Power Consumption Patterns Research Articles

RESIDENTIAL CUSTOMERS' OUTAGE COST ANALYSIS FOR URBAN AND SEMI-URBAN AREAS IN A DEVELOPING COUNTRY

This paper discusses cost of unreliability of electricity supply to the residential customers. Electricity supply outage cost is evaluated by customers' survey technique for urban and semi-urban residential areas of a developing country. The energy consumption pattern of urban and sub-urban areas is determined. Electricity supply outage cost is evaluated using both preparatory action approach and contingent valuation method. A detailed breakdown of customer's average outages costs for a entire day based on 8 three-hourly time durations are obtained that give easily understandable figures to the utilities. The power consumption pattern obtained are in close agreement with the utility's load curve. A MATLAB based computer program using Least Square Error Approximation is used to evaluate the outage cost.

CFD Investigation of the Mixing of Yield‐Pseudoplastic Fluids with Anchor Impellers

AbstractThe study was carried out to simulate the 3D flow domain in the mixing of pseudoplastic fluids possessing yield stress with anchor impellers, using a computational fluid dynamics (CFD) package. The multiple reference frames (MRF) technique was employed to model the rotation of the impellers. The rheology of the fluid was approximated using the Herschel–Bulkley model. To validate the model, the CFD results for the power consumption were compared to the experimental data. After the flow fields were calculated, the simulations for tracer homogenization were performed to simulate the mixing time. The effects of impeller speed, fluid rheology, and impeller geometry on power consumption, mixing time, and flow pattern were explored. The optimum values of c/D (impeller clearance to tank diameter) and w/D (impeller blade width to tank diameter) ratios were determined on the basis of minimum mixing time.

GIS-AMR 시스템에서 시공간 데이터마이닝 기법을 이용한 전력 소비 패턴의 분석 및 예측

이 논문에서는 자동 원격 검침(AMR) 시스템에서 수집되는 전력 사용량 데이터의 분석 결과를 실세계에 적용하기 위하여 시간과 공간의 변화에 따른 전력 소비 패턴의 주기성 탐사를 위한 시공간 데이터마이닝 기법을 제안하였다. 첫째, 고객의 전력 사용 목적에 따른 군집 분석을 위하여 분할 군집화 기법을 적용하였다. 둘째, 3차원 큐브 마이닝 기법을 적용하여 고객의 전력 소비 데이터가 갖는 시간 속성과 공간 속성에 대한 패턴을 탐색하였다. 셋째, 다양한 시간 도메인에서의 주기 패턴 발견을 위한 캘린더 패턴 마이닝 기법을 이용하여 탐사된 패턴들이 갖고 있는 시간 속성의 의미와 관계를 분석 및 예측하였다. 제안된 시공간 데이터마이닝 기법을 평가하기 위해 한국 전력 연구원에서 구축된 GIS-AMR 시스템에 의해 제공되는 고압 전력 소비 고객 3,256명의 2007년 1월부터 4월까지 총 266,426건의 데이터로부터 시간의 주기성 및 공간적 특성을 포함한 전력 소비 패턴을 분석하였다. 제안한 분석 기법을 통하여 특정 그룹에 속한 각각의 대표 프로파일이 시간과 공간상에서 갖는 주기성을 발견하였다. In this paper, the spatiotemporal data mining methodology for detecting a cycle of power consumption pattern with the change of time and spatial was proposed, and applied to the power consumption data collected by GIS-AMR system with an aim to use its resulting knowledge in real world applications. First, partial clustering method was applied for cluster analysis concerned with the aim of customer's power consumption. Second, the patterns of customer's power consumption data which contain time and spatial attribute were detected by 3D cube mining method. Third, using the calendar pattern mining method for detection of cyclic patterns in the various time domains, the meanings and relationships of time attribute which is previously detected patterns were analyzed and predicted. For the evaluation of the proposed spatiotemporal data mining, we analyzed and predicted the power consumption patterns included the cycle of time and spatial feature from total 266,426 data of 3,256 customers with high power consumption from Jan. 2007 to Apr. 2007 supported by the GIS-AMR system in KEPRI. As a result of applying the proposed analysis methodology, cyclic patterns of each representative profiles of a group is identified on time and location.

