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A Tour through Networking and Grids

1. There is no need to dig trenches for cables (though tower construction must be taken into account). 2. Fiber optics has the largest information carrying capacity (easily into the Terabits per second).
3. The electronic bottleneck refers to the fact that with current fiber speeds nodal electronics is often slower than fiber speeds so that the information throughput bottleneck is in the nodes.
4. An advantage of geosynchronous satellites is that they are in one spot in the sky all the time so a fixed directional antenna on earth can be used. An advantage of Low Earth Orbit Satellites (LEOS) is that because of their much lower orbits than those of geosynchronous satellites, they have much smaller channel propagation delay.
5. The use of infrared light is technologically possible and systems have been built, but the use of infrared is not that popular.
6. Ad hoc transmission is usually over much smaller distances than satellite transmission (as small as tens of feet for ad hoc networks compared to hundreds or thousands of kilometers for satellite transmission).
7. Wireless sensor networks may be used for such applications as environmental monitoring, interconnecting engine components and connecting computer components (i.e. Bluetooth technology).
8. As a packet moves down a layered protocol stack (is transmitted) each layer may append information to the packet so that it is at its largest at the bottom of the stack (physical layer). At the receiver, as the packet moves up the stack, information may be extracted at each layer so the packet is at its smallest at the top (application) layer.
9. Packets carried on a virtual circuit arrive in the same order they were originally transmitted as they follow a single sequential path.
10. A communication between peer network layer entities moves down the stack at the transmitter to the physical layer, across the network to the destination and up the destination stack to the appropriate network layer entity.
11. One function of the data link layer is to manage communication over a single link between a pair of nodes. Also, encryption is sometimes done at the data link layer.
12. The network layer manages communication over a multiplicity of links and nodes whereas the data link manages communication over a single link between a pair of nodes. \
13. The transport layer is responsible for providing end to end communication over possibly unreliable sub-networks.
14. Thruput decreases in Ethernet under heavy loads because of the time wasted by collisions (in the CSMA versions of Ethernet).
15. With longer frames, as opposed to shorter frames, a bigger fraction of time is spent in useful transmission, as opposed to time spent in seizing the channel and collisions, so that utilization is higher.
16. A total of 3 × 3 = 9 symbols can be sent at once which is equivalent to 3 bits (23 = 8).
17. The use of unshielded twisted pair is a good thing because it is lightweight and relatively inexpensive.
18. If node A does not receive a Clear to Send message from node B it might try again to send a Request to Send or move to a different location and try again to send a RTS.
19. The use of a Clear to Send solves the hidden station problem in distributed wireless networks (some node over the radio horizon may try to transmit to node B at the same time as node A, causing a collision).
20. The amount of radio spectrum available for specific purposes is more limited than the equivalent bandwidth available on wired fiber.
21. If a network had to be constructed and taken down frequently, one would be better off using some combination of 802.11 WiFi and 802.15 Bluetooth technology as it is wireless, unlike standard Ethernet versions.
22. Using two 64 kps channels to carry 80 kps means that 128–80 or 48 kps of capacity is wasted.
23. In an ATM NNI connection 16 header bits are used for virtual channel identification (VCI) so that there are 216 or approximately 64 thousand virtual channels (per virtual path).
24. ATM assumes that data is transported over low error rate fiber optics so only the header is protected by error coding. If errors in the data field cannot be tolerated, then a higher level protocol can provide error coding.
25. The VPI and VCI fields in the ATM header, like the rest of the header, are protected by error coding which makes misrouting extremely rare.
26. The use of ATM technology leads to service class independent switches. If one needed different switches for each class of traffic one would have an intractable traffic prediction problem. Since it is almost impossible to accurately predict demand by service class into the future one might install too few or too many of each class of switch, leading to problems in either providing inadequate capacity or over-investing in network facilities.
27. One application where it is critical to deliver data quickly is the transmission of stock prices. Also real time applications such as voice or video require packets be delivered within certain time limits (bounds).
28. A contract for an ATM session is difficult to define because there are so many quality of service parameters that could be used. Thus there are many possible contracts with many possible pricing options.
29. A T1 line has a data rate of approximately 1.5 Mbps. A SONET OC-3 channel has a data rate of approximately 155Mbps.
30. Each byte entry in a SONET OC-1 frame has an equivalent data rate of 64 kbps. Thus to carry 1 Mbps one needs 1 Mbps/64 kbps or 16 entries of the 87 × 9 = 783 entries in the frame. Note that if the question is how many frames are needed to carry 1 Mbyte, not 1 Mbps, the answer is 1,000,000/783 or 1278 frames (neglecting path overhead).
31. A SONET add/drop multiplexer is a device that allows signals to be tapped off of and inserted onto a fiber.
32. In SONET protection fibers are backup fibers that can be brought into use if the service fibers that normally carry traffic do not function.
33. The line protocol layer in SONET is most similar to the data link layer in the OSI protocol stack. 34. More virtual paths are allowed on an ATM NNI link than a UNI link as the NNI link is like a trunk that is likely to carry much more traffic than a UNI network access link.
35. Transmitting in one byte of a SONET table has an effective data rate of 64 kbps. This is the standard data rate for an uncompressed digital telephone channel.
36. The approximate data rate of OC-3072 is 3072 times 51 Mbps (the OC-1 rate) or approximately 160 Gbps.
37. Each OC-192 channel has a data rate of approximately 10 Gbps so approximately 76 WDM OC-192 channels are needed to carry 760 Gbps.
38. The technology of WDM allows fiber already put in the ground (at great expense) to be upgraded through a simple replacement of transmitters and receivers to carry a much larger amount of traffic. 39. The basic idea behind grid computing is to allow a user to access a large distributed network of powerful computers and storage devices from anywhere on earth to carry out substantial computations of a scientific, economic or other nature. It is actually an old concept that predates the use of the word “grid”.
40. To partake in grid computing a computer installation needs to be more open to use to outside users and entities, something not that well tolerated under old policies.
41. In the past when the (computer) resource owner was the key person, operations were optimized for high throughput. Making the user the key person necessitates a new set of requirements.

