Improving power quality in low-voltage networks containing distributed energy resources

Severe power quality problems can arise when a large number of single-phase distributed energy resources (DERs) are connected to a low-voltage power distribution system. Due to the random location and size of DERs, it may so happen that a particular phase generates excess power than its load demand. In such an event, the excess power will be fed back to the distribution substation and will eventually find its way to the transmission network, causing undesirable voltage-current unbalance. As a solution to this problem, the article proposes the use of a distribution static compensator (DSTATCOM), which regulates voltage at the point of common coupling (PCC), thereby ensuring balanced current flow from and to the distribution substation. Additionally, this device can also support the distribution network in the absence of the utility connection, making the distribution system work as a microgrid. The proposals are validated through extensive digital computer simulation studies using PSCADTM

What are the offence and offender risk factors for Indigenous repeat drink drivers in Queensland?

In Australia and internationally, there is scant information about Indigenous repeat drink drivers. The aim was to identify the risk factors associated with repeat offending. De-identified data on drink driving convictions by offenders identifying as Indigenous in Queensland between 2006 and 2010 were examined. A range of univariate analyses were used to compare first time and repeat offenders on gender, age, court location and region (based on the accessibility/remoteness index of Australia), blood alcohol concentration and sentencing severity. Multivariate logistic regression adjusted for confounding variables. Convictions for repeat offenders were more likely from locations other than ‘major cities’ with the association strongest for courts in the ‘very remote’ region (OR=2.75, 2.06-3.76, p<.001). Indigenous offenders 40 years or older were found to be at reduced risk in comparison to offenders aged 15-24 years (OR=0.68, 0.54-0.86, p=0.01). After controlling for confounding factors, gender, sentencing severity and blood alcohol concentration levels were not significantly associated with recidivism. The association of recidivism and remoteness is consistent with higher rates of alcohol-related transport accidents involving Indigenous Australians in isolated areas. This study provides a platform for future research and allows for early attempts to address the need for intervention to reduce Indigenous drink driving recidivism.

Determinants of drink-driving and association between drink-driving and road traffic fatalities in Ghana

Aim The objective is to establish determinants of drink-driving and its association with traffic crashes in Ghana. Methods A multivariable logistic regression was used to establish significant determinants of drink-driving and a bivariate logistic regression to establish the association between drink–driving and road traffic crashes in Ghana. Results In total, 2,736 motorists were randomly stopped for breath testing of whom 8.7% tested positive for alcohol. Among the total participants, 5.5% exceeded the legal BAC limit of 0.08%. Formal education is associated with a reduced likelihood of drink-driving compared with drivers without formal education. The propensity to drink-drive is 1.8 times higher among illiterate drivers compared with drivers with basic education. Young adult drivers also recorded elevated likelihoods for driving under alcohol impairment compared with adult drivers. The odds of drink-driving among truck drivers is OR=1.81, (95% CI=1.16 to 2.82) and two wheeler riders is OR=1.41, (95% CI=0.47 to 4.28) compared with car drivers. Contrary to general perception, commercial car drivers have a significant reduced likelihood of 41%, OR=0.59, (95% CI=0.38 to 0.92) compared with the private car driver. Bivariate analysis conducted showed a significant association between the proportion of drivers exceeding the legal BAC limit and road traffic fatalities, p<0.001. The model predicts a 1% increase in the proportion of drivers exceeding the legal BAC to be associated with a 4% increase in road traffic fatalities, 95% CI= 3% to 5% and vice versa. Conclusion A positive and significant association between roadside alcohol prevalence and road traffic fatality has been established. Scaling up roadside breath test, determining standard drink and disseminating to the populace and formulating policies targeting the youth such as increasing minimum legal drinking age and reduced legal BAC limit for the youth and novice drivers might improve drink-driving related crashes in Ghana.