Spatial characterization of electrical power consumption patterns over India using temporal DMSP‐OLS night‐time satellite data

Changes in electric power consumption patterns of a country over a period of time reflect on its socio‐economic development and energy utilization processes. In the present study, we characterized spatial and temporal changes in electric power consumption patterns over India during 1993 to 2002, using ‘night‐time lights’ data given by the Defense Meteorological Satellite Program–Operational Line Scan System (DMSP‐OLS) over the Indian region. The OLS operates in two bands: visible (0.5–0.9 µm) and thermal (10.5–12.5 µm) and has a unique capability of picking up faint sources of visible–near infrared emissions (lights) at night on the Earth's surface including cities, towns and villages with a DN value ranging from 1 to 63. Night‐time light images for cloud‐free dates given by the DMSP‐OLS from 1993 to 2002 were segregated into respective years and were integrated to generate one ‘Stable light image’ per year. Changes in light scenarios over the Indian region in the decadal time frame were studied using stable lights datasets from 1993 to 2002. Information on changes in the light scenarios was integrated with demographic data to characterize developments in major cities and states of India. Results of the study suggested an increase in population by 170 million and power consumption from 44962 million kWh to 306355 million kWh over the country during 1993–2002, which was associated with an overall increase in number of night‐time lights of up to 26% in all states, indicating development in electric power consumption patterns. Correlation analysis between increase in population to the increase in night‐time lights and electric power consumption showed a coefficient of determination, R 2, of 0.59 and 0.56 respectively. Increase in light intensities along the peripheries of major Indian cities was observed, which indicated increased stress on the cities and corresponding development in power consumption patterns during the decadal time frame. Certain states, however, showed a decrease in night‐time lights in some areas, which are primarily attributed to the decreased economic growth trend and poverty and accounted to the scatter observed in the correlation analysis. Results are discussed in the paper.

What are the energy and power consumption patterns of different types of built environment?

This paper outlines the current energy usage patterns of various sectors of activity within the built environment. It then leads on to identify drivers and barriers to how energy consumption within the built environment could be reduced in the future.

Design considerations of sub-mW indoor light energy harvesting for wireless sensor systems

For most wireless sensor networks, one common and major bottleneck is the limited battery lifetime. The frequent maintenance efforts associated with battery replacement significantly increase the system operational and logistics cost. Unnoticed power failures on nodes will degrade the system reliability and may lead to system failure. In building management applications, to solve this problem, small energy sources such as indoor light energy are promising to provide long-term power to these distributed wireless sensor nodes. This article provides comprehensive design considerations for an indoor light energy harvesting system for building management applications. Photovoltaic cells characteristics, energy storage units, power management circuit design, and power consumption pattern of the target mote are presented. Maximum power point tracking circuits are proposed which significantly increase the power obtained from the solar cells. The novel fast charge circuit reduces the charging time. A prototype was then successfully built and tested in various indoor light conditions to discover the practical issues of the design. The evaluation results show that the proposed prototype increases the power harvested from the PV cells by 30% and also accelerates the charging rate by 34% in a typical indoor lighting condition. By entirely eliminating the rechargeable battery as energy storage, the proposed system would expect an operational lifetime 10--20 years instead of the current less than 6 months battery lifetime.

Power consumption pattern determination method to optimize electrical distribution system

Power consumption pattern determination method to optimize electrical distribution system

Effect of impeller design on the flow pattern and mixing in stirred tanks

The flow pattern and power number in a vessel depend on the impeller blade angle, number of blades, blade width, blade twist, blade thickness, pumping direction and interaction of flow with the vessel wall. Measurements of the power consumption and flow pattern have been carried out in a stirred vessel of 0.5 m diameter for the range of impellers to study the effect of blade shape on the flow pattern. The comparison of the flow pattern (average velocity, turbulent kinetic energy, maximum energy dissipation rate, average shear rate and turbulent normal stress) has been presented on the basis of equal power consumption to characterize the flow generated by different impeller geometries. Comparisons of LDA measurements and CFD predictions have been presented. The good comparison indicates the validity of the CFD model.

