream to upstream. The work presented in this paper investigates and characterises flicker emission and propagation resulting from fluctuating generating sources connected to a distribution network. Mathematical models are developed for flicker emission under different generator control strategies and flicker propagation to upstream network. …
Comparative Analysis Of Dynamic Line Rating Models And Feasibility To Minimise Energy Losses In Wind Rich Power Networks, Mathew Simms, Lasantha Meegahapola
Comparative Analysis Of Dynamic Line Rating Models And Feasibility To Minimise Energy Losses In Wind Rich Power Networks, Mathew Simms, Lasantha Meegahapola
Dr Lasantha G Meegahapola
Wind power generation has indicated an exponential increase during last two decades and existing transmission network infrastructure is increasingly becoming inadequate to transmit remotely generated wind power to load centres in the network. The dynamic line rating (DLR) is one of the viable solutions to improve the transmission line ampacity during high wind penetration without investing on an additional transmission network. The main objective of this study is to identify the basic differences between two main line rating standards, since transmission network service providers (TNSPs) heavily depend on these two standards when developing their line rating models. Therefore, a parameter …
Optimal Power Flow With Variable Wind Conditions, S Durairaj, L Meegahapola, D Flynn, B Fox
Optimal Power Flow With Variable Wind Conditions, S Durairaj, L Meegahapola, D Flynn, B Fox
Dr Lasantha G Meegahapola
This paper presents simulation studies of an electric arc furnace (EAF) model in the MATLAB/SIMULINK environment. EAF was modeled as a current source controlled by a non-linear resistance. Voltage flicker, a phenomenon of annoying light intensity fluctuation, caused by EAF, has been a major power quality concern for both power companies and customers. A model was developed for the electric arc furnace and it was applied in the simulation studies of distribution static synchronous compensator (DSTATCOM) for voltage flicker mitigation. The controller for DSTATCOM was designed based on DQ-model for the reactive power management which helps in the mitigation of …
Voltage And Power Quality Improvement Strategy For A Dfig Wind Farm During Variable Wind Conditions, L Meegahapola, T Littler, B Fox, J Kennedy, D Flynn
Voltage And Power Quality Improvement Strategy For A Dfig Wind Farm During Variable Wind Conditions, L Meegahapola, T Littler, B Fox, J Kennedy, D Flynn
Dr Lasantha G Meegahapola
This paper presents a voltage and power quality enhancement scheme for a doubly-fed induction generator (DFIG) wind farm during variable wind conditions. The wind profiles were derived considering the measured data at a DFIG wind farm located in Northern Ireland (NI). The aggregated DFIG wind farm model was validated using measured data at a wind farm during variable generation. The voltage control strategy was developed considering the X/R ratio of the wind farm feeder which connects the wind farm and the grid. The performance of the proposed strategy was evaluated for different X/R ratios, and wind profiles with different characteristics. …
Impact On Transient And Frequency Stability For A Power System At Very High Wind Penetration, Lasantha Meegahapola, Damian Flynn
Impact On Transient And Frequency Stability For A Power System At Very High Wind Penetration, Lasantha Meegahapola, Damian Flynn
Dr Lasantha G Meegahapola
This paper analyzes the impact on transient and frequency stability for a power system at very high wind penetration (40% wind). Wind penetration is based on the doubly-fed induction generator (DFIG), and a systematic approach has been adopted for wind power integration. A sensitivity analysis has been carried out for each wind integration scenario and for different wind generator loading conditions. A range of fault locations has been selected for stability analysis based on the proximity to synchronous generation and wind farms. The analysis has shown that transient stability performance is subject to fault location in the network, especially when …
Optimal Allocation Of Reactive Power Resources To Minimise Losses And Maintain System Security, Eknath Vittal, Lasantha Meegahapola, Damian Flynn, Andrew Keane
Optimal Allocation Of Reactive Power Resources To Minimise Losses And Maintain System Security, Eknath Vittal, Lasantha Meegahapola, Damian Flynn, Andrew Keane
Dr Lasantha G Meegahapola
Modern doubly-fed induction generator (DFIG) wind turbines have significant reactive power control capability, even during low wind speed conditions. This can improve system security by providing terminal voltage control at buses in the system. Generally, such control employs the full range of reactive power production from the turbine which can lead to increased system losses. By utilizing optimal power flow analysis, and limiting the range of reactive power production at certain wind farms, system losses can be minimized. If the reactive power of the wind farms are optimized to achieve the minimum system losses this may adversely affect the voltage …
Transient Stability Analysis Of A Power System With High Wind Penetration, Lasantha Meegahapola, Damian Flynn, Tim Littler
Transient Stability Analysis Of A Power System With High Wind Penetration, Lasantha Meegahapola, Damian Flynn, Tim Littler
Dr Lasantha G Meegahapola