Are more city dwellers caught drink driving than country folk? An analysis by random breath testing apprehension rates

Background Random Breath Testing (RBT) remains a central enforcement strategy to deter and apprehend drink drivers in Queensland (Australia). Despite this, there is little published research regarding the exact drink driving apprehension rates across the state as measured through RBT activities. Aims The aim of the current study was to examine the prevalence of apprehending drink drivers in urban versus rural areas. Methods The Queensland Police Service provided data relating to the number of RBT conducted and apprehensions for the period 1 January 2000 to 31 December 2011. Results In the period, 35,082,386 random breath tests (both mobile and stationary) were conducted in Queensland which resulted in 248,173 individuals being apprehended for drink driving offences. Overall drink driving apprehension rates appear to have decreased across time. Close examination of the data revealed that the highest proportion of drink driving apprehensions (when compared with RBT testing rates) was in the Northern and Far Northern regions of Queensland (e.g., rural areas). In contrast, the lowest proportions were observed within the two Brisbane metropolitan regions (e.g., urban areas). However, differences in enforcement styles across the urban and rural regions need to be considered. Discussion and conclusions The research presentation will further outline the major findings of the study in regards to maximising the efficiency of RBT operations both within urban and rural areas of Queensland, Australia.

Alcohol restrictions and drink driving in remote Indigenous communities in Queensland, Australia

Alcohol restrictions have been implemented in many Indigenous communities internationally, with the aim to reduce alcohol-related harm. Whilst a range of reviews have evaluated such restrictions using different measures, drink driving has been described in several reviews as increasing. Presently, this remains anecdotal; with limited empirical evidence to corroborate these reports. In Australia, the Queensland government introduced alcohol management plans in remote Indigenous communities, during 2002-2003, with total alcohol prohibition commencing in 2008 in some communities. Given road crashes are one of the leading causes of injuries for Indigenous peoples, this study aims to identify if the restrictions have been successful in reducing drink driving or have increased such behaviour. We examine this by reviewing changes in conviction rates and in offender and offence characteristics following the 2008 restrictions. Using de-identified Queensland court drink driving conviction data (2006-2011), from four Indigenous communities, Robust Poisson regression models compared counts of drink driving convictions pre (2006-2008) versus post SRS (2009-2011). Changes in offender characteristics and conviction details (blood alcohol concentration (BAC) and sentencing severity), were examined using chi-squares. Results indicate a decline in convictions after the 2008 SRS in three communities. However, a significant increase in convictions was identified in one study community. Community-level disparity included significant decline in BAC in one community (χ 2=5.58, p=0.02) compared with the three other communities that did not indicate change and a significant increase the number of women convicted in two communities (χ 2=17.36, p<0.01; χ 2=5.79, p=0.04). Alcohol restrictions may have important implications in road safety with these reductions in convictions and BAC in some communities. However, an increase in the number of women convicted and limited changes in BAC for other communities demonstrate the complex relationship between alcohol use, remoteness and driving. Greater focus on demand reduction strategies may be necessary to address alcohol misuse.

Why do Indigenous Australians drink and drive? A qualitative exploration of self-reported influences on drink driving behaviours of Indigenous peoples from remote communities

Drink driving contributes towards high injury rates for Indigenous populations in Canada and Australia, particularly in more isolated regions. At present there is limited research on the cultural and psychosocial factors that underpin Indigenous peoples’ drink driving. This study is part of a broader project aiming to inform a culturally sensitive program. Qualitative interviews with 29 convicted Indigenous drink drivers (aged 20-51 years) from a remote region of Queensland, Australia were used to explore their cognitions about, and underlying motivation for, drink driving as well as the factors that might facilitate or impede it. Although a number of themes were identified, this paper will focus on the first theme, respondents’ self-perceived rationale for their behaviour. Two subthemes were identified: ‘being the hero’ referred to situations where respondents were motivated by a bravado mentality to drive after drinking despite having, on some occasions, the opportunity to avoid this (e.g. another person offering to drive); and ‘family obligations’ which referred to situations where respondents described pressure from members of their extended families to drive after drinking. The underlying responsibility for transporting family members appeared to be difficult to avoid and related to cultural values. Findings indicate the social and individual characteristics for younger drink drivers are similar to mainstream populations. However, the reinforcers for Indigenous drink drivers may be different for this population, consistent with findings on other Indigenous populations outside Australia. Specific programs should contain a family-centred approach and explore the kinship value system to build strategies around these strong relationships.