Effect of Internals on the Flow Pattern and Mixing in Stirred Tanks

The flow pattern, power consumption, and mixing time in a stirred vessel depend not only on the impeller design but also on the tank geometry and internals. Measurements of power consumption, mixing time, and flow pattern have been carried out in a stirred vessel of 0.5 m diameter for a standard 45° pitched-blade turbine and for a hydrofoil impeller with a variety of baffle and draft tube configurations. The comparison of the flow pattern (average velocity, turbulent kinetic energy, maximum energy dissipation rate, average shear rate, and turbulent normal stress) has been presented on the basis of equal power consumption to illustrate the extent of interaction between the rotating impeller and the internals. Comparisons of laser Doppler anemometer (LDA) measurements and computational fluid dynamics (CFD) predictions have been presented.

Energy Consumption Measurement of Wireless Interfaces in Multi-Service User Terminals for Heterogeneous Wireless Networks

For future generation mobile networks, we expect that the mobile devices like PDAs, note PCs or any VoIP-enabled communicators will have the feature of being always switched on, ready for service, constantly reachable by the wireless Internet. In addition to high access speed, attractive real-time contents or other expected spectacular features of the future wireless Internet environment, the mobile terminals has to be very much energy-aware to enable literal untethered movement of the user. Mechanisms for network activities like maintaining location information and wireless system discovery, which require regular network access, should be energy-efficient and resource-efficient in general. Cellular systems employ the notion of passive connectivity to reduce the power consumption of idle mobile hosts. In IP based Multi-service User Terminal (MUT) that may have multiple wireless interfaces for receiving various classes of services from the network, there should be an efficient addressing of the energy consumption issue. To devise an energy-efficient scheme for simultaneous or single operation of the wireless interfaces attached to such terminals we should have comprehensive understanding of the power consumption of the devices/modules in various operational states. This paper investigates the power consumption pattern or behavior of some selected wireless interfaces that are good candidates for being part of the future of the multi-service user terminals. We propose a simple model for predicting energy consumption in a terminal attributed to the wireless network interfaces. We measured the actual consumption pattern to estimate the parameters of the model.

The proposal of power analysis for common key cryptography implemented on the FPGA and its countermeasure

With recent advances in networks and IT equipment, cryptography is now used in many different areas. On the other hand, research is being carried out to attack systems equipped with cryptography and to infer key information. The main attack methods are cryptographic analysis and side channel attack. Side channel attack is a technique for inferring key information from information on power consumption at the time of processor operation and the time needed for cryptographic processing, in addition to the cryptographic content and the corresponding clear-text sentences. As cryptography is used in more areas, side channel attack has drawn more attention. Among side channel attacks, differential power analysis is a powerful method of analysis in which many of the power consumption patterns of the processors under operation are collected and statistical processing is applied to them. In differential power analysis, one bit in an intermediate variable dependent on the key information is noted and the power consumption pattern dependent on this variable is analyzed. However, due to advances in miniaturization of devices and voltage reduction, it is becoming difficult to detect power consumption patterns dependent on the key if conventional differential power analysis is used. In the present paper, all bits of the intermediate variable dependent on the key information are noted. A moving average line is derived from statistical processing of the results of the power difference analysis of each bit and the statistically processed waveforms. Then, the difference in amplitude from the moving average line is used in the proposed evaluation method. By the proposed method, key dependent patterns can be detected even in a low-voltage device. Experiments are carried out on the encryption capabilities installed on FPGA manufactured by the latest process. Countermeasures to the proposed method are discussed. © 2005 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 88(8): 28–37, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.20140

A new methodology for nodal load forecasting in deregulated power systems

A neurofuzzy methodology for online nodal load prediction is introduced that exploits the power of artificial neural networks (ANN) and fuzzy logic. ANNs are used to capture the power consumption patterns specific to a customer, while a fuzzy logic module detects departures from equilibrium (that is, previously established consumption patterns). The fuzzy-logic-based (FL) module (called PROTREN) performs signal trend identification. The proposed methodology improves the adaptability of the forecasting system to sudden changes or special events that may influence the load by temporarily distorting the general pattern and thus rendering the load signal highly unpredictable. Experiments have been performed to verify the effectiveness of the new methodology. Results show that the methodology has a better performance than those using traditional forecasting methodologies, especially when special events influencing the load occur.

