Fault detection of wind turbine drivetrain utilizing power-speed characteristics

Wind energy, being the fastest growing renewable energy source in the present world, requires a large number of wind turbines to transform wind energy into electricity. One factor driving the cost of this energy is the reliable operation of these turbines. Therefore, it is a growing requirement within the wind farm community, to monitor the operation of the wind turbines on a continuous basis so that a possible fault can be detected ahead of time. As the wind turbine operates in an environment of constantly changing wind speed, it is a challenging task to design a fault detection technique which can accommodate the stochastic operational behavior of the turbines. Addressing this issue, this paper proposes a novel fault detection criterion which is robust against operational uncertainty, as well as having the ability to quantify severity level specifically of the drivetrain abnormality within an operating wind turbine. A benchmark model of wind turbine has been utilized to simulate drivetrain fault condition and effectiveness of the proposed technique has been tested accordingly. From the simulation result it can be concluded that the proposed criterion exhibits consistent performance for drivetrain faults for varying wind speed and has linear relationship with the fault severity level.

Sectionalizing strategies for minimizing outage durations of critical loads in parallel power system restoration with bi-level programming

Fast restoration of critical loads and non-black-start generators can significantly reduce the economic losses caused by power system blackouts. In a parallel power system restoration scenario, the sectionalization of restoration subsystems plays a very important role in determining the pickup of critical loads before synchronization. Most existing research mainly focuses on the startup of non-black-start generators. The restoration of critical loads, especially the loads with cold load characteristics, has not yet been addressed in optimizing the subsystem divisions. As a result, sectionalized restoration subsystems cannot achieve the best coordination between the pickup of loads and the ramping of generators. In order to generate sectionalizing strategies considering the pickup of critical loads in parallel power system restoration scenarios, an optimization model considering power system constraints, the characteristics of the cold load pickup and the features of generator startup is proposed in this paper. A bi-level programming approach is employed to solve the proposed sectionalizing model. In the upper level the optimal sectionalizing problem for the restoration subsystems is addressed, while in the lower level the objective is to minimize the outage durations of critical loads. The proposed sectionalizing model has been validated by the New-England 39-bus system and the IEEE 118-bus system. Further comparisons with some existing methods are carried out as well.

Nigeria's power sector: Analysis of productivity

Nigerian electricity market is characterized by inadequate electricity generation framework, compounded by lack of timely routine maintenances. This results in significant deterioration in plant electricity output. This study analyzes the productivity changes in the Nigerian power sector. Productivity increased on average in the power sector by the adoption of new technologies from best-practice power plants. The assumption of Hicks neutral technological change is found not to be suitable for the Nigerian power sector. This study finds that the plants are not using their capacity meaningfully, instead, there is a tendency to use labor.

Not learning from the past: Adaptive governance challenges for Australian natural resource management

Australia’s governance arrangements for NRM have evolved considerably over the last thirty years. The impact of changes in governance on NRM planning and delivery requires assessment. We undertake a multi-method program evaluation using adaptive governance principles as an analytical frame and apply this to Queensland to assess the impacts of governance change on NRM planning and governance outcomes. Data to inform our analysis includes: 1) a systematic review of sixteen audits/evaluations of Australian NRM over a fifteen-year period; 2) a review of Queensland’s first generation NRM Plans; and 3) outputs from a Queensland workshop on NRM planning. NRM has progressed from a bottom-up grassroots movement into a collaborative regional NRM model that has been centralised by the Australian Government. We found that while some adaptive governance challenges have been addressed, others remained unresolved. Results show that collaboration and elements of multi-level governance under the regional model were positive moves, but also that NRM arrangements contained structural deficiencies across multiple governance levels in relation to public involvement in decision-making and knowledge production for problem responsiveness. These problems for adaptive governance have been exacerbated since 2008. We conclude that the adaptive governance framework for NRM needs urgent attention so that important environmental management problems can be addressed.

