The effect of solar-induced earth potentials on long-haul communication systems has been observed for many years, particularly on transatlantic cable systems. Direct current excursions of over 3,000 volts, observed at the power stations of these cable systems, have led to a design goal for earth current potentials in the range of 2-3 V/mi. There are numerous observations of large dc currents on continental long-haul communication lines, particularly during the "great" geomagnetic storm of 1940.1 The shutdown of the Bell System L-4 long-haul communication system at Plano, Illinois, during the August 4, 1972 geomagnetic storm has renewed the interest of the communications community in the study of geomagnetic-induced earth currents and their effects on communication systems.

Subject
Electric current, Voltage, Rocks, Power systems, Impedance, Outages, Waves, Surfaces, Electrical resistivity, Electric potential, Telluric current, Wind, Line current
© 1974 Association for Materials Protection and Performance (AMPP). All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means (electronic, mechanical, photocopying, recording, or otherwise) without the prior written permission of AMPP. Positions and opinions advanced in this work are those of the author(s) and not necessarily those of AMPP. Responsibility for the content of the work lies solely with the author(s).
1974
Association for Materials Protection and Performance (AMPP)
You do not currently have access to this content.