Prevalence and characteristics of Indigenous drink-driving convictions in Queensland, Australia

Alcohol-involved accidents are one of the leading contributors towards high injury rates among Indigenous Australians. However, there is limited information available to inform existing policies to change current rates. The study aims to provide information about the prevalence and the characteristics of such behaviour. Drink driving convictions from 2006-2010 were extracted from the Queensland Department of Justice and Attorney General database. Convictions were regrouped by gender, age, Accessibility/Remoteness Index of Australia classification (using court location) and sentence severity. A number of cross tabulations were carried out to identify relationships between variables. Standardised adjusted residuals were calculated for each cell in order to determine cell differences that contributed to the chi-square test results. Analysis revealed there were 9,323 convictions, of which the majority were for offences by males (77.5%). In relation to age, 52.6% of the convictions were of persons under 25 years of age. Age was significantly different across the five regions for males only (χ2=90.8, p<0.001), with a larger number of convictions in the ‘very remote’ region of persons over 40+ years of age. Increased remoteness was linked with high range BAC convictions for both males (χ2=168.4, p<0.001) and females (χ2=22.5, p=0.004). Monetary penalties were the primary sentence received for both males and females in all regions. The findings identify the Indigenous drink driving conviction rate to be 6 times that of the general Queensland rate and indicate that a multipronged approach is needed, with tailored strategies for remote offenders, young adults and offenders with alcohol misuse and dependency issues. Further attention is warranted in this area of road safety.

What are the offence and offender risk factors for Indigenous repeat drink drivers in Queensland Australia?

Background Road crashes contribute to high injury rates in Indigenous population in Aust, NZ, Canada and USA Alcohol one of the leading risk factors for road crashes: 31.5% Indigenous drivers in remote areas over 0.05mg/100ml, compared to 7.4 percent of non-Indigenous counterparts 17.5% Indigenous drivers in regional areas over 0.05mg/100ml compared to 3.8 percent of non-Indigenous counterparts Indigenous peoples are overrepresented in alcohol-related fatality rates, with this group 40% more likely to be killed

Theoretical and experimental characterisation of energy in an electrostatic discharge

Electrostatic discharges have been identified as the most likely cause in a number of incidents of fire and explosion with unexplained ignitions. The lack of data and suitable models for this ignition mechanism creates a void in the analysis to quantify the importance of static electricity as a credible ignition mechanism. Quantifiable hazard analysis of the risk of ignition by static discharge cannot, therefore, be entirely carried out with our current understanding of this phenomenon. The study of electrostatics has been ongoing for a long time. However, it was not until the wide spread use of electronics that research was developed for the protection of electronics from electrostatic discharges. Current experimental models for electrostatic discharge developed for intrinsic safety with electronics are inadequate for ignition analysis and typically are not supported by theoretical analysis. A preliminary simulation and experiment with low voltage was designed to investigate the characteristics of energy dissipation and provided a basis for a high voltage investigation. It was seen that for a low voltage the discharge energy represents about 10% of the initial capacitive energy available and that the energy dissipation was within 10 ns of the initial discharge. The potential difference is greatest at the initial break down when the largest amount of the energy is dissipated. The discharge pathway is then established and minimal energy is dissipated as energy dissipation becomes greatly influenced by other components and stray resistance in the discharge circuit. From the initial low voltage simulation work, the importance of the energy dissipation and the characteristic of the discharge were determined. After the preliminary low voltage work was completed, a high voltage discharge experiment was designed and fabricated. Voltage and current measurement were recorded on the discharge circuit allowing the discharge characteristic to be recorded and energy dissipation in the discharge circuit calculated. Discharge energy calculations show consistency with the low voltage work relating to discharge energy with about 30-40% of the total initial capacitive energy being discharged in the resulting high voltage arc. After the system was characterised and operation validated, high voltage ignition energy measurements were conducted on a solution of n-Pentane evaporating in a 250 cm3 chamber. A series of ignition experiments were conducted to determine the minimum ignition energy of n-Pentane. The data from the ignition work was analysed with standard statistical regression methods for tests that return binary (yes/no) data and found to be in agreement with recent publications. The research demonstrates that energy dissipation is heavily dependent on the circuit configuration and most especially by the discharge circuit's capacitance and resistance. The analysis established a discharge profile for the discharges studied and validates the application of this methodology for further research into different materials and atmospheres; by systematically looking at discharge profiles of test materials with various parameters (e.g., capacitance, inductance, and resistance). Systematic experiments looking at the discharge characteristics of the spark will also help understand the way energy is dissipated in an electrostatic discharge enabling a better understanding of the ignition characteristics of materials in terms of energy and the dissipation of that energy in an electrostatic discharge.

