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2S10th International Zurich Symposium

and Technical Exhibition on Electromagnetic CompatibilityMarch 9 -11,1993

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EMC Zurich '93

Honorary Patron:

Mr.F.Locher,Berne

Honorary Chairman:

Prof. Dr. T. Dvorak, Stallikon

Under the auspices of:

Mr. F. Rosenberg, Director-General of the Swiss PTT Telecom, Berne

Sponsor:

IEEESwitzerlandChapteron ElectromagneticCompatibility

Organized by:

Communication Technology Laboratory of the Swiss Federal Institute of Technology Zurich

Cooperating: ..

Swiss Federal Institute of Technology Zurich (ETHZ), Swiss Electrotechnical Association(SEV/ASE), IEEE Switzerland Section, Convention of the National Societies of ElectricalEngineers of W. Europe (EUREL), European Broadcasting Union (EBU), Association ofPolish Electrical Engineers (SEP), International Telecommunication Union (ITU), IEEEElectromagnetic Compatibility Society, International Union of Radio Science (URSI).

Organizing Committee:

Prof. Dr. P. Leuthold, Zurich (Symposium President); Prof. Dr. W. Zaengl, Zurich; Prof. Dr.F. L. Stumpers, Eindhoven (Vice-Presidents); Dr. G. Meyer, Zurich (SymposiumChairman); Prof. Dr. C. R. Paul, Lexington (Technical Program Chairman); Dr. B.Szentkuti, Berne (Technical Program Vice Chairman); H. A. Kunz, Luterbach (Exhibition);Dr. U. Kaiser,Fribourg;Dr. D. Hansen,Berikon(Publicity);Prof.Dr.M. lanoz, Lausanne(Joint Events); W. Blumer, Zurich (Publications); Dr. G. Klaus Zurich; R. Danieli, Zurich;Mrs. B. Howald, Zurich; J. 0rum, Zurich; C. Schmid, Zurich (Local Arrangements); T.Meier, Zurich (Treasurer); Mrs. E. Danieli, Zug (Social Program).

Technical Program Committee:

Chairman: Prof. Dr. C. R. Paul

Prof. Dr. M. Darnell, Hull; Prof. Dr. P. Degauque, Villeneuve-d'Ascq; Dr. J. J. Goedbloed,Eindhoven; Prof. Dr. W. Hadrian, Wien; Prof. Dr. M. Hayakawa, Tokyo; Dr. G. Klaus,Zurich; Dr. G. Meyer, Zurich; Prof. Dr. E. Nano, Turin: Prof. Dr. H. Singer, Hamburg; Dr. A.D. Spaulding, Boulder; Dr. B. Szentkuti, Berne.

Advisory Committee:

Prof. Dr. D. J. Bern, Wroclaw; Prof. Dr. M. Darnell, Hull; Dr. G. K. Deb, Bangalore; Prof. Dr.M. lanoz, Lausanne (Swiss National Committee of the URSI); Dr. J. Heyner, Zurich (SEV IASE); H. R. Hofmann, Naperville I H. K. Mertel, San Diego (IEEE EMCS); R. C. Kirby,Geneva (ITU); W. Moron, Wroclaw (SEP); Dr. D. Profos, Solothurn (IEEE SwitzerlandSection); Ch. Scherrer, Berne (BAUEM); Prof. Dr. H. Schmeer, Neubiberg; G. T. Waters,Geneva (EBU); D. R. J. White, Gainesville; Prof. T. Yoshino, Tokyo.

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POWER AND DATA LINE TRANSIENrS

Fran~is D. MartzloffNationalInstituteof Standardsand Technology

GaithersburgMD 20899USA

It is a great pleasure to introduce the authorscontributing to this session on Power and DaJalineTransiems, a session that will bring new ideas, orbring changes to old ideas, to the shared body ofknowledgeon this subject. With the ever-increasingdependency of our society on electronic devices, theneed for ensuring their electromagnetic compatibilityis also increasing.

The common wisdom, or stereotype description ofthis trend has been to call it 'exponential growth'.Nevertheless, without indulging into easy and riskyforecasts, we can expect that this trend will continue.The European Communities Council Directive onelectromagneticcompatibilityrecognizesthis situationand will require from all interested parties a betterunderstanding of the electromagnetic environment inwhich these electronic devices operate.

