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

One of the traditional load shifting motivations in use for long time already is the two-level time-of-use tariff scheme. The nighttime lower energy has been known to provide lower cost for the homeowners who are using electric energy for space heating. The measurements of residential areas, presented in this paper, confirm that the load shift towards the times of lower pricing is used by many homeowners to benefit from this. This brings high load power peaks for the distribution network for some shorter periods after the pricing is changed. When introducing EV charging to the household loads, homeowners are likely to shift the start of EV charging time also for providing the lowest-price charging, as the cost if energy used for the EV can also be remarkable. The additional EV charging peak will be investigated in this paper and its effect to the existing network load power peak observed. Load data from existing residential network monitoring will be used as a basis for the comparison, where the time-of-use tariffs already have great impact. It will be shown that if the fixed-time tariff change is applied to domestic EV charging, this will result in rise of the short-time peak power demand peak in the network. For the distribution network operation, the uncontrolled EV charging could provide more relief than the simple two-tariff pricing case.

Load shifting in the existing distribution network and perspectives for EV charging-case study

Electricity markets demand that available transmission capacity should not produce bottlenecks and thereby limit the free competition. The transmission capacity of the system should be sufficient in all market situations and the existing system must be used as efficiently as possible. Still, reliability should not be endangered. Available transmission capacity is determined by network's physical properties. In practise this limit can not be reached because of deterministic N-1 security requirements. The N-1 planning method demands that the network should remain usable during any single fault. It is possible that even if the deterministic transmission capacity during the limiting fault is not high enough for the peak load, it could be sufficient if the fault occurs during a lower load level. It is also possible that fault statistics show that faults occur quite seldom during peak load. It is thereby possible that probabilistic planning shows that there is unused transmission capacity left in the transmission system. The aim of this paper is to propose a simple but practical probabilistic planning method to assess the economic risks of more efficient utilisation of existing networks.

https://ieeexplore.ieee.org/iel5/9135/28975/01304306.pdf

Transmission capacity assessment by using simple probabilistic planning

Is it advisable to replace ferraris based meters with electronic meters? The permanence of the electromechanical meters currently in use is often justified on the grounds of their long working life and low price. However, it is well known that they are highly sensitive to external conditions and that many factors can lead to miscalibration. This work attempts to clarify some key points in order to answer the previous question. It reviews the operating principles of energy meters. The behavior of watt-hour meters under nonsinusoidal conditions is also studied. The disturbances considered were harmonics, unbalance and main frequency variations.

Evaluation of Energy Meters’ Accuracy Based on a Power Quality Test Platform

Currently, there are two energy meters types installed: electromechanicals and electronics. The first ones are still the most frequent. However, new facilities tend to use electronics energy meters based on solid-state technology. Electromechanicals devices present characteristics already well known that allows us to measure only energy consumption. However, now the rules that manage the energy supply are totally new, there is a competitive electricity market. This way, detailed information on the energy consumption of each client is needed. In this point, electronic meters seem to be the best option to face the new challenges. This study will review the operating principles of solid-state energy meters. The behavior of some three phases models under nonsinusoidal conditions is studied. Experimental setup and test methodology are discussed as well.

/pdf/energy-meter-behaviour-under-non-sinusoidal-conditions-24xlmtmfhe.pdf

Matti Lehtonen

Papers

Load shifting in the existing distribution network and perspectives for EV charging-case study

Transmission capacity assessment by using simple probabilistic planning

Evaluation of Energy Meters’ Accuracy Based on a Power Quality Test Platform

Energy meter behaviour under non-sinusoidal conditions

Thermal analysis of non-isolated conventional PWM-based DC–DC converters with reliability consideration