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PUBLISHER'S LETTER www.siliconchip.com.au Publisher & Editor-in-Chief Leo Simpson, B.Bus., FAICD Production Manager Greg Swain, B.Sc.(Hons.) Technical Staff John Clarke, B.E.(Elec.) Robert Flynn Ross Tester Rick Walters Reader Services Ann Jenkinson Advertising Enquiries Rick Winkler Phone (02) 9979 5644 Fax (02) 9979 6503 Regular Contributors Brendan Akhurst Rodney Champness Garry Cratt, VK2YBX Julian Edgar, Dip.T.(Sec.), B.Ed Mike Sheriff, B.Sc, VK2YFK Philip Watson, MIREE, VK2ZPW Bob Young SILICON CHIP is published 12 times a year by Silicon Chip Publications Pty Ltd. A.C.N. 003 205 490. All material copyright ©. No part of this publication may be reproduced without the written consent of the publisher. Printing: Macquarie Print, Dubbo, NSW. Distribution: Network Distribution Company. Subscription rates: $59 per year in Australia. For overseas rates, see the subscription page in this issue. Editorial & advertising offices: Unit 8, 101 Darley St, Mona Vale, NSW 2103. Postal address: PO Box 139, Collaroy Beach, NSW 2097. Phone (02) 9979 5644. Fax (02) 9979 6503. E-mail: silchip<at>siliconchip.com.au ISSN 1030-2662 and maximum * Recommended price only. 2  Silicon Chip Graphite bomb is too clever by half Just recently, in the conflict in the Balkans, we’ve heard of a new “graphite” bomb which has been used to temporarily disable the electrical grid. NATO spokespersons trumpeted the new bomb as a breakthrough, saying that they “have their fingers on the switch” and can take out the power at any time without doing permanent damage to the country’s infrastructure. Well, I just wonder about that. Supposedly, the new bomb is detonated above the high vol­tage switchyard for a power station or for a major substation. The bomb produces a dense cloud of graphite several hundred metres wide and this proceeds to short out all the high voltage switchgear in the area and the power station or substation is then off the air. No major damage is done but the effect is to immediately disable the power grid and hence prevent military activities that would otherwise occur. There seem to be several holes in this story. First, I can’t imagine how a dense graphite cloud propagated by a major explosion over a high voltage switchyard would only cause tempo­rary disablement. As far as I can see, it could well put the respective power station or substation completely out of commis­sion. Just imagine – everything in the yard, high voltage fuses, insulators, switchgear – all of it would have graphite forced into every nook and cranny. How would you clean it out? It would not be simply a matter of washing everything down with a high pressure hose; graphite is not easy stuff to clean off. No, the chances are that the graphite would well and truly permeate the surface of all insulators and switchgear. In fact, if all the fuses did not let go immediately, it is quite likely that all the graphite could provide the basis of a major fire. So it is possible that a great deal of the installation would have to be replaced, or if not, all of it would have to be painstakingly disassembled, cleaned and checked before it was put back into commission. In peacetime such a re-commissioning of a large switchyard would probably take months and cost millions of dollars. In a country on a wartime footing, it is not likely that such damaged switchyards could be properly re-commissioned until long after the cessation of hostilities. So NATO doesn’t simply have their finger “on the switch” – they’ve done a great deal more harm than that. It is also arguable whether they have stopped any military activities by killing the power. No, it seems to me that the graphite bomb is another exam­ple of technical overkill. Is this just technology for technolo­gies’ sake? Surely, if the desired result is to temporarily disable the grid, all that needs to be done is to take out a few of the high voltage transmission towers. You don’t need a hightech bomb for that. Leo Simpson