The need for training in the desalination industry

Population, industrial, and agriculture growth in Indonesia combined with limited water resources have resulted in initiation of an active desalination program at the Badan Tenaga Atom Nasional (BATAN) of Indonesia. Water shortages are experienced in several regions of Indonesia and have resulted in limitations on industrial activities and affected the welfare of the communities in these regions. In addition, underground water in several areas, which had been considered as an unlimited source of fresh water, was affected by overuse, reduced the water quality and increased its salinity. Desalination activities at BATAN started in 1999 with two training courses; the first focused on use of the DEEP economic cost evaluation program of the IAEA and the second focused on desalination fundamentals. This was followed by preparation of a long-term plan on qualifying the desalination manpower in Indonesia. The plan was put forward by El-Dessouky and Ettouney and was evaluated in the summer of 2000. The ultimate goal of the desalination program is the construction and operation of a 5000m 3/d mechanical vapor compression unit (MVC). The BATAN desalination group will conduct the design, construction and operation of this unit. To reach this goal a desalination program that includes manpower training, experimental research, and system design will be adopted. The manpower training includes introductory and advanced levels of intensive courses on desalination. The experimental research includes a number of studies on desalination including scaling, evaporation, condensation, and use of plastic materials. The proposed desalination program also interacts with a number of local studies on industrial resources, power and water requirements and consumption patterns in Indonesia. Finally, a regional/international desalination conference will be organized in part by BATAN to shed light on desalination needs and to mobilize and raise interest among various local organizations.

Battery state judging apparatus

A battery state judging apparatus comprising a voltage detector detecting a voltage at a terminal of a battery, a current detector detecting a charge/discharge current of the battery and an arithmetic operation circuit calculating a residual capacity index of the battery relating to a value obtained by subtracting a quantity of electric charge from a reference capacity value of the battery and calculating a power consumption of the battery from the detected terminal voltage and charge/discharge current. The arithmetic operation circuit estimates a charge/discharge current as a function of the battery residual capacity index and battery power consumption and successively estimates a charge/discharge current in a predetermined power consumption pattern to successively calculate a battery residual capacity index from the estimated charge/discharge current. A battery operable threshold is judged when a battery discharge current, estimated on the basis of an updated battery residual capacity index exceeds a threshold current at that power consumption, and a result is displayed via a display circuit.

The application of artificial neural networks to substation load forecasting

The substation loading is highly correlated with the customers served. The substations in a distribution system can be categorized as residential, commercial and industrial. Each type has a different power consumption pattern. The substation loading will be varied according to the combination of the above three types of customers. In this paper, a supervisory functional artificial neural network (ANN) technique is applied to solve the load forecasting of three Taipower substations which serve the different customer types. The load forecasting accuracy is enhanced by considering the temperature effect on the substation load demand. With the converged ANN models derived by a training procedure, the temperature sensitivity of the substation load demand is easily obtained by the recall process. It is suggested that the substation load forecasting can be performed efficiently by the proposed method to support distribution operation effectively.

Studies on the Granulation Process of Granules for Tableting with a High Speed Mixer. II. Influence of Particle Size of Active Substance on Granulation.