This paper presents transient stability analysis for a power system with high wind penetration. The transient stability has been evaluated based on two stability criteria: rotor angle stability and voltage stability. A modified IEEE-14 bus system has been used as the main study network and simulations have been conducted at several wind power penetration levels, defined as a fraction of total system generation. A wide range of scenarios have been presented based on the wind farm voltage at the point of connection, i.e. low voltage (LV) distribution level and high voltage (HV) transmission level, and the type of wind generator …
Multi-Objective Reactive Power Support From Wind Farms For Network Performance Enhancement, Lasantha Meegahapola, Brendan Fox, Tim Littler, Damian Flynn
Multi-Objective Reactive Power Support From Wind Farms For Network Performance Enhancement, Lasantha Meegahapola, Brendan Fox, Tim Littler, Damian Flynn
Dr Lasantha G Meegahapola
This paper examines the ability of the doubly fed induction generator (DFIG) to deliver multiple reactive power objectives during variable wind conditions. The reactive power requirement is decomposed based on various control objectives (e.g. power factor control, voltage control, loss minimisation, and flicker mitigation) defined around different time frames (i.e. seconds, minutes, and hourly), and the control reference is generated by aggregating the individual reactive power requirement for each control strategy. A novel coordinated controller is implemented for the rotor-side converter and the grid-side converter considering their capability curves and illustrating that it can effectively utilise the aggregated DFIG reactive …
Voltage Security Constrained Reactive Power Optimization Incorporating Wind Generation, L G. Meegahapola, E Vittal, A Keane, D Flynn
Voltage Security Constrained Reactive Power Optimization Incorporating Wind Generation, L G. Meegahapola, E Vittal, A Keane, D Flynn
Dr Lasantha G Meegahapola
This paper presents a comparative analysis between conventional optimal power flow (OPF) and voltage constrained OPF strategies with wind generation. The study has been performed using the New England 39 bus system with 12 doublyfed induction generator (DFIG) based wind farms installed across the network. A voltage security assessment is carried out to determine the critical wind farms for voltage stability enhancement. The power losses and individual wind farm reactive power generation have been compared with and without voltage stability constraints imposed on the OPF simulation. It is shown that voltage constrained OPF leads to much greater active power losses …
Capability Curve Based Enhanced Reactive Power Control Strategy For Stability Enhancement And Network Voltage Management, Lasantha Meegahapola, Tim Littler, Sarath Perera
Capability Curve Based Enhanced Reactive Power Control Strategy For Stability Enhancement And Network Voltage Management, Lasantha Meegahapola, Tim Littler, Sarath Perera
Dr Lasantha G Meegahapola
Reactive power has become a vital resource in modern electricity networks due to increased penetration of distributed generation. This paper examines the extended reactive power capability of DFIGs to improve network stability and capability to manage network voltage profile during transient faults and dynamic operating conditions. A coordinated reactive power controller is designed by considering the reactive power capabilities of the rotor-side converter (RSC) and the grid-side converter (GSC) of the DFIG in order to maximise the reactive power support from DFIGs. The study has illustrated that, a significant reactive power contribution can be obtained from partially loaded DFIG wind …
Optimization Of Frt Active Power Performance Of A Dfig During Transient Grid Faults, L Meegahapola, Damian Flynn, Tim Littler
Optimization Of Frt Active Power Performance Of A Dfig During Transient Grid Faults, L Meegahapola, Damian Flynn, Tim Littler
Dr Lasantha G Meegahapola
Optimal fault ride-through (FRT) conditions for a doubly-fed induction generator (DFIG) during a transient grid fault are analyzed with special emphasis on improving the active power generation profile. The transition states due to crowbar activation during transient faults are investigated to exploit the maximum power during the fault and post-fault period. It has been identified that operating slip, severity of fault and crowbar resistance have a direct impact on the power capability of a DFIG, and crowbar resistance can be chosen to optimize the power capability. It has been further shown that an extended crowbar period can deliver enhanced inertial …
No Limits To Watching?, Katina Michael, M.G. Michael
No Limits To Watching?, Katina Michael, M.G. Michael
M. G. Michael
Little by little, the introduction of new body-worn technologies is transforming the way people interact with their environment and one another, and perhaps even with themselves. Social and environmental psychology studies of human-technology interaction pose as many questions as answers. We are learning as we go: 'learning by doing' through interaction and 'learning by being'. Steve Mann calls this practice existential learning; wearers become photoborgs, a type of cyborg (cybernetic organism) whose primary intent is image capture from the domains of the natural and artificial. This approach elides the distinction between the technology and the human; they coalesce into one.