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ger in my front yard. This book is another screen, another lens trained on those events.It tells stories about two villages separated by time,connected by proximity,and united by the challenges of maintaining a community under duress. 
          The story of one village presents an insider’s view of a natural disaster, describing the destruction of the electric grid in January 1998 and the emergence of a community that filled the resulting void.This story begins with moments in the lives of people in the village of Potsdam, New York people such as myself,my family,my neighbors,townspeople,local officials, and relief workers and expands to cover the breadth of the disaster. The book concludes with a timeline of events that traces the disaster from the storm’s origins in the Gulf of Mexico to the lethal flooding it caused as it moved slowly up the eastern seaboard to the icy devastation it brought to the Northeast. The story of the other village begins nearly two hundred years before the ice storm in a place called Louisville Landing, about twenty miles from Potsdam on the border between the United States and Canada.This narrative provides a glimpse of what it took to build the kind of grids that made this nation, the grids that connect us to one another. It is told through the experiences of some of the people who sacrificed the most to build them.

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This chapter briefly discusses the growth of complex electrical power networks. It introduces the lack of controllability of the active- and reactive-power flows in energized networks. (These flows tend to diffuse in the network, depending primarily on the impedance of power lines.) This chapter also describes the conventional controlled systems, such as automatic governor control and excitation control employed at generating stations. Transformer tap-changer control is another control feature generally available in transmission networks. Arising from the transformer combinations and the use of on-load tap changers, phase-shifting transformers are realized, which are primarily used to mitigate circulating power on network tie-lines.
          This introduction and the recognition of limited controllability provide the basis for introducing the concept of the flexible ac transmission system (FACTS). Since newly developed FACTS devices rely on the advances made in semiconductor components and the resulting power-electronic devices, these, too, are introduced.
        This chapter also introduces the basic operating principles of new FACTS devices. (These principles are fully discussed in later chapters of this book.) Finally, the chapter presents a brief commentary on emerging deregulation, competition, and open access in power utilities. In that context, the value of FACTS devices for emerging transmission companies is identified.

