The 230 V CBEMA curve - Preliminary studies

The ITI, formerly CBEMA, curve was developed by the Information Technology Industry Council of the United States of America. The curve describes an AC input voltage envelope which typically can be tolerated by most Information Technology (IT) Equipment. Although the curve ostensibly applies only to IT equipment it is often used throughout the electricity supply industry to provide an indication of the input voltage tolerance of a wide range of equipment. In spite of the fact that the curve was designed to apply to equipment supplied at 120 V 60 Hz nominal voltages it is widely used in Australia which has a 230 V 50 Hz system. This paper details a preliminary study aimed at developing a CBEMA style curve to suit Australian conditions. A range of domestic equipment has been tested to determine sag susceptibility. The types of equipment tested are not limited to IT equipment and represent a cross section of appliances likely to be found in most homes. Overall, results for domestic appliances show that equipment connected to the Australian 230 V network has sag immunity considerably greater than that defined by the ITI Curve. As such, the applicability of the curve for individual pieces of equipment connected to Australian 230 V electricity networks is highly questionable and the need for further work in this area is apparent

The electrical performance of modern compact fluorescent lamps

Compact Fluorescent Lamps (CFL) are highly non-linear devices which are likely to experience very high growth in penetration levels, especially in domestic environments, in Australia over the next 2 – 3 years. This will occur due to the decision taken by the Australian Federal Government to ban the sale of incandescent light globes after 2009 as measures towards meeting the needs for demand side management and climate change abatement. While CFL technology has been in existence since the late 1980s penetration levels are now increasing to a point where the total CFL load cannot be considered negligible compared to other non-linear domestic loads. This paper seeks to redress the lack of concise data available describing the performance of modern CFLs over a range of influence factors such as input voltage magnitude and harmonic distortion. It seeks to provide definitive characterisation of the modern CFL in terms of harmonic and power factor performance over a range of input supply conditions. This aim is achieved through laboratory testing of 25 CFLs of different brands, construction types and rated power levels

Monitoring intelligent distribution power systems: a power quality plan

Power system monitoring capabilities and requirements are evolving rapidly. The traditional monitoring framework in Australian distribution networks involves biannual readings of maximum demand at each distribution substation. As utilities respond to developments in metering and communications technology, automated collection and retrieval of quasi-real-time system data between substations and central repositories is now feasible. This gives network managers a significantly increased understanding of distribution network dynamic activity such as daily and seasonal load profiles. This leads to the increased ability of utilities to exploit metering data for power quality analysis purposes. This paper examines the scope for, and challenges associated with, integration of power quality monitoring with advanced metering. Emphasis is directed towards technical and regulatory conditions applying to Australian distribution utilities. Particular consideration is given to the different characteristics of the various types of sites where monitoring is required

Large Scale Proactive Power-Quality Monitoring: An Example from Australia

In Australia and many other countries, distribution network service providers (DNSPs) have an obligation to their customers to provide electrical power that is reliable and of high quality. Failure to do so may have significant implications ranging from financial penalties theoretically through to the loss of a license to distribute electricity. In order to ensure the reliability and quality of supply are met, DNSPs engage in monitoring and reporting practice. This paper provides an overview of a large long-running power-quality monitoring project that has involved most of Australia\u27s DNSPs at one time or another. This paper describes the challenges associated with conducting the project as well as some of the important outcomes and lessons learned. A number of novel reporting techniques that have been developed as part of the monitoring project are also presented. A discussion about large-volume data management, and issues related to reporting requirements in future distribution networks is included

HLA-DQA1*05 carriage associated with development of anti-drug antibodies to infliximab and adalimumab in patients with Crohn's Disease

Anti-tumor necrosis factor (anti-TNF) therapies are the most widely used biologic drugs for treating immune-mediated diseases, but repeated administration can induce the formation of anti-drug antibodies. The ability to identify patients at increased risk for development of anti-drug antibodies would facilitate selection of therapy and use of preventative strategies.This article is freely available via Open Access. Click on Publisher URL to access the full-text

Supply current charactersistics of modern domestic loads

The domestic load is considerably different to that seen 10 to 15 years ago. It has evolved significantly in terms of consumption and characteristics. In addition to traditional resistive and refrigeration type loads, the modern domestic load is now likely to contain a variety of sophisticated devices mostlypowered and controlled by power electronics. This paper examines the power quality characteristics of the modern domestic load. Laboratory testing and mathematical analysis is used to quantify and predict the behaviour of loads operating individually and in parallel. Specifically examined is thebehaviour and variation in harmonic current magnitudes across a variety of loads

Cause and effect of overvoltage on the LV network

Research at the Australian Power Quality & Reliability Centre has identified sustained overvoltage to be a common phenomenon with serious impacts on a range of components connected to the electricity supply network. Whilst there are many causes for the issue it has been determined that the continued proliferation of distributed energy resources like small scale PV solar systems, may have considerable influence on the network\u27s voltage. This paper investigates the reasons behind the continued increase in voltage levels and the impact it is having on connected devices. Research and experimental work has been carried out to quantify these effects showing that overvoltage scenarios can be detrimental to equipment lifetimes. The components of interest presented here are AC motors and Switch Mode Power Supplies. Suggestions to further revise the allowable voltage range in Australian low voltage distribution networks are also presented in the interests of mitigating the stress placed on components

Summary of the economic impacts of power quality on consumers

The quality of the electrical supply has a direct impact on the correct function and operation of equipment connected to the public electricity supply network. There is an expectation that devices will operate as designed and that equipment lifetime should, statistically, be close to the designed value. The reliability of the network is generally assumed to be high enough so as to not cause unacceptable issues with regard to loss of production or loss of functionality. Quantifying the cost to the consumer when the supply power quality or reliability are not as expected is an important metric and can be used as business case to justify expenditure in order to improve the supply network. This paper explores the research associated with quantifying the cost of reliability and power quality. Several power quality disturbances are investigated and possible methods of quantifying both the effect and cost are presented. Due to the complex nature of equipment performance with regard to power quality, there is a need for extensive research in order to develop a generalised approach to lifetime and cost evaluation

The Impact of Small Scale Solar PV on Power Quality: An Empirical Study

© 2020 IEEE. Australia has perhaps the highest penetration of small scale solar PV generation in the world. There is conjecture with regard to the impact that the inverters used to facilitate connectivity between solar PV generators and the grid will have on power quality disturbance levels. This paper has analysed power quality data collected from several thousand low voltage sites in order to facilitate an empirical investigation of the impact of small scale solar PV generation on PQ disturbance levels. The specific disturbances investigated are steady state voltage, voltage unbalance and voltage THD. The data analysed begins in 2009 when solar PV penetration was low in Australia and concludes with data from 2017. The study outcomes suggest that solar PV generation is leading to a change in the profile of voltage across the day and is increasing voltages to above light load levels at some sites. There is little evidence to support assertions that solar PV systems are increasing either voltage unbalance or voltage THD levels