Quantitative assessment of fault tolerant precision timing for electricity substations

Advanced substation applications, such as synchrophasors and IEC 61850-9-2 sampled value process buses, depend upon highly accurate synchronizing signals for correct operation. The IEEE 1588 Precision Timing Protocol (PTP) is the recommended means of providing precise timing for future substations. This paper presents a quantitative assessment of PTP reliability using Fault Tree Analysis. Two network topologies are proposed that use grandmaster clocks with dual network connections and take advantage of the Best Master Clock Algorithm (BMCA) from IEEE 1588. The cross-connected grandmaster topology doubles reliability, and the addition of a shared third grandmaster gives a nine-fold improvement over duplicated grandmasters. The performance of BMCA mediated handover of the grandmaster role during contingencies in the timing system was evaluated experimentally. The 1 µs performance requirement of sampled values and synchrophasors are met, even during network or GPS antenna outages. Slave clocks are shown to synchronize to the backup grandmaster in response to degraded performance or loss of the main grandmaster. Slave disturbances are less than 350 ns provided the grandmaster reference clocks are not offset from one another. A clear understanding of PTP reliability and the factors that affect availability will encourage the adoption of PTP for substation time synchronization.

Ask : a health advocacy program for adolescents with an intellectual disability : a cluster randomised controlled trial

Background Adolescents with intellectual disability often have poor health and healthcare. This is partly as a consequence of poor communication and recall difficulties, and the possible loss of specialised paediatric services. Methods/Design A cluster randomised trial was conducted with adolescents with intellectual disability to investigate a health intervention package to enhance interactions among adolescents with intellectual disability, their parents/carers, and general practitioners (GPs). The trial took place in Queensland, Australia, between February 2007 and September 2010. The intervention package was designed to improve communication with health professionals and families’ organisation of health information, and to increase clinical activities beneficial to improved health outcomes. It consisted of the Comprehensive Health Assessment Program (CHAP), a one-off health check, and the Ask Health Diary, designed for on-going use. Participants were drawn from Special Education Schools and Special Education Units. The education component of the intervention was delivered as part of the school curriculum. Educators were surveyed at baseline and followed-up four months later. Carers were surveyed at baseline and after 26 months. Evidence of health promotion, disease prevention and case-finding activities were extracted from GPs clinical records. Qualitative interviews of educators occurred after completion of the educational component of the intervention and with adolescents and carers after the CHAP. Discussion Adolescents with intellectual disability have difficulty obtaining many health services and often find it difficult to become empowered to improve and protect their health. The health intervention package proposed may aid them by augmenting communication, improving documentation of health encounters, and improving access to, and quality of, GP care. Recruitment strategies to consider for future studies in this population include ensuring potential participants can identify themselves with the individuals used in promotional study material, making direct contact with their families at the start of the study, and closely monitoring the implementation of the educational intervention.

Applied sub-transmission & distribution reliability assessment of SEQEB network in Queensland

In this paper a combined subtransmission and distribution reliability analysis of SEQEB’s outer suburban network is presented. The reliability analysis was carried out with a commercial software package which evaluates both energy and customer indices. Various reinforcement options were investigated to ascertain the impact they have on the reliability of supply seen by the customers. The customer and energy indices produced by the combined subtransmission and distribution reliability studies contributed to optimise capital expenditure to the most effective areas of the network.

Multi-area reliability assessment of interconnected generating systems using hybrid approach

This paper present an efficient method using system state sampling technique in Monte Carlo simulation for reliability evaluation of multi-area power systems, at Hierarchical Level One (HLI). System state sampling is one of the common methods used in Monte Carlo simulation. The cpu time and memory requirement can be a problem, using this method. Combination of analytical and Monte Carlo method known as Hybrid method, as presented in this paper, can enhance the efficiency of the solution. Incorporation of load model in this study can be utilised either by sampling or enumeration. Both cases are examined in this paper, by application of the methods on Roy Billinton Test System(RBTS).

An assessment for cost effective maintenance and operation of the Callide Power Station electrical system, using reliability evaluation

The reliable operation of the electrical system at Callide Power Station is of extreme importance to the normal everyday running of the Station. This study applied the principles of reliability to do an analysis on the electrical system at Callide Power Station. It was found that the level of expected outage cost increased exponentially with a declining level of maintenance. Concluding that even in a harsh economic electricity market where CS Energy tries and push their plants to the limit, maintenance must not be neglected. A number of system configurations were found to increase the reliability of the system and reduce the expected outage costs. A number of other advantages were identified as a result of using reliability principles to do this study on the Callide electrical system configuration.

Maintenance considerations in applied substation reliability assessment

This paper presents a reliability assessment of a substation, part of the Queensland transmission network in Australia. As part of a maintenance considerations, this study utilises the substation reliability assessment package STAREL to quantitatively compare the reliability improvement achieved by two circuit breaker reinforcement alternatives for Swanbank circuit breaker replacement or refurbishment. Substation reliability is interpreted on the basis of outage frequency and outage duration indices for each individual transmission line terminated in Swanbank 'B' substation. By considering the reliability indices in this paper with the cost associated conducted by POWERLINK Queensland, a Swanbank 'B' reinforcement alternative can be selected that optimises both transmission line security and the costs incurred in achieving it.