In the process of granulation for tableting using theophylline as a model drug, the power consumption pattern and the physical properties of the granules were examined with varied particle sizes of theophylline. During kneading of the physical mixtures containing these varied particle sizes into granules for tableting, the first peak of the power consumption curve declined with decreasing particle size of the physical mixtures and a second peak appeared for physical mixtures with smaller particle sizes. The optimal kneading end point for granules was at the end of the first peak for mixtures with larger particles and at the beginning of the second peak for those with smaller particles.The best granules for tableting prepared from individual physical mixtures at different end points had maximum pore volume and consisted of a mixture of similar size of porous loose agglomerates and bulk powder as reported previously. This inner structure of granules is assumed to induce plastic deformation and particle movement upon compression and to result in high mechanical tablet strength.

Time-of-use pricing for load management programs in Taiwan Power Company

Load management programs have been actively performed by the utilities to reduce peak demand and improve system load factor. In recent years, the time-of-use (TOU) tariff based on the peak load pricing theory has been one of the most effective load management strategies. Proper TOU rate structure can actually reflect the generation cost of electricity supplying and give a guideline for customers to modify the power consumption pattern so that the system load factor can be improved. The inverse electricity pricing rule can be applied as the basis of TOU pricing. In this paper, the price-elasticities of industrial customers of Taipower system are solved by the statistical regression model with 2620 data samples.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Cultivation of plant cells in a stirred vessel: Effect of impeller design

Suspension cultures of Nicotiana tabacum were grown in a batch fermentor using different agitation systems. The effects of the impeller type, size, and agitation speed on the productivity of cell mass and secondary metabolites (phenolics) have been investigated. The use of a large, flat-bladed impeller (diameter 7.6 cm; width 14.0 cm) improved culture growth significantly over systems using a regular, flat-bladed impeller (diameter 5.6 cm; width 1.5 cm). An impeller of the same dimensions as the 14.0-cm-wide, large, flat-bladed impeller with sail cloth blades yielded a higher maximum growth rate in the exponential phase but resulted in a longer lag phase. Overall (intracellular and extracellular) phenolics concentration showed a direct relationship to culture growth rate whereas extracellular concentrations were a function of agitation conditions. Power consumption and flow pattern studies were also completed to further characterize the different impellers tested.

Gas–liquid dispersion with dual Rushton impellers

Aerated and unaerated power consumption and flow patterns in a 0.56 m diameter agitated vessel containing water with dual Rushton turbines have been studied. Under unaerated conditions with a liquid height-to-diameter ratio of 2, an impeller spacing of 2 to 3 times the impeller is required for each to draw an amount of power equal to a single impeller. For aerated conditions, if a similar spacing is used, equations for the flooding-loading transition and for power consumption for a single Rushton impeller can be extended relatively easily to dual systems. All results for this spacing are explained by reference to bulk flow patterns and gassed-filled cavity structures and the proportion of sparged gas flowing through the upper impeller is also estimated. Such a spacing is generally recommended since it maximizes the power draw and hence the potential for oxygen mass transfer. Data are presented for other spacings but the results do not fit in easily with single agitator studies because strong impeller-impeller flow pattern interactions occur.

Sunday decreases in magnetospheric VLF wave activity

Magnetospheric wave intensity in the 2‐ to 4‐kHz range was monitored on the ground at Siple, Antarctica, in 1974 and 1975. Sampled broadband spectral data show that the wave activity in the 2‐ to 4‐kHz band is predominantly chorus (discrete narrow band emissions). The measured wave intensity shows a distinct minimum on Sunday in comparison with the rest of the week. The Sunday minimum is confined to the dawn‐afternoon local time sector where the chorus intensity has a diurnal maximum. It is suggested that much of the chorus observed at Siple is triggered in the magnetosphere by power line radiation from its conjugate region in eastern Canada and that the Sunday minimum in magnetospheric wave activity is the result of reduced power consumption on Sunday. This interpretation is supported by the results of an independent study based on broadband spectral data from Siple between 1973 and 1975. The results show weekly variations in the occurrence of strong power‐line‐induced emissions with a pronounced minimum on Sunday. This pattern is similar to the power consumption pattern in Quebec. It appears that power line radiation is an important factor in the overall magnetospheric wave environment. Its role in particle precipitation (through wave‐particle interaction) needs to be investigated.