There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

THE DESIGN AND ANALYSIS OF EXPERIMENTS. By Oscar Kempthorne. New York, John Wiley and Sons, Inc., 1952. 631 pp. $8.50. This book by a teacher of statistics (as well as a consultant for \"experimenters\") is a comprehensive study of the philosophical background for the statistical design of experiment. It is necessary to have some facility with algebraic notation and manipulation to be able to use the volume intelligently. The problems are presented from the theoretical point of view, without such practical examples as would be helpful for those not acquainted with mathematics. The mathematical justification for the techniques is given. As a somewhat advanced treatment of the design and analysis of experiments, this volume will be interesting and helpful for many who approach statistics theoretically as well as practically. With emphasis on the \"why,\" and with description given broadly, the author relates the subject matter to the general theory of statistics and to the general problem of experimental inference. MARGARET J. ROBERTSON

The Design and Analysis of Experiments

计量经济分析 = Econometric analysis

This chapter discusses leading problems linked to energy that the world is now confronting and to propose some ideas concerning possible solutions. Oil deserves special attention among all energy sources. Since the beginning of 1981, it has merely been continuing and enhancing the downward movement in consumption and prices caused by excessive rises, especially for light crudes such as those from Africa, and the slowing down of worldwide economic growth. Densely-populated oil-producing countries need to produce to live, to pay for their food and their equipment. If the economic growth of the industrialized countries were to be 4%, even if investment in the rational use of energy were pushed to the limit and the development of nonpetroleum energy sources were also pursued actively, it would be extremely difficult to prevent a sharp rise in prices. It is evident that it is absolutely necessary to pursue actively the development of coal, natural gas, and nuclear power if a physical shortage of energy is not to block economic growth.

World energy outlook

Introduction to stochastic programming

Increasing the intermittent outputs of renewable energy sources (RESs) has forced planners to deﬁne a new concept named ﬂexibility. In this regard, some short- and long-term solutions, such as transmission expansion planning (TEP) and energy storage systems (ESSs) have been suggested to improve the ﬂexibility amount. A proper optimization procedure is required to choose an optimal solution to improve ﬂexibility. Therefore, a mixed-integer linear programming (MILP) direct-optimization TEP versus ESSs coplanning model is presented in this paper to enhance power system ﬂexibility. In doing so, a novel RES-BESS-based grid-scale system ﬂexibility metric is proposed to investi-gate the improvement of ﬂexibility amount via ESSs modules in the numerical structure. In this paper, a novel repetitive fast ofﬂine method has been proposed to quickly reach the desired amount of ﬂexibility by deﬁning an engineering price/beneﬁt trade-off to ﬁnally ﬁnd the best investment plan. Also, multiple uncertainties associated with wind farms and demanded loads and a practical module-type battery energy storage system (BESS) structure for each node are deﬁned. The proposed model is applied to the modiﬁed IEEE 73-bus test system including wind farms, where the numerical results prove the model efﬁciency as BESS impacts on ﬂexibility, investment plans and power system

Harnessing power system flexibility under multiple uncertainties

This paper describes the lightning overvoltage protection schemes of cable laterals connected with MV overhead line. The various protection schemes are modelled and investigated are carried out on the simulation results. The simulations are performed using EMTP-ATP simulation environment, which is a strong tool to analysis transient behaviour of MV network components. The simulated lightning surge is struck on one of the overhead line phases and overvoltage effects are investigated down the cable connected with overhead line. The cable laterals are consisted of sub-laterals which are also simulated in this study. Generally, the surge arresters are installed at the junction of overhead line and cable and at far end of the cable. The various mitigation methods and protection schemes for protecting MV cable laterals are proposed on the basis of surge arresters locations, sub-laterals connections, and cable length. DOI: http://dx.doi.org/10.5755/j01.eee.123.7.1325

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Modelling and analysis of lightning overvoltage protection of MV cable laterals connected with overhead lines

This paper proposes a scheme to locate an earth fault in an unearthed or a compensated neutral medium voltage (MV) network using the transient signal recorded from MV/LV substations. The algorithm applies continuous wavelet Transform (CWT) to locate the dominant charge transient frequency and then fast Fourier transform (FFT) to extract coefficients to be used in the fault location scheme. The fault location scheme managed to identify the correct path of fault location towards the position of the fault using the transient signal recorded from secondary side of the LV substation transformers. The results from intensive simulations and experiments in actual distribution network are also presented in this paper. The final results show that the fault location scheme is able to locate and identify the correct fault location successfully.

An Earth Fault Location Scheme for Isolated and Compensated Neutral Distribution Systems

This work aims at proposing a strategy based on an environmental and technical perspective to assess the amount of distributed generation (DG) that can be deployed into an electric distribution network (EDN). The presented approach seeks to minimize the carbon emissions and energy losses while the installed capacity of renewable DG units is maximized. To enable the DG integration without requiring EDN upgrading, the operations of capacitor banks (CBs) and voltage regulators (VR) devices are optimized simultaneously. To analyze the relationship between the installed DG and demand consumption, the effects of voltage-dependent loads are investigated. Several test cases are studied in a 42-node distribution network. Results show that by applying operating actions and determining the hosting capacity of the EDN for deploying DG units, environmental and technical benefits could be achieved.

Increasing Distributed Generation Hosting Capacity in Distribution Networks: A CO 2 Emission Analysis

Automatic loop restoration schemes are employed in electric power distribution systems to perform fault detection, isolation, and service restoration activities sequentially and automatically, so as to significantly reduce customer interruption time This paper aims to quantitatively assess the impacts of employing an automatic loop restoration scheme, with and without a communication link, on the major attributes of the service reliability In addition, the effect of the operational failure of communication facilities is taken into account A typical Finnish urban distribution network is utilized in this paper for the quantitative reliability assessment studies A powerful software package referred to as "Smart Grid Simulator" is used for directing the reliability studies (6 pages)

Matti Lehtonen

Papers

Harnessing power system flexibility under multiple uncertainties

Modelling and analysis of lightning overvoltage protection of MV cable laterals connected with overhead lines

An Earth Fault Location Scheme for Isolated and Compensated Neutral Distribution Systems

Increasing Distributed Generation Hosting Capacity in Distribution Networks: A CO 2 Emission Analysis

Impacts of automatic loop restoration schemes on service reliability