Retaining a diverse workforce: The impact of gender-focused human resource management

Demography theory suggests that high gender diversity leads to high turnover. As turnover is costly, we tested the following: a main effect prediction derived from demography theory, and a moderating effect prediction derived from the relational framework. Data on 198 publicly listed organizations were collected through a human resources decision maker survey and archival databases. The results indicate that higher gender diversity leads to lower turnover in organizations with many gender-focused policies and practices. Findings suggest that organizations can lower their turnover rates by increasing their gender diversity and by implementing gender-focused policies and practices.

Comparison of charged nanoparticle concentrations near busy roads and overhead high-voltage power lines

Overhead high-voltage power lines are known sources of corona ions. These ions rapidly attach to aerosols to form charged particles in the environment. Although the effect of ions and charged particles on human health is largely unknown, much attention has focused on the increasing exposure as a result of the expanding power network in urban residential areas. However, it is not widely known that a large number of charged particles in urban environments originate from motor vehicle emissions. In this study, for the first time, we compare the concentrations of charged nanoparticles near busy roads and overhead power lines. We show that large concentrations of both positive and negative charged nanoparticles are present near busy roadways and that these concentrations commonly exceed those under high-voltage power lines. We estimate that the concentration of charged nanoparticles found near two freeways carrying around 120 vehicles per minute exceeded the corresponding maximum concentrations under two corona-emitting overhead power lines by as much as a factor of 5. The difference was most pronounced when a significant fraction of traffic consisted of heavy-duty diesel vehicles which typically have high particle and charge emission rates.

Robust design and optimisation of a radial turbine within a supercritical CO2 solar Brayton Cycle

The generation of solar thermal power is dependent upon the amount of sunlight exposure,as influenced by the day-night cycle and seasonal variations. In this paper, robust optimisation is applied to the design of a power block and turbine, which is generating 30 MWe from a concentrated solar resource of 560oC. The robust approach is important to attain a high average performance (minimum efficiency change) over the expected operating ranges of temperature, speed and mass flow. The final objective function combines the turbine performance and efficiency weighted by the off-design performance. The resulting robust optimisation methodology as presented in the paper gives further information that greatly aids in the design of non-classical power blocks through considering off-design conditions and resultant performance.

A LIN inspired optical bus for signal isolation in multilevel or modular power electronic converters

Proposed in this paper is a low-cost, half-duplex optical communication bus for control signal isolation in modular or multilevel power electronic converters. The concept is inspired by the Local Interconnect Network (LIN) serial network protocol as used in the automotive industry. The proposed communications bus utilises readily available optical transceivers and is suitable for use with low-cost microcontrollers for distributed control of multilevel converters. As a signal isolation concept, the proposed optical bus enables very high cell count modular multilevel cascaded converters (MMCCs) for high-bandwidth, high-voltage and high-power applications. Prototype hardware is developed and the optical bus concept is validated experimentally in a 33-level MMCC converter operating at 120 Vrms and 60 Hz.

Change visualisation: Analysing the resource and timing differences between two event logs

With organisations facing significant challenges to remain competitive, Business Process Improvement (BPI) initiatives are often conducted to improve the efficiency and effectiveness of their business processes, focussing on time, cost, and quality improvements. Event logs which contain a detailed record of business operations over a certain time period, recorded by an organisation's information systems, are the first step towards initiating evidence-based BPI activities. Given an (original) event log as a starting point, an approach to explore better ways to execute a business process was developed, resulting in an improved (perturbed) event log. Identifying the differences between the original event log and the perturbed event log can provide valuable insights, helping organisations to improve their processes. However, there is a lack of automated techniques to detect the differences between two event logs. Therefore, this research aims to develop visualisation techniques to provide targeted analysis of resource reallocation and activity rescheduling. The differences between two event logs are first identified. The changes between the two event logs are conceptualised and realised with a number of visualisations. With the proposed visualisations, analysts will then be able to identify the changes related to resource and time, resulting in a more efficient business process. Ultimately, analysts can make use of this comparative information to initiate evidence-based BPI activities.

