Power Quality Assessment and Its Outlooks for Further Research,Xiao Xiangning North China Electric Power University, China September 15, 10:40-11:10,CICED2010, Nanjing, 12-16day; development of the power supply system for more intelligent,Contents,Backgrounds Voltage sags assessment Extensive Voltage Sag Characteristics Assessed Power Quality Economics Corrected Reliability Indices based on Economics Voltage deviation assessment Reasonable Assessment Interaction Between DER and Quality Assessment Outlooks for power quality assessment Conclusion,Background,Smart Grid Research is becoming a focusing issue.,Background Voltage sags Deviations Outlooks Conclusion,Smart Grid in China Can Achieve 10.5 Billion Tons of Carbon Emission Reduction over the Next Decade,Strong Smart Gridin China,Backgrounds,After analyzing to the adverse impaction of SG, an expert of PQ standardization in USA, prof. McEachern said if the research work not to do on PQ problems same times, smart grid will make power quality worse, not better. Power quality control should be regarded as a important part of smart grid . But the benefits of SG are great, so it should continue,Backgrounds,A power quality disturbance can be defined as a deviation from the ideal (sinusoidal, constant magnitude) voltage or current. Based on the monitored data or simulated data of power system operating parameters, power quality assessment, which is a very important part of power quality research area, is a process of calculating the quality indices and checking whether the values fulfill the standard limitation, or whether the power disturbances make equipments miss-function.,Background Voltage sags Deviations Outlooks Conclusion,Backgrounds,The power quality standards should be improved on the basis of further research, though a set of useful standards have been published. The changes of power load constitution, the development of distributed generators, and the integration of large scale new sources, resulted from the construction of Smart Grid, will introduce challenges and opportunities for new sufficient important and interesting research in the domain of power quality.,Background Voltage sags Deviations Outlooks Conclusion,Extensive Voltage Sag Characteristics Assessed,Voltage sags are, according to standards, characterized by one magnitude and one duration. Other indices are still in dispute. IEC 61000-4-30, IEC61000-2-2（12,8), IEC61000-4-11(34) IEEE std 493, IEEE std 1346 CIGRE C 4.07 SEMI 47 EN 50160 NRS 048 but there are many new indices are discussed and studied in,Background Voltage sags Deviations Outlooks Conclusion,Extensive Voltage Sag Characteristics Assessed,From the view of influenced equipment, manufacturers, as well as power suppliers, should be aware of more characteristics than just magnitude and duration.,Background Voltage sags Deviations Outlooks Conclusion,Extensive Voltage Sag Characteristics Assessed,CIGRE/CIRED/UIE Joint Working Group C4.110 Voltage Dip Immunity of Equipment and Installations(2010.04) For characterizing dip immunity of three-phase equipment, voltage-tolerance curves should be given for three general dip types: Type I, Type II and Type III dips.,Background Voltage sags Deviations Outlooks Conclusion,Power quality economics-sags,The economic cost assessment of power quality and the profit and loss analysis of power quality investment have contributed to the development of power quality industry and power quality economics. CIGRE JWG C4.107- Economic Framework for Voltage Quality Propose a standardized method of collecting information, based on the experience of various international studies. Recommend a methodology of using these data to cost and motivate power quality interventions on the power system or within the customer plant. Provide indicative costs for specific industry sectors, where possible. Provide detail the main factors influencing decisions about the investment in increased immunity of equipment. Voltage sags are the most concerned voltage quality disturbances and Economics on sags is a critical study because the costs are very significant.,Background Voltage sags Deviations Outlooks Conclusion,E.g. Cost of downtime is dependent on many factors.,Voltage dip pattern with time of the day.,varying customer size in annual kWh consumption,varying season and time of day,varying business type,Corrected reliability indices based on economics,Besides sustained interruptions, voltage sags and short-duration interruptions disturb the continuous operation of customers especially, of typical continuous manufacturing plants. SAIDI the average interruption duration of the customers served SASDI Average sag economic equivalent interruption duration,Background Voltage sags deviations outlooks Conclusion,Example of a contour chart: HV/MV sites (CP95 value ) Customer Sag Frequency the number of sag events for the customer per year CSF(Vs=80%,T=100ms,Type=Type III) =35 per year,Type I,Type II,Type III,