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The wireless transfer of energy as scalar wave radiation goes back on Nikola Tesla. From him originated the patent No. 649.621 on 15.5.1900: Apparatus for transmission of Electrical Energy. Unfortunately his equipment was extremely large and expensive, so that no copies had been provided and the ingenious technology could extract itself from the field of vision and the consciousness of the public. Many sceptics however are to be convinced only, if they have their own copy, at which they personally can make measurements and experiments. A new technology will only become public and can assert itself if it is carried beyond the scientific facilities and education centres into the public. 
        The lost believed technology is taken up again with the kit. By using a modern waveform generator in place of a spark gap generator, with an operating voltage of few volts in stead of 600 kilovolts a miniaturization of the device succeeded, at which all characteristics indicated by Tesla and still some more can be introduced and examined experimentally. Today, nearly 100 years later a scalar wave transmission device fits into a suitcase and is purchasable for everyone. 
       All assembly groups and component parts necessary for the experiments are included in delivery, as well as the aluminium suitcase, which is used as shielding cage. Thus a high degree of reproducibility is guaranteed. The demo kit is particularly suitable for nontechnicians to open them the possibility of a successful execution of the experiment. For technicians and hobbyists a more extensive experimentation kit is offered. It is particularly important for comparison purposes that everyone does work with the same generator, because the empiric reports will be published in an anthology, which should encourage other experimentators to reproduce some of them.

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THE art of electrical power transmission has changed but little in the past two years, since the fourth edition of this work went to press. There have been very many plants installed, few of them at all sensational in magnitude, voltage, or distance of transmission. The great bulk of such work is now rather commonplace. The upper limit of voltage has already risen to nearly 70,000 volts, and the next few years will assuredly see a very material increase over this figure. A few new pieces of apparatus have been recently brought into use, which have been noted in their appropriate places. Perhaps the most considerable impending changes are those in the resources of electric lighting which affect only those transmission systems which do their own distribution. These changes, however, bid fair to be on a very large scale and of very striking character within the next few years.

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This book presents a method of adapting the traditional probabilistic safety analysis (PSA) to the security analysis of a power system. The book proposes are liability model for a power system, where the possible failures of substation operations after grid faults are analysed and their impact on the power system dynamics and security is taken into account. The book presents the method in such a way that the reader is guided and equipped to build up a similar model. This reliability approach is suitable and applicable to real transmission grids, which can have hundreds of substations and lines. 
      In the reliability analysis of transmission systems, the basic phenomena and reliability problems are at the system level. The analysis of the local perspective, for example the outages of single components, is not adequate to capture the whole picture. So far, there have not been systematic methods that would combine local and system level issues in a similar way as this book presents. The method adapts the traditional probabilistic safety analysis (PSA) to the security analysis of a power system and includes the simulation of grid dynamics after grid faults and component failures in the modelling. This combination of different (traditional) tools enables a systematic security analysis where the connection of the failures ofsingle devices and the system level consequences, for example a system breakdown, is possible.