Reducing the environmental impact of road construction

The practice of road construction and maintenance is inherently lean and efficient; a result of the economic benefits that are gained by minimizing wasted resources. In this age of conservation and environmental management, the inbuilt sustainability of existing road construction practices is being developed and extended to produce variety of environmentally sustainable options. A new concept of a “sustainable road” has emerged through both academia and industry, and is defined to be a road that is: - constructed to reduce environmental impacts; - designed to optimise the alignment (vertical and horizontal including considerations of ecological constraints and operational use by vehicles); - resilient to future environmental and economic pressures (e.g. climate change and resource scarcity); - adaptable to changing uses including increased travel volumes, greater demand for public and active (cycling and walking) transport, and; - able to harvest the energy to power itself.

Financially optimized scheduling of electric energy storage in presence of renewable energy resources

The increasing integration of Renewable Energy Resources (RER) and the role of Electric Energy Storage (EES) in distribution systems has created interest in using energy management strategies. EES has become a suitable resource to manage energy consumption and generation in smart grid. Optimize scheduling of EES can also maximize retailer’s profit by introducing energy time-shift opportunities. This paper proposes a new strategy for scheduling EES in order to reduce the impact of electricity market price and load uncertainty on retailers’ profit. The proposed strategy optimizes the cost of purchasing energy with the objective of minimizing surplus energy cost in hedging contract. A case study is provided to demonstrate the impact of the proposed strategy on retailers’ financial benefit.

Mining process risks and resource profiles

This research contributes novel techniques for identifying and evaluating business process risks and analysing human resource behaviour. The developed techniques use predefined indicators to identify process risks in individual process instances, evaluate overall process risk, predict process outcomes and analyse human resource behaviour based on the analysis of information about process executions recorded in event logs by information systems. The results of this research can help managers to more accurately evaluate the risk exposure of their business processes, to more objectively evaluate the performance of their employees, and to identify opportunities for improvement of resource and process performance.

Evaluation of social externalities of rapid economic development associated with major resource projects in regional communities

This thesis developed a thematic structure for evaluating social externalities of major resource projects using a mixed methods approach and structural equation modelling. The implications offer important insights into the extent quality of life is being influenced by coal seam gas projects in regional communities in Southeast Queensland, Australia. Findings show that unresolved concerns of community residents about environmental and social impacts contribute to lower life-satisfaction, inhibit the community to plan for the future, and lead to a weaker local economy.

School connectedness: Student voices examine power and subjectivity

Ideally, school would be a place where all students felt that they belonged. However, the reality is that many students feel as though they do not belong to their school community. Alienated or disaffected students are an endemic problem in schools in Australia, affecting the whole school community, as well as life chances for the students themselves after school. The crux of this matter, we believe, are the tensions between the desire to connect to the school community, and the frustration experienced by some students as a result of their subjectification by the school system. Perhaps students that we tend to identify as alienated or disaffected in their schools may be resisting the accepted negotiations of power that underpin the school system.

Modulating power and 'new weapons': Taking aim at the education revolution

This paper looks at the emergent performative culture seducing education in the Australian context. It links this corporate discourse to Deleuzean theorising of control societies to postulate that what we are experiencing is a new form of power relations – that of the modulating mechanisms of power. These modulating mechanisms overlay disciplinary power such that the self is modulated through the amplification and frequencies of the instruments of modulation: the simulation, the categorical sorting and the sample. These instruments are increasingly utilised within the performative culture of the Australian Federal Government’s Education Revolution as examples of the performative ‘terror’ or the abstraction of the self from the terrain in which they move. Finally, some new weapons are suggested that may offer preliminary and tentative ‘movement’ in deterritorialising ways through the enclosed spaces of mass, compulsory school and the policy that shapes it.