With that purpose in mind, this session gathersexperts on both sides of the table: the authors who arebringing their contributions, and the participants whowill focus on the subject during the session and takehome the new ideas. This written record will serve

as a reminder of our proceedings to the fortunate whoparticipated, and at least serve as a valuable source ofreferences to those who were unable to attend.

The first paper, by Dischinger, Koehler andScluurly. deals with the need for electromagneticcompatibility not only of general user's equipment,but also of the measuring equipment used to assessthe electromagnetic environment at a specific location.Indeed, if this instrumentation were susceptible todisturbances, then how could we depend on themeasurements results when prescribing realisticimmunity levels or mitigation steps for the end-userequipment? By combining the measurements andcomputer modelling, the authors bring us addedconfidence in their conclusions, and important data oncharacterizing the harsh electromagnetic environmentof high-voltage substations.

The secondpaper, by Richman, addressesthe issueof wearing out a test specimen through the process ofimmunity testing, an issue that is tating renewedimportance as we witness the promulgation of morestressful test programs. Thus, it is important that weclearly understand the implications of these testprograms on devices such as metal-oxide varistorsthat have an acknowledged limitation on the numberof surges that can be applied. The purpose of a testprogram is to demonstrate equipment immunity, aprocess that can require the applicationof many moresurges than what we can expect the equipment toencounter in its actual service life.

The third paper, by Standler, presents a review ofpresent knowledge on the occurrence of neutral-earthsurge voltages. This paper is a welcomecontributionto a subject where field data have been scarce, andcontroversies have erupted. The situation is mademore difficult by the differences existing in theneutral-earth bonding practices among variouscountries. By turning to modelingof the branchcircuit behavior as a transmission line, the author isable to demonstrate not only that surges do occur inthe neutral-earth mode, but also that some of thecurrent perceptions on their amplitude and frequencyneed to be revisited.

The fourth paper, by RichLer, Schmidt and Tanner isa contribution to the growing realization that surgeprotection performed by cascading devices requires acoordinated approach. The concept of a descendingstaircase of overvoltages within a building, initiallyproposedby IEC664, is aboutto be reconsideredbyseveral technical committees of the IEC. In theirpaper, the authors address primarily the electro-magnetic pulse threat. The concept of a coordinatedapproach based on a diversity of complementarydevice performances, and the need to revisit some ofthe earlier assumptions, also applies to the broadrange of surge waveforms occurring in the electro-magnetic environment.

The fifth paper. by Brocke, Goehlsch, and Noack, isa timely contribution to the growing body of data oncomputer modelling of complex surge-protectivedevices, used as a single protection or, once again, ina multi-step scheme. The authors present severalmodels for computing the behavior of varistors overtheir dynamic range, as well as the behavior of thefast gaps that may be used in conjunction with othernonlinear devices. They call attention to the issues ofparallel connection and energy sharing, and point outthe side effects of the action of a gap on the protectedequipment, on the gap itself, and on the power systeminvolved in the surge event.

The sixth paper, by Martzloff and Samotyj, inight beseen as a transition between the subjects of power-lineand data-line transient protection. In fact, the purposeof the paper is to call attention to a situation that isonly beginning to receive appropriate consideration.For multi-port electronic devices, transients occurringin power lines can no longer be treated separatelyfrom transients occurring in data lines and vice-versa.The term coordinated protection, used in discussingthe previous papers where multiple devices areapplied on the power port, takes on the differentmeaning of coordination between two different ports,the power port and the communications port.

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The seventh paper, by Wolf. Plath and terHaseborg,brings the session to a shift from power lineconsiderations to the domain of RF signals. Bycomputations and measurements, the authors show thedilemma of connecting nonlinear devices forprotection of the signal-processing equipment againsttransients, while avoiding the degradation of thenormal signal by the secondary effects of otheroperating regions of a diode. The challenge is evengreater in high frequency circuits, compared to thecase of power line protection where the normal'signal' is the low-frequency power supply, far awayfrom the transients in the electromagnetic spectrum.

Thus, this session will take you along a non-randomwalk in the domain of power line and data linetransients. It is interesting to note that all theseindependent contributions can nevertheless be linkedby shared concerns on better understanding of thebasic electromagnetic threat - the "environment -as well as the behavior of the devices proposed tomitigate this threat. In conclusion then, on behalf ofthe Symposium organizers and especially thoseinvolved in this session, we thank the authors fortheir contributions as well as the participants for theirdiscussions, and look forward to a very stimulatingexperience.