Publications
424 results found
Sokolov M, Green TC, Mitcheson PD, et al., 2010, Dynamic Analysis of Photovoltaic System withMPP Locus Emulation, 2010 IEEE 26-th Convention of Electrical and Electronics Engineers in Israel, Publisher: IEEE, Pages: 212-215
Bottrell N, Prodanović M, Green TC, 2010, Analysed small signal state-space model of an active rectifier
This paper presents a small signal state-space model of an active rectifier. The model considers the reference frame, the variation of frequency and control dynamics. It is suitable for analysing small signal stability of active rectifier loads in networks where a small load perturbation may cause a frequency disturbance. The model is formed by separating the active rectifier into sub sections. Each subsection is modelled independently before being consolidated into a single small signal state-space equation. A sensitivity analysis of the active rectifier is also presented which identifies the states most associated with each mode. This indicates possible feedback signals for the design of controllers to improve the system stability. The model is tested using rapid prototyping power converters configured as the active rectifier itself and the system load. The laboratory arrangement allows the active rectifier to be connected to either the public network via isolation transformers or a private network where the voltage and frequency are fully controllable. During the experimentation the active rectifier is shown to have negative impedance characteristics which are known to cause destabilising effects in networks.
Tan CW, Green TC, Hernandez-Aramburo CA, 2010, A stochastic method for battery sizing with uninterruptible-power and demand shift capabilities in PV (photovoltaic) systems, ENERGY, Vol: 35, Pages: 5082-5092, ISSN: 0360-5442
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- Citations: 45
Dinh MM, Roncal S, Green TC, et al., 2010, Trends in head injuries and helmet use in cyclists at an inner-city major trauma centre, 1991-2010, MEDICAL JOURNAL OF AUSTRALIA, Vol: 193, Pages: 619-620, ISSN: 0025-729X
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- Citations: 8
Merlin MMC, Green TC, Mitcheson PD, et al., 2010, A New Hybrid Multi-Level Voltage-Sourced Converter with DC Fault Blocking Capability, IET Conference on AC/DC Transmission
Rogers DJ, Green TC, 2010, Method And Apparatus For Performing On-Load Mechanical Switching Operations
An electrical device comprising: a first current path having a primary switch therein, and means for coupling to an electrical supply; and a diversionary current path having semiconductor switching means therein, the semiconductor switching means being operable to bypass the primary switch; the device being arranged such that, in use, a first current flowing from the supply along the first current path can be diverted, on the operation of the semiconductor switching means, along the diversionary current path, bypassing the primary switch; wherein the diversionary current path comprises a controllable electrical supply operable to supply a second current whilst the semiconductor switching means are in a state of conduction, the second current being such as to cause substantially zero current to flow through the primary switch, such that the primary switch can then be opened under a condition of substantially zero load current. A corresponding method of operating a mechanical switch in such a device is also provided.The disclosure further provides a controllable electrical supply comprising: an electrical source; an amplifier having two output terminals and comprising a plurality of semiconductor devices; and control logic arranged to operate the amplifier such that it can selectively present both current and voltage source behaviour at the terminals.
Rogers DJ, Green TC, 2010, Zero-current zero-voltage switching for on-load tap changers
We present a new on-load tap changer (OLTC) design that provides the traditional advantages of the semiconductor-assisted OLTC over the classic, mechanical OLTC. The design provides zero-current, zero-voltage operation of both diverter switches at all times, eliminating contact wear due to arcing. The design of the diverter sub-circuit is discussed, including the introduction of a voltage source and corresponding control loop that provides the necessary shunt current or voltage to create the desired zero conditions in the diverter switches. The design differs from existing semiconductor-assisted OLTC systems by the fact that the semiconductor portion of the system is connected in a purely shunt configuration to the main current path. Under normal conditions the load current flows only in the selector and diverter switches making the system very low loss.
