Negotiating agents play a key role in e-markets and become more popular. However, in much existin... more Negotiating agents play a key role in e-markets and become more popular. However, in much existing work, the e-markets are assumed to be closed and static, which is unrealistic. To address the issue, this paper developed negotiating agents that can adapt their negotiation strategies, outcome expectations, offer evaluations, and counter-offers generations in dynamic, open e-markets. Also, the proposed agents can generate multiple counter-offers according to different preferences so as to further improve their negotiation outcomes. Finally, the experimental results show the improvements on agents' profits by employing our negotiation model.
A distribution network carries electricity from transmission network to consumers through facilit... more 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 agent can dynamically balance its own power supply and consumption, so as to perform the demand management to the distribution network. The Java Agent Development Framework (JADE) was employed to implement the proposed agents and multiagent system. The simulation result on a case study well demonstrates the good design and performance of the proposed multiagent system in both agents communication and demand management.
Design of an Intelligent Self-Healing Smart Grid using a Hybrid Multi-Agent Framework
Journal of Electronic Science and Technology, 2011
This paper discusses the applications of a hybrid multi-agent framework for self-healing applicat... more This paper discusses the applications of a hybrid multi-agent framework for self-healing applications in an intelligent smart grid system following catastrophic disturbances such as loss of generators or during system fault. The proposed hybrid multi-agent framework is a hybrid of both centralized and decentralized scheme to allow distributed intelligent agent in the smart grid system to make fast local decision while allowing the slower central controller to judge the effectiveness of the decision made by the local agents and to suggest more optimal solutions.
The International Journal of Electrical Engineering & Education, 1994
An interactive computer-aided package for electrical engineering education This paper describes a... more An interactive computer-aided package for electrical engineering education This paper describes an interactive, general-purpose computer-aided teaching package. This package is for use on IBM or compatible personal computers. Although it was initially developed for training electrical engineering students, it is envisaged that it can also be applied to other areas of higher education.
Calculation of the leakage inductance of high frequency transformers with low permeability magnetic materials and superconductor windings for DC/DC converters
Transient Simulation of Capacitively Self-Excited Induction Motors
The paper examines the transient behaviour of a three-phase induction generator supplying a three... more The paper examines the transient behaviour of a three-phase induction generator supplying a three-phase symmetrical load. The effect of the magnetic saturation is firstly analysed using a generalised root locus approach from which an algorithm to represent saturation effect is derived and incorporated into a generalised machine model of an induction machine. The transient behaviour of the induction generator will be examined for various combination of load impedances and excitation capacitors. Comparison between the simulation results and test and experimental test data for a squirrel cage rotor and a wound rotor induction motor shows good agreement.
Outages and faults in interconnected power systems may cause cascading sequences of events, and c... more Outages and faults in interconnected power systems may cause cascading sequences of events, and catastrophic failures of power systems. How to efficiently manage power systems and restore the systems from faults is a challenging research issue in power engineering. Multi-agent systems are employed to address such a challenge in recent years. A centralized coordination strategy was firstly introduced to manage agents in a power system. Such a strategy usually adopts a single central coordinator to control the whole system for system management, maintenance, and restoration purposes. However, disadvantages such as deficiencies in robustness, openness, and flexibility prevent this strategy from extensive online applications. Consequently, a decentralized coordination strategy was proposed to overcome such limitations. But the decentralized coordination strategy cannot efficiently provide a global solution when serious faults spread out in a power system. In this paper, a conceptual multi-agent system design is introduced to express our proposal in power system modeling. A novel dynamic team forming mechanism is proposed to dynamically manage agents in power system with a flexible coordination structure, so as to balance the effectiveness and efficiency of the introduced multi-agent system. The results from simulations of case studies indicate the performance of the proposed multi-agent model.
Harmonic monitoring has become an important tool for harmonic management in distribution systems.... more Harmonic monitoring has become an important tool for harmonic management in distribution systems. A comprehensive harmonic monitoring program has been designed and implemented on a typical electrical MV distribution system in Australia. The monitoring program involved measurements of the three-phase harmonic currents and voltages from the residential, commercial and industrial load sectors. Data over a three year period has been downloaded and available for analysis. The large amount of acquired data makes it difficult to identify operational events that impact significantly on the harmonics generated on the system. More sophisticated analysis methods are required to automatically determine which part of the measurement data are of importance. Based on this information, a closer inspection of smaller data sets can then be carried out to determine the reasons for its detection. In this paper we classify the measurement data using data mining based on clustering techniques which can provide the engineers with a rapid, visually oriented method of evaluating the underlying operational information contained within the clusters. The paper shows how clustering can be used to identify interesting patterns of harmonic measurement data and how these relate to their associated operational issues.
The Hilbert Huang Transform (HHT) is a powerful tool for Power Quality (PQ) classifications. One ... more The Hilbert Huang Transform (HHT) is a powerful tool for Power Quality (PQ) classifications. One of the main advantages of the HHT is its ability to analyse non-stationary complex waveforms with very good time resolution. However, like other waveform classification techniques, it has difficulty in resolving the instant of sudden changes in the waveform. It has also difficulty with signals that have frequency components close together. This paper summarises the fundamentals of the HHT technique and its application to power quality classifications including its advantages and disadvantages. Two novel techniques to improve the performance of the HHT technique in analysing power quality problems will be proposed. Results from simulations will be provided and discussed.
International Journal of Electrical Power & Energy Systems, Feb 1, 1991
Variance, in addition to the expected production cost and loss of load probability, can be a very... more Variance, in addition to the expected production cost and loss of load probability, can be a very useful index in production costing, especially in the context q[power plant fuel management. Based on the load duration curve (LDC) and equivalent unit concepts, an efficient algorithm has been developed to evaluate the variances in both the system production cost as well as Jbr each generating unit. The approach is dflferent j?om previous work by Mazumdar and Yin, since it does not assume the LDC to be a probabilio'.function. It treats the LDC as a deterministic [unction of the load's duration time. Whih" the algorithm uses the LDC, it does not depend on it. The algorithm can he easily extended to chronological loads when used together with the Z-trans/brm method developed hi' Sutanto. Because the LDC is not assumed to he a probability jimetion here, this approach does not overestimate the variances as do methods that interpret the LDC as a probahili O' Junction 01 the load.
A Z-transform model of transformers for the study of electromagnetic transients in power systems
IEEE Transactions on Power Systems, 1990
A Z-transform model, which combines transformer frequency-dependent short-circuit impedances with... more A Z-transform model, which combines transformer frequency-dependent short-circuit impedances with gain functions, has been developed. It sets up a relationship between transient voltages and currents on both sides of a transformer winding pair. The model can be used to calculate impulse responses of the transformers with open-circuit secondary winding as well as those connected to other networks. It could be
The Hilbert Huang transform for decomposition of power quality waveforms
This paper describes the use of HHT to decompose power quality (PQ) signals with good resolution.... more This paper describes the use of HHT to decompose power quality (PQ) signals with good resolution. A brief description of why the method is needed and the operation of the method are presented. The advantages and disadvantages of HHT when applied to decompose stationary and non-stationary PQ signals are discussed.
A review of new innovations in power system control
Proceedings of 1995 International Conference on Power Electronics and Drive Systems. PEDS 95, 1995
Financial and environmental constraints have afflicted power systems throughout the world. Enviro... more Financial and environmental constraints have afflicted power systems throughout the world. Environmental pressures have forced the retirement and nonreplacement of power station close to urban load centres as well as making it more difficult and expensive to establish additional transmission lines to supply these large load centres. All these factors have altered the method of power system operation from the
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Papers by Danny Sutanto