Vehicle energy throughput analysis as a drivetrain motor design aid

There are many variables to consider in the design of an electric motor. However, meeting the performance requirements for an electric vehicle drive may cause a designer to loose focus on its typical operation and hence fail to optimise the motor in the region where it processes the most power. This paper investigates operating requirements of electric vehicle motor drives using the University concept vehicle as an example. The paper outlines a methodology for determining primary operating region of a vehicle drive. The methodology is applied to standard driving cycles that are commonly used in the design and testing of vehicles.

Selection of energy storage system for a regenerative dynamic dynamometer

This paper presents a design technique of a fully regenerative dynamic dynamometer. It incorporates an energy storage system to absorb the energy variation due to dynamometer transients. This allows the minimum power electronics requirement at the grid to supply the losses. The simulation results of the full system over a driving cycle show the amount of energy required to complete a driving cycle, therefore the size of the energy storage system can be determined.

Migrating to a sustainable energy system : distributed generation and storage, fuel cells and hypercars

This paper examines a number of issues in sustainable energy generation and distribution, and explores avenues that are available for integration of our society’s energy supplies. In particular, the paper presents a way in which transport vehicle energy supplies could be integrated with distributed generation schemes to achieve synergistic and beneficial outcomes. The worldwide energy system contains fundamental problems that result directly from the use of unsustainable fuels and a lack of energy system integration. There is a need to adopt an integrated, sustainable energy system for our society. The adoption of distributed generation could result in beneficial restructuring of the energy trade, and a change in the role of energy providers. Inherent benefits in distributed generation schemes would directly combat barriers to installation of renewable generation facilities, which might prove distributed renewable energy sources to be more feasible. The presence of fuel cells, batteries, power electronic inverters and intelligent controls in vehicles of the future provides many opportunities for the integration of vehicle energy supplies into a distributed generation scheme. In such a system, vehicles could play a major role in power generation and storage.

Migrating to a sustainable energy system : distributed generation and storage, fuel cells and hypercars

This paper examines a number of issues in sustainable energy generation and distribution, and explores avenues that are available for integration of our society’s energy supplies. In particular, the paper presents a way in which transport vehicle energy supplies could be integrated with distributed generation schemes to achieve synergistic and beneficial outcomes. The worldwide energy system contains fundamental problems that result directly from the use of unsustainable fuels and a lack of energy system integration. There is a need to adopt an integrated, sustainable energy system for our society. The adoption of distributed generation could result in beneficial restructuring of the energy trade, and a change in the role of energy providers. Inherent benefits in distributed generation schemes would directly combat barriers to installation of renewable generation facilities, which might prove distributed renewable energy sources to be more feasible. The presence of fuel cells, batteries, power electronic inverters and intelligent controls in vehicles of the future provides many opportunities for the integration of vehicle energy supplies into a distributed generation scheme. In such a system, vehicles could play a major role in power generation and storage.

Optimisation of indoor environmental quality and energy consumption within office buildings

This research investigated airborne particle characteristics and their dynamics inside and around the envelope of mechanically ventilated office buildings, together with building thermal conditions and energy consumption. Based on these, a comprehensive model was developed to facilitate the optimisation of building heating, ventilation and air conditioning systems, in order to protect the health of their occupants and minimise the energy requirements of these buildings.

High energy states of gold and their importance in electrocatalytic processes at surfaces and interfaces

The ability of metals to store or trap considerable amounts of energy, and thus exist in a non-equilibrium or metastable state, is very well known in metallurgy; however, such behaviour, which is intimately connected with the defect character of metals, has been largely ignored in noble metal surface electrochemistry. Techniques for generating unusually high energy surface states for gold, and the unusual voltammetric responses of such states, are outlined. The surprisingly high (and complex) electrocatalytic activity of gold in aqueous media is attributed to the presence of a range of such non-equilibrium states as the vital entities at active sites on conventional gold surfaces. The possible relevance of these ideas to account for the remarkable catalytic activity of oxide-supported gold microparticles is briefly outlined.