No Limits To Watching?, Katina Michael, M.G. Michael
No Limits To Watching?, Katina Michael, M.G. Michael
Professor Katina Michael
Little by little, the introduction of new body-worn technologies is transforming the way people interact with their environment and one another, and perhaps even with themselves. Social and environmental psychology studies of human-technology interaction pose as many questions as answers. We are learning as we go: 'learning by doing' through interaction and 'learning by being'. Steve Mann calls this practice existential learning; wearers become photoborgs, a type of cyborg (cybernetic organism) whose primary intent is image capture from the domains of the natural and artificial. This approach elides the distinction between the technology and the human; they coalesce into one.
Agent-Based Demand Management In A Power Distribution Network By Considering Distributed Generations, Fenghui Ren, Minjie Zhang, Danny Soetanto
Agent-Based Demand Management In A Power Distribution Network By Considering Distributed Generations, Fenghui Ren, Minjie Zhang, Danny Soetanto
Dr Fenghui Ren
A distribution network carries electricity from transmission network to consumers through facilities such as substations, buses and feeders. Distributed generations emerge as the new alternative power resource to a distribution network at a smaller and distributed scale. On one hand, distributed generations can decrease substations' load and power price. On the other hand, they will bring difficulties to substations for demand management. This paper proposes a multiagent model to represent a radial distribution network. The model includes five types of agents, which are substation agents, bus agents, feeder agents, load agents and generation agents. Through communicating with neighbouring agents, each …
A Multiagent Approach For Decentralized Voltage Regulation In Power Distribution Networks Within Dgs, Fenghui Ren, Minjie Zhang, Danny Sutanto
A Multiagent Approach For Decentralized Voltage Regulation In Power Distribution Networks Within Dgs, Fenghui Ren, Minjie Zhang, Danny Sutanto
Dr Fenghui Ren
Voltage regulation (VR) is a procedure to keep voltages in a distribution network (DN) within normal limits. Conven- tionally, a voltage regulator can read voltage levels from pre- dened measures, and regulate the voltages. However, due to lacking of a distributed generator's (DG) information, the unexpected electricity from a DG will mislead readings on voltages levels, so as to disturb the VR in a DN. Adjust- ing a DG's reactive power output is an alternative way for VR. However, because of limited penetration levels, DGs need to collaborate with other devices in order to provide an eective voltage regulation. Therefore, …
The Affective Power Of Sound: Oral History On Radio, Siobhan A. Mchugh
The Affective Power Of Sound: Oral History On Radio, Siobhan A. Mchugh
Siobhan McHugh
Using illustrative audio clips, this article offers insights into the historical symbiosis between oral history and radio and the relationship between orality, aurality, and affect that makes radio such a powerful medium for the spoken word. It does so through a discussion of the concept of affect as it applies to oral history on radio and through a description and analysis of crafting oral history for the radio documentary form. This article features audio excerpts from radio documentaries produced by the author. Listening to the audio portions of this article requires a means of accessing the audio excerpts through hyperlinks. …
Hybrid Nanomembranes For High Power And High Energy Density Supercapacitors And Their Yarn Application, Jae Ah Lee, Min-Kyoon Shin, Seon Jeong Kim, Geoffrey Maxwell Spinks, Gordon G. Wallace, Raquel Ovalle-Robles, Marcio D. Lima, Mikhail E. Kozlov, Ray H. Baughman
Hybrid Nanomembranes For High Power And High Energy Density Supercapacitors And Their Yarn Application, Jae Ah Lee, Min-Kyoon Shin, Seon Jeong Kim, Geoffrey Maxwell Spinks, Gordon G. Wallace, Raquel Ovalle-Robles, Marcio D. Lima, Mikhail E. Kozlov, Ray H. Baughman
Gordon Wallace
Ultrathin (thicknessnm) electrically conducting membranes can be used as electrodes for sensors, actuators, optical devices, fuel cells, scaffolds for assembling nanoparticles, and separation of biological macromolecules.1-6 Various approaches have been suggested for the fabrication of free-standing nanomembranes based on organic polymers and/or inorganic materials: spin-casting of films,7 layer-by-layer assembly of polyelectrolyte multilayers,8 cross-linking of self-assembled monolayers,9 and assembly of triblock copolymers.10,11 Loading materials such as gold nanoparticles12 or carbon nanotubes13 make membranes robust and electrically conductive. However, these methods are often time-consuming and have some limitations in terms of achievable electrical and electrochemical membrane performance as well as scale-up. Alternative …