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The generation, delivery, and utilization of electric power and energy remain one of the most challenging and exciting fields of electrical engineering. The astounding technological developments of our age are highly dependent upon a safe, reliable, and economic supply of electric power. The objective of Electric Power Engineering Handbook, 2nd Edition is to provide a contemporary overview of this farreaching field as well as to be a useful guide and educational resource for its study. It is intended to define electric power engineering by bringing together the core of knowledge from all of the many topics encompassed by the field. The chapters are written primarily for the electric power engineering professional who is seeking factual information, and secondarily for the professional from other engineering disciplines who wants an overview of the entire field or specific information on one aspect of it. 
          The handbook is published in five volumes. Each is organized into topical sections and chapters in an attempt to provide comprehensive coverage of the generation, transformation, transmission, distribution, and utilization of electric power and energy as well as the modeling, analysis, planning, design, monitoring, and control of electric power systems. The individual chapters are different from most technical publications. They are not journal-type chapters nor are they textbook in nature. They are intended to be tutorials or overviews providing ready access to needed information while at the same time providing sufficient references to more in-depth coverage of the topic. This work is a member of the Electrical Engineering Handbook Series published by CRC Press. Since its inception in 1993, this series has been dedicated to the concept that when readers refer to a handbook on a particular topic they should be able to find what they need to know about the subject most of the time. This has indeed been the goal of this handbook.
           This volume of the handbook is devoted to the subjects of electric power generation by both conventional and nonconventional methods, transmission systems, distribution systems, power utilization, and power quality. If your particular topic of interest is not included in this list, please refer to the list of companion volumes seen at the beginning of this book. 
           In reading the individual chapters of this handbook, I have been most favorably impressed by how well the authors have accomplished the goals that were set. Their contributions are, of course, most key to the success of the work. I gratefully acknowledge their outstanding efforts. Likewise, the expertise and dedication of the editorial board and section editors have been critical in making this handbook possible. To all of them I express my profound thanks. I also wish to thank the personnel at Taylor & Francis who have been involved in the production of this book, with a special word of thanks to Nora Konopka, Allison Shatkin, and Jessica Vakili. Their patience and perseverance have made this task most pleasant.

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Modern economies are becoming increasingly dependent on reliable and secure electricity services. The substantial supply disruptions that struck North America and Europe during 2003 clearly demonstrated the fundamental importance of transmission networks for the efficient and secure operation of electricity markets and highlighted their vulnerability to transmission network failures. While large blackouts are by no means a new phenomenon and have happened in the past before electricity reform, these disruptions created considerable public concern, with some claims that electricity reform had reduced electricity system reliability. Growing public sensitivity to supply disruptions reflects the increasing dependence of modern economies on reliable and efficient electricity supplies, and adds to the pressure on governments to effectively address reliability issues. 
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This study covers the world outlook for electric bulk power transmission and control across more than 200 countries. For each year reported, estimates are given for the latent demand, or potential industry earnings (P.I.E.), for the country in question (in millions of U.S. dollars), the percent share the country is of the region and of the globe. These comparative benchmarks allow the reader to quickly gauge a country vis-à-vis others. Using econometric models which project fundamental economic dynamics within each country and across countries, latent demand estimates are created. This report does not discuss the specific players in the market serving the latent demand, nor specific details at the product level. The study also does not consider short-term cyclicalities that might affect realized sales. The study, therefore, is strategic in nature, taking an aggregate and long-run view, irrespective of the players or products involved. 
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The variability of power output exhibited by many renewable electricity sources represents something of a challenge to maintaining secure supplies in the integrated electricity systems of industrialized countries – especially if, as widely anticipated, the contribution of renewables to national grids rises to very substantial levels. But is this a major – or even an insuperable – challenge, or one that is readily amenable to solution? This is the key question this book attempts to address. It also raises a host of other important issues. 

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In 1968,the edison Electric Institute published the EHV Transmission Line Reference Book,a design handbook for the electric utilities of the United States.This book was based on the results of many year of research sponsored by General Electric and the utilities industry at what then was Project EHV in Pittsfield,Massachusetts.This research evolved around the design and development of EHV transmission from 345 KV to 735 KV,the latter being the exected ,maximum ac transmission voltage in North America for several years to come. 

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THIS book is compiled from a series of lectures intended to bridge the theoretical instructions given in the ordinary university education, and the practical problems confronted in commercial engineering. The sequence of the various phenomena discussed is not, therefore, so logical as would be the case if a book on electrical phenomena had been attempted. Jt is hoped, however, that the arrangement will prove of practical help. Since many of the questions pertaining to practical engineering cannot be answered by a strictly theoretical calculation, without going into too complex mathematics, some approximate equations have been given, sufficiently accurate for most practical purposes. 

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