Static output feedback frequency stabilization of time-delay power systems with coordinated electric vehicles state of charge control

In this paper, for the first time, electric vehicles are used for both the primary and secondary frequency controls to support power plants to rapidly suppress fluctuations in the system frequency due to load disturbances. Via networked control and wide-area communication infrastructures, multiple interval time-varying delays exist in the communication channels between the control center, power plant, and an aggregation of electric vehicles. By coordinating batteries’ state of charge control, the behaviors of the vehicle owners and the uncertainties imposed by the changes of the batteries’ state of charge are taken intoconsideration. A power system model incorporating multiple time-varying delays and uncertainties is first proposed. Then, a robust static output feedback frequency controller is designed to guarantee the resulting closed-loop system stable with an H∞ attenuation level. By utilizing a novel integral inequality, namely refined-Jensen inequality, and an improved reciprocally convex combination, the design conditions are formulated in terms of tractable linear matrix inequalities which can be efficiently solved by various computational tools. The effectiveness of the proposed control scheme is verified by extensive simulations.

Local total and radiative heat-transfer coefficients during the heat treatment of a workpiece in a fluidised bed

The heat-transfer coefficients around a workpiece immersed in an electrically heated heat treatment fluidised bed were studied. A suspension probe designed to simulate a workpiece of complex geometry was developed to measure local total and radiative heat-transfer coefficients at a high bed temperature. The probe consisted of an energy-storage region separated by insulation from the fluidised bed, except for the measuring surface, and a multi-thermocouple measurement system. Experiments in the fluidised bed were performed for a fluidising medium of 120-mesh alumina, a wide temperature range of 110–1050 °C and a fluidising number range of 1.18–4.24. It was found that the workpiece surface temperature has a more significant effect on heat transfer than the bed temperature. The total heat-transfer coefficient at the upper surface of the workpiece sharply decreased at the start of heating, and then steadily increased as heating progressed, while a sharp decrease became a rapid increase and then a slow increase for the radiative heat-transfer coefficient. A great difference in the heat-transfer coefficients around the workpiece was observed.

Emission-based condition monitoring technique for ZnO surge arrester

In this paper, electromagnetic emission at the frequency range of 30MHz to 300MHz is used to detect physical defects on the 22kV outdoor zinc-oxide (ZnO) surge arresters. Different weather conditions combining with artificially created pollution were produced in a laboratory environment and measurements were recorded over a fixed period of time. Pollution due to fine dust particles has been created according to IEC standard under both wet and dry conditions. The aim is to detect the defects (bushing damage) when the surge arrester is subjected to various weather and surface condition. The collected electromagnetic signals were sampled and analyzed using analysis tools such as the autocorrelation coefficient and Wigner-Ville distribution. The results from the present paper indicate that electromagnetic radiation from the defects on surge arrester combining with the adequate analysis tools can be used as a valuable diagnostic tool for power system operator.

Determination of structurally constrained controllors

This paper reports on determination of structurally constrained controllers for linear uncertain time-invariant systems from state controllers. It is shown that practical structures such as output and decentralized controllers may be derived from state feedback controllers. A previously studied load frequency control of a two-area interconnected power system is considered to illustrate the proposed approach.

Improving outcomes-based engineering education in Australia

Graduate attributes are now a ubiquitous feature of higher education in Australia and internationally, and have been part of engineering education for more than a decade. The idea of graduate attributes is an apparently simple concept, focusing on educational outcomes, rather than inputs and process. While there is evidence of some benefits in engineering education arising from the introduction of outcomes-based accreditation, there is also evidence of many short-comings of the graduate attributes approach. There would be significant value in Engineers Australia providing additional discipline-specific guidance on attribute development. There would be significant value in Engineers Australia simplifying and consolidating the current multi-document accreditation system. A genuinely outcomes-based accreditation system would be based (only) on the demonstrated individual student attainment of appropriate graduate attributes, which might be delivered/gained by a range of means, including distance education. To fully meet the letter and spirit of the law for accreditation, programs will need to adopt some method of certification of individual student attainment of graduate attributes - one such method would be the use of student portfolios.