Power Of The Korean Film Producer: Dictator Park Chung Hee's Forgotten Film Cartel Of The 1960s Golden Decade And Its Legacy, Ae-Gyung Shim, Brian Yecies
Power Of The Korean Film Producer: Dictator Park Chung Hee's Forgotten Film Cartel Of The 1960s Golden Decade And Its Legacy, Ae-Gyung Shim, Brian Yecies
Dr Brian Yecies
After censorship was eliminated in 1996, a new breed of writer-directors created a canon of internationally provocative and visually stunning genre-bending hit films, and new and established producers infused unprecedented venture capital into the local industry. Today, a bevy of key producers, including vertically integrated Korean conglomerates, maintain dominance over the film industry while engaging in a variety of relatively near-transparent domestic and international expansion strategies. Backing hits at home as well as collaborating with filmmakers in China and Hollywood have become priorities. In stark contrast to the way in which the film business is conducted today is Korean cinema’s …
Power Of The Korean Film Producer: Dictator Park Chung Hee's Forgotten Film Cartel Of The 1960s Golden Decade And Its Legacy, Ae-Gyung Shim, Brian Yecies
Power Of The Korean Film Producer: Dictator Park Chung Hee's Forgotten Film Cartel Of The 1960s Golden Decade And Its Legacy, Ae-Gyung Shim, Brian Yecies
Dr Brian Yecies
After censorship was eliminated in 1996, a new breed of writer-directors created a canon of internationally provocative and visually stunning genre-bending hit films, and new and established producers infused unprecedented venture capital into the local industry. Today, a bevy of key producers, including vertically integrated Korean conglomerates, maintain dominance over the film industry while engaging in a variety of relatively near-transparent domestic and international expansion strategies. Backing hits at home as well as collaborating with filmmakers in China and Hollywood have become priorities. In stark contrast to the way in which the film business is conducted today is Korean cinema’s …
Maybe It’S Right, Maybe It’S Wrong: Structural And Social Determinants Of Deception In Negotiation, Mara Olekalns, Chris Horan, Philip Smith
Maybe It’S Right, Maybe It’S Wrong: Structural And Social Determinants Of Deception In Negotiation, Mara Olekalns, Chris Horan, Philip Smith
Mara Olekalns
Context shapes negotiators’ actions, including their willingness to act unethically. Focusing on negotiators use of deception, we used a simulated two-party negotiation to test how three contextual variables - regulatory focus, power, and trustworthiness - interacted to shift negotiators’ ethical thresholds. We demonstrated that these three variables interact to either inhibit or activate deception, providing support for an interactionist model of ethical decision-making. Three patterns emerged from our analyses. First, low power inhibited and high power activated deception. Second, promotion-focused negotiators favored sins of omission whereas prevention-focused negotiators favored sins of commission. Third, low cognition-based trust influenced deception when negotiators …
Maybe It’S Right, Maybe It’S Wrong: Structural And Social Determinants Of Deception In Negotiation, Mara Olekalns
Maybe It’S Right, Maybe It’S Wrong: Structural And Social Determinants Of Deception In Negotiation, Mara Olekalns
Mara Olekalns
Context shapes negotiators’ actions, including their willingness to act unethically. Focusing on negotiators use of deception, we used a simulated two-party negotiation to test how three contextual variables - regulatory focus, power, and trustworthiness - interacted to shift negotiators’ ethical thresholds. We demonstrated that these three variables interact to either inhibit or activate deception, providing support for an interactionist model of ethical decision-making. Three patterns emerged from our analyses. First, low power inhibited and high power activated deception. Second, promotion-focused negotiators favored sins of omission whereas prevention-focused negotiators favored sins of commission. Third, low cognition-based trust influenced deception when negotiators …