Towards improving public understanding of judgement practice in standards-referenced assessment : an Australian perspective

Internationally there has been a move towards standards-referenced assessment with countries such as Australia developing a National Curriculum and Achievement Standards, New Zealand adopting National Standards for literacy and numeracy that involve schools making and reporting judgements about the reading, writing and mathematics achievement of children up to Year 8 (the end of primary school) and in Canada, classroom assessment standards aimed at the improvement of assessment practice of K-12 education are being formulated. Standards-driven reform has major implications for teachers’ work. The consequences of adopting a standards-driven approach to educational change by systems are often under-estimated with the unintended effects not fully understood by either the policy writers, and the public, including parents. It is for these reasons that the contention developed in this article relates to the teacher’s role, which it is argued remains central to policy focused on the improvement of the quality of education and educational standards.

Dichotomy in the design studio : adapting to new blended learning environments

Since the architectural design studio learning environment was first established in the early 19th century at the École des Beaux-Arts in Paris, there has been a complete transformation in how the discipline of architecture is practiced and how students of architecture acquire information. Digital technologies allow students to access information instantly and learning is no longer confined to the rigid boundaries of a physical campus environment. In many schools of architecture in Australia, the physical design studio learning environments however, remain largely unchanged. Many learning environments could be mistaken for those last refurbished 30 years ago, being devoid of any significant technological intervention. While some teaching staff are eagerly embracing new digital technologies and attempting to modify their pedagogical approaches, the physical design studio learning environment is resistant to such efforts. In a study aimed at better understanding how staff and students adapt to new blended learning environments, a group of 165 second year architecture students at a large school of architecture in Australia were separated into two different design studio learning environments. 70% of students were allocated to a traditional design studio setting and 30% to a new, high technology embedded, prototype digital learning laboratory. The digital learning laboratory was purpose designed for the case-study users, adapted Student-Centred Active Learning Environment for Undergraduate Programs [SCALE-UP] principles, and built as part of a larger university research project. The architecture students attended the same lectures, followed the same studio curriculum and completed the same pieces of assessment; the only major differences were the teaching staff and physical environment within which the studios were conducted. At the end of the semester, all staff and students were asked to complete a questionnaire about their experiences and preferences within the two respective learning environments. The questionnaire response rate represented the opinions of 100% of the 10 teaching staff and over 70% of the students. Using a qualitative grounded theory approach, data were coded, extrapolated and compared, to reveal emerging key themes. The key themes formed the basis for in-depth interviews and focus groups of teaching staff and students, allowing the researchers to understand the data in more detail. The results of the data verified what had become increasingly evident during the course of the semester: an underlying negative resistance to the new digital studio learning environment, by both staff and students. Many participants openly exhibited a yearning for a return to the traditional design studio learning environments, particularly when the new technology caused frustration, by being unreliable or failing altogether. This paper reports on the study, discusses the negative resistance and explores the major contributors to resistance. The researchers are not aware of any similar previous studies across these particular settings and believe that it offers a necessary and important contribution to emergent research about adaptation to new digital learning environments.

Email as an arena for authoring a dialogical self among gifted young adolescents : a qualitative study

This paper describes a qualitative study that investigated young adolescents’ self-constructions within the context of online (email) communication. Drawing from dialogical perspectives of self as multiply-situated and complex phenomena, the study focused on the everyday narratives of individual young adolescents interpreted as different “I” voices. With the assumption that computer mediation offers cultural relevance and empowerment to young adolescents, techniques of personal journal writing were used in combination with email as an alternative to face-to-face methods. Twelve participants aged 10 to 14 years were recruited online and by word-of-mouth with an invitation to write freely about their lives over a six month period in a participant-led email journal project. The role of the researcher was to develop a supportive voice of listener/responder that was intended to facilitate the emergence of participants’ own ‘self’ voices within an interactive space for relatively autonomous self-expression. Data as email texts were analysed using a close listening method that synchronised with the theory by revealing multi-layered patterns and shifts of voices in order to give a nuanced understanding of participants’ self and other evaluations. The paper shows that narrative methods used online and in concert with dialogical concepts have potential to heighten self-reflection and strengthen agency as a means to access rich and nuanced data from young adolescent individuals. The study’s findings contribute to a growing interest in the use of dialogical concepts to explore the ways people engage in active meaning-making while embedded in their specific social and cultural environments.

Court overrides costs assessment limits

This article considers the implications for Queensland practitioners of the decision of the New South Wales Court of Appeal in Branson v Tucker [2012] NSWCA 310. That decision involved the question whether the court retained a jurisdiction to examine the reasonableness of costs charged by a barrister, who had entered a costs agreement with solicitors, in circumstances where where had been no application under the Legal Profession Act 2004 (NSW) for an assessment of the costs the subject of the bill and it was no longer possible for such an application to be made.

A qualitative think aloud study of the early Neo-Piagetian stages of reasoning in novice programmers

Recent research indicates that some of the difficulties faced by novice programmers are manifested very early in their learning. In this paper, we present data from think aloud studies that demonstrate the nature of those difficulties. In the think alouds, novices were required to complete short programming tasks which involved either hand executing ("tracing") a short piece of code, or writing a single sentence describing the purpose of the code. We interpret our think aloud data within a neo-Piagetian framework, demonstrating that some novices reason at the sensorimotor and preoperational stages, not at the higher concrete operational stage at which most instruction is implicitly targeted.