Volume confinement induced microstructural transitions and property enhancements of supramolecular soft materials

The rheological properties of supramolecular soft functional materials are determined by the networks within the materials. This research reveals for the first time that the volume confinement during the formation of supramolecular soft functional materials will exert a significant impact on the rheological properties of the materials. A class of small molecular organogels formed by the gelation of N-lauroyl-L-glutamic acid din-butylamide (GP-1) in ethylene glycol (EG) and propylene glycol (PG) solutions were adopted as model systems for this study. It follows that within a confined space, the elasticity of the gel can be enhanced more than 15 times compared with those under un-restricted conditions. According to our optical microscopy observations and rheological measurements, this drastic enhancement is caused by the structural transition from a multi-domain network system to a single network system once the average size of the fiber network of a given material reaches the lowest dimension of the system. The understanding acquired from this work will provide a novel strategy to manipulate the network structure of soft materials, and exert a direct impact on the micro-engineering of such supramolecular materials in micro and nano scales.

An interview with Archie Weller

Interviews writer Archie Weller about Australian literature. Assessment of the value of his own work; View on criticism of Aboriginal writing; Weller's efforts to depict the plight of Nyoongahs in the white power system; Stature of black Australian writers; Comments on literary style; Shift in focus and emphasis in writing.

Planning with events and states

We present an overall planning system in which specifications can be described in terms of events and states. The underlying feature of this system is temporal logic, and its expressive power alloys one to deal with simultaneous actions and interacting actions. Moreover, one can represent both goal-oriented positive constraints and prevention-oriented negative constraints. The planning system can generate hierarchical plans and the overall model is capable of handling interacting agents.

Smart grid

All over the world, electrical power systems are encountering radical change stimulated by the urgent need to decarbonize electricity supply, to swap aging resources and to make effective application of swiftly evolving information and communication technologies (ICTs). All of these goals converge toward one direction; ‘Smart Grid.’ The Smart Grid can be described as the transparent, seamless, and instantaneous two-way delivery of energy information, enabling the electricity industry to better manage energy delivery and transmission and empowering consumers to have more control over energy decisions. Basically, the vision of Smart Grid is to provide much better visibility to lower-voltage networks as well as to permit the involvement of consumers in the function of the power system, mostly through smart meters and Smart Homes. A Smart Grid incorporates the features of advanced ICTs to convey real-time information and facilitate the almost instantaneous stability of supply and demand on the electrical grid. The operational data collected by Smart Grid and its sub-systems will allow system operators to quickly recognize the best line of attack to protect against attacks, susceptibility, and so on, sourced by a variety of incidents. However, Smart Grid initially depends upon knowing and researching key performance components and developing the proper education program to equip current and future workforce with the knowledge and skills for exploitation of this greatly advanced system. The aim of this chapter is to provide a basic discussion of the Smart Grid concept, evolution and components of Smart Grid, environmental impacts of Smart Grid and then in some detail, to describe the technologies that are required for its realization. Even though the Smart Grid concept is not yet fully defined, the chapter will be helpful in describing the key enabling technologies and thus allowing the reader to play a part in the debate over the future of the Smart Grid. The chapter concludes with the experimental description and results of developing a hybrid prediction method for solar power which is applicable to successfully implement the ‘Smart Grid.’

Impacts of DG penetration in the Bamaga and Gununa isolated distribution networks

Isolated distribution systems are dispersed throughout regional Queensland to supply small isolated communities that are distant from the main supply grid. The costs of maintaining the electricity supply to these areas is costly; mainly due to the cost of diesel fuel. Furthermore, there is a community focus on climate change, and Ergon Energy aims to reduce the reliance on fossil fuels whilst optimising cost efficiencies and greenhouse gas emissions. The objective of this study is to examine the impacts of renewable energy sources in isolated power systems. For the locations studied, viable renewable energy sources have been integrated into these networks. Anticipated challenges and issues with the integration of the intermittent renewable energy sources were addressed, using mitigation techniques, including energy storage solutions. The investigation and findings demonstrated that network improvements can be achieved by an ideal level of renewable penetration, which has been the main focus of the project. The project involved the development and simulation of MATLAB Simulink and SINCAL models of the two isolated networks at Gununa and Bamaga. The subsequent analysis of these systems has shown a modest penetration level of renewables can be combined with energy storage solutions, which reduces fuel consumption and greenhouse gas emissions at these locations.