Ahmadi AR, Green TC, 2010, Voltage versus Power Factor Regulation for enhancement of renewable generation capacity
The connection of Distributed Generators (DGs) to distribution network creates technical concerns for Distribution Network Operators (DNOs) which primarily include power flow management, loss increase and voltage management problems. Active Network Management (ANM) system provides monitoring and control of the distribution network as well as providing the infrastructure and technology for full integration of DGs to the distribution network. Optimal Power Flow (OPF) is a valuable tool in providing optimal control solutions for active network management system applications. In this paper, Terminal Voltage Regulator Mode (TVRM) and fixed Power Factor Regulation Mode (PFRM) were incorporated in the main optimisation routine to extract the maximum real power output capacity. The main contribution was to test different droop characteristics including one with local voltage regulator dead-bands associated to a particular DG. The DG operation methods of PFRM and TVRM are then compared together. Numerical result obtained from tests on two U.K. representative distribution networks show that TVRM has the potential in offering more capacity exploitation and improving network flexibility for additional DG connection.
Sudtharalingam S, Hawkes AD, Green TC, 2010, Energy Policies for Domestic Micro Combined Heat and Power in the UK: A Comparison, 8th Young Energy Engineers &. Economists Seminar (YEEES)
Acha S, Green TC, Shah N, 2010, Techno-economical Tradeoffs from Embedded Technologies with Storage Capabilities on Electric and Gas Distribution Networks, IEEE-Power-and-Energy-Society General Meeting, Publisher: IEEE, ISSN: 1944-9925
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- Citations: 2
Rogers DJ, Divan DM, Green TC, 2010, Modelling and Optimal Switching Pattern Generation for AC to AC Power Converters, IEEE-Power-and-Energy-Society General Meeting, Publisher: IEEE, ISSN: 1944-9925
Rogers DJ, Green TC, 2010, A Hybrid Diverter Design for Distribution Level On-load Tap Changers, IEEE Energy Conversion Congress and Exposition (ECCE), Publisher: IEEE, Pages: 1493-1500, ISSN: 2329-3721
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- Citations: 7
Plet CA, Graovac M, Green TC, et al., 2010, Fault Response of Grid-Connected Inverter Dominated Networks, IEEE-Power-and-Energy-Society General Meeting, Publisher: IEEE, ISSN: 1944-9925
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- Citations: 35
Acha S, Green TC, Shah N, 2010, Effects of Optimised Plug-in Hybrid Vehicle Charging Strategies on Electric Distribution Network Losses, 2010 IEEE PES Transmission and Distribution Conference and Exposition - Smart Solutions for a Changing World, Publisher: IEEE
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- Citations: 1
Clemow P, Green TC, Hernandez-Aramburo CA, 2010, Wind Farm Output Smoothing Through Co-ordinated Control and Short-term Wind Speed Prediction, IEEE-Power-and-Energy-Society General Meeting, Publisher: IEEE, ISSN: 1944-9925
Bloemink JM, Green TC, 2010, Increasing Distributed Generation Penetration using Soft Normally-Open Points, IEEE-Power-and-Energy-Society General Meeting, Publisher: IEEE, ISSN: 1944-9925
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- Citations: 69
Taylor PC, Xu T, Wade NS, et al., 2010, Distributed Voltage Control in AuRA-NMS, IEEE-Power-and-Energy-Society General Meeting, Publisher: IEEE, ISSN: 1944-9925
Kondala Rao G, Mitcheson PD, Green TC, 2009, Mixed Electromechanical Simulation of Electrostatic Microgenerator Using Custom-Semiconductor Device Models, PowerMEMS 2009, Pages: 356-359, ISSN: 2151-3155
Green T, 2009, AuRA-NMS: A substation automation project for a potential smart grid
The smartGrid concept envisages a much more actively controlled distribution network with high asset utilisation and many active elements such as distributed generation, storage and responsive demand. One way of handling the increased control and communication complexity is to decentralise control and place autonomous controllers in substations that have authority to manage tap-changers and generator constraints so as to increase DG capacity while respecting network limits. Such controllers can also perform feeder-level restoration based on local measurement. Such controllers can be gradually introduced as SmartGrid regions within existing networks. The Aura-NMS project is a collaboration of eight UK universities, two network operators and a manufacturer to develop and test these ideas.
Domahidi A, Chaudhuri B, Korba P, et al., 2009, Self-tuning flexible ac transmission system controllers for power oscillation damping: A case study in real time, IET Generation, Transmission & Distribution, Vol: 3, Pages: 1079-1089
Xu T, Taylor P, Prodanovic M, et al., 2009, Case based reasoning for distributed voltage control
Distribution networks were not designed with significant levels of Distributed Generation (DG) in mind, therefore the proliferation of DG results in a number of technical challenges. Controlling network voltages, while also providing adequate DG access, represents one of the most important challenges. This paper presents research being carried out, as part of the UK AuRA -NMS research project, to address this challenge through the novel application of novel case based reasoning.