Prospect of renewable energy sources and integrating challenges in Victoria, Australia

The Australian Government has targeted 20% of electricity generation from renewable energy sources by 2020. The 20% renewable energy target (RET) for Australia will be around 45000GWH in 2020. Renewable energy of Victoria also includes as part of support to achieve 20% RET in Australia. In Victoria wind and solar resources are abundant as compared to other sources of renewable energy. Solar radiation and wind speed data for Victoria State was collected from NASA surface meteorology and solar energy web site. A feasibility analysis has been carried out to explore the potentialities of wind and solar energy for Victoria State using hybrid optimization model of electric renewable (HOMER) software. This paper also represents the estimation analysis of RET for Victoria and describes the integrating challenges of renewable energy sources to the utility grid.

Fault detection for dynamical systems using first-order functional observers

This paper reports a new result on the fault detection of dynamical systems by employing only first-order functional observers. Indeed, we show that fault detection can be achieved by utilizing first-order functional observers. The advantages for having such simple structured observers are obvious from the economical and practical points of view as significant cost saving can be achieved. We derive existence conditions and an algorithm for the generation of residual signals to detect faults using firstorder functional observers. Two numerical examples are given to illustrate the proposed fault detection scheme. In one of the examples, a two-area interconnected power system with reheat thermal turbines is considered where only a first-order functional observer is designed to detect faults in the power system.

Influences of wind energy integration into the distribution network

Wind energy is one of the most promising renewable energy sources due to its availability and climate-friendly attributes. Large-scale integration of wind energy sources creates potential technical challenges due to the intermittent nature that needs to be investigated and mitigated as part of developing a sustainable power system for the future. Therefore, this study developed simulation models to investigate the potential challenges, in particular voltage fluctuations, zone substation, and distribution transformer loading, power flow characteristics, and harmonic emissions with the integration of wind energy into both the high voltage (HV) and low voltage (LV) distribution network (DN). From model analysis, it has been clearly indicated that influences of these problems increase with the increased integration of wind energy into both the high voltage and low voltage distribution network, however, the level of adverse impacts is higher in the LV DN compared to the HV DN.

Potentialities of renewable energy in Victoria, Australia

In utility power system, electricity demand is being covered largely by fossil fueled power generation, which contributes high level of GHG (greenhouse gas) emission and causes global warming worldwide. In order to reduce GHG emission level, most of the countries in the world targeting towards green energy that is power generation from RE (renewable energy) sources. In this paper, it is considered to study prospects of RE sources in particular, solar and wind in Victoria State which are abundant as compared to other sources of renewable. The wind and solar energy feasibility study and sensitivity analysis has been done for Victoria with the aid of HOMER (hybrid optimization model of electric renewable) simulation software. From the study, it has clearly evicted that wind energy combinational HPS (hybrid power system) has more contribution, and high potential than solar PV (photovoltaic) systems for a particular location. This study also investigates the influences of energy storage in the proposed HPS.

Experimental and simulation study of the impact of increased photovoltaic integration with the grid

The abundance, availability, and climate-friendly characteristics of solar photovoltaic (PV) energy encourage nations around the globe to adopt it to assist in overcoming global warming as well as build a sustainable society for the future. The intermittent nature of solar energy generation and the associated power electronic inverters with connected consumer loads creates a number of potential challenges in integrating large-scale PV into the grid that affects power quality of the distribution networks. This paper investigates the impacts of varying PV integration into the grid through experimental and simulation studies. Initially, several experiments were conducted with varying PV penetration and load conditions using the Renewable Energy Integration Facility at CSIRO, Newcastle, Australia. Later, a simulation model was developed that mimics the experimental facility used at CSIRO to investigate the adverse impacts on integrating large-scale PV into the grid using the power system simulation software PSS Sincal. Experimental and simulation analyses clearly indicate that integration of PV into the grid causes power quality issues such as voltage instability, harmonic injection, and low power factor into the networks and the level of these impacts increases with the increase of PV penetration. © 2014 AIP Publishing LLC.