Acha S, Green TC, Shah N, 2009, Impacts of plug-in hybrid vehicles and combined heat and power technologies on electric and gas distribution network losses, 2009 IEEE PES/IAS Conference on Sustainable Alternative Energy (SAE), Publisher: IEEE, Pages: 1-7
Distribution network operators (DNOs) require strategies that can offset the tradeoffs new embedded technologies have on their assets. This paper employs modelling to show that through control device manipulation, gas and electric (G&E) network operators can influence savings in energy losses under the presence of plug-in hybrid vehicles (PHEVs) and combined heat and power technologies (CHPs). An integrated gas and electric optimal power flow (OPF) tool is introduced to undertake various case studies. The OPF tool evaluates the technical impacts experienced in the networks when DNOs apply a "plug and forget" operation strategy and then compares the results against a "loss minimisation" strategy. Results show the benefits in applying different strategies are more considerable in electric networks than in gas networks. The study corroborates that an integrated G&E analysis offers a fresh perspective for stakeholders in evaluating energy service networks performance under different operation strategies.
Liang J, Green TC, Feng C, et al., 2009, Increasing Voltage Utilization in Split-Link, Four-Wire Inverters, IEEE TRANSACTIONS ON POWER ELECTRONICS, Vol: 24, Pages: 1562-1569, ISSN: 0885-8993
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- Citations: 64
Ahmadi AR, Green TC, 2009, Optimal Power Flow for Autonomous Regional Active Network Management System, General Meeting of the IEEE-Power-and-Energy-Society, Publisher: IEEE, Pages: 4536-4542, ISSN: 1944-9925
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- Citations: 3
Walton C, Green T, Woods T, 2008, Supergen futurenet and flexnet
The paper outlines the work and conclusions of the four year Supergen FutureNet consortium of eight UK universities and many industrial sponsors that concluded in summer 2007. It then sets out the research program and objectives of the follow-on four year £7m FlexNet consortium and its implications for Smart Grids.
Xu Z, Green T, 2008, A Singular Value Decomposition Approach to Similarity Evaluation Between Servo Loops of CNC Machine Tools, ASME International Mechanical Engineering Congress and Exposition, Publisher: ASME, ISSN: 1087-1357
Barklund E, Pogaku N, Prodanovic M, et al., 2008, Energy Management in Autonomous Microgrid Using Stability-Constrained Droop Control of Inverters, IEEE TRANSACTIONS ON POWER ELECTRONICS, Vol: 23, Pages: 2346-2352, ISSN: 0885-8993
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- Citations: 553
Mitcheson PD, Yeatman EM, Rao GK, et al., 2008, Energy Harvesting From Human and Machine Motion for Wireless Electronic Devices, Proceedings of the IEEE, Vol: 96, Pages: 1457-1486
Skea J, Anderson D, Green T, et al., 2008, Intermittent renewable generation and maintaining power system reliability, Generation, Transmission & Distribution, Vol: 2, Pages: 82-89, ISSN: 1751-8687
There have been attempts, using various approaches, to assess the additional cost of running an electricity system when intermittent renewable generation is used to provide a significant proportion of the energy. The key issues are the difference, in statistical terms, between the resource availability of the intermittent source and conventional generation and the contribution the intermittent source can make to meet the system peak demand while maintaining system reliability. There is considerable agreement over the capacity credits that can be attributed to renewable energy sources, that is the amount of conventional capacity that renewables can reliablydisplace, yet the implications for costs have proved more controversial. Approaches to calculate changes in overall system cost are examined and an expression for the additional cost that intermittent generation imposes on a system that is attributable to its intermittent nature is identified. Further, it is shown that this expression can be reconciled with approaches that look at intermittent renewables on a stand-alone basis and factor in the additional costs of ‘standby’ capacity. It is shown that the main source of divergence between estimates of the cost of intermittency is the load factor implicitly assumed for the conventional plant used as a reference. There is only one consistent way to impute the costs of intermittency when the unit cost of intermittent plant is being compared with that of baseload generation plant.
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