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                          of the IPTL SC Meeting in Sao Paulo, Brazil, November 24, 2005

                                         International Project
                  Electromagnetic Radiation from Lightning to Tall Structures (IPTL)
                                Thursday, November 24, 2005
                                     Sao Paulo, Brazil
                                Hotel Caesar Business Sao Paulo – Faria Lima
                                           17:00 pm to 19:20 pm

             At the SC Meeting there were present 20 participants from 11 countries including:
SC Members
Farhad RACHIDI                  Ecole Polytechnique Federale de Lausanne                   Switzerland
Volodymyr SHOSTAK               Nat. Technic. Univ. of Ukraine “Kyiv Polytech. Inst.”      Ukraine
Wolfgang SCHULZ                 Austrian Lightning Detection and Inform. System            Austria
Ali M. HUSSEIN                  Ryerson University and University of Toronto               Canada
Fridolin HEIDLER                Federal Armed Force University, Munich                     Germany
Carlo Alberto NUCCI             University of Bologna                                      Italy
Vlad RAKOV                      University of Florida                                      USA

Members of Participating Organizations
Gerhard DIENDORFER              Austrian Lightning Detection and Inform. System            Austria
Alexandre PIANTINI              IEE/USP (University of Sao Paulo)                          Brazil
Silverio VISACRO                Lightning Research Center (LRC)                            Brazil
William A. CHISHOLM             Kinectrics                                                 Canada
Yoshihiro BABA                  Doshisha University, Kyoto                                 Japan
Christian BOUQUEGNEAU           Faculte Polytechnique de Mons                              Belgium
Jinliang HE                     Tsinghua University                                        China
Patricio Munoz ROJAS            LACTEC                                                     Brazil
M. BALLAROTTI                   INPE                                                       Brazil
Marina BERNARDI                 CESI                                                       Italy
Cinzia A. ROVELLI               CESI                                                       Italy
Ken CUMMINS                     Vaisala / University of Arizona                            USA
Stan GRZYBOWSKI                 Mississippi State University (MSU)                         USA

             1. Opening Remarks

            Farhad Rachidi, Vice-Chairman of the Steering Committee (SC), opened the meeting.
     He expressed apologies of those not able to attend the Meeting (W. Janischewskyj,            T.
     Shindo, J.-S. Chang, R. Thottappillil) and forwarded salute to participants from W.
     Janischewskyj (Chairman of the SC),
            Farhad Rachidi expressed appreciation to all Brazilian colleagues for the nice
     Symposium and hospitality, and personally to Alexandre Piantini for assistance in arranging the
     SC Meeting.
                     of the IPTL SC Meeting in Sao Paulo, Brazil, November 24, 2005

       2. Self-introduction of those present

       All participants have introduced themselves.

       3. Acceptance of the Agenda

         F. Rachidi suggested changes in the order of topics in preliminary Proposed Agenda:
first to perform the Administrative session (reports, next Workshop and SC Meeting), then –
Discussion session. The modified Agenda was accepted.

       4. Reports from Participating Countries

        After presentation of reports on last year’s activity, financial support and plans in
relation to tasks of the International Project (IP), it was agreed that within a few weeks after the
SC Meeting the representatives of each country will provide files of their brief reports/
summaries by e-mail to the SC Secretariat (e-mail address to be used is linked at Project
website: http://emcwww.epfl.ch/iplt/). Some reports were already obtained and taken into
account during preparation of this Minutes Draft. They are posted at mentioned IPTL website.
Other reports/comments are expected and will be added later.

      Austria (reported by Gerhard Diendorfer)
      Austrian group includes the Austrian Lightning Detection and Information System
(ALDIS), Department of the Austrian Electrotechnical Association (OVE) in Vienna (Gerhard
Diendorfer, Wolfgang Schulz), and Technical University Vienna (M. Mair, H. Pichler).
      Gerhard reported on some modifications made at the Gaisberg tower site and on plans.
Some points are:
       Measurements of lightning current at the tower top.
       Measurements of nearby (200 meter) electromagnetic fields of flashes to the tower
           using direct triggering from current at the tower. 24-hours operating system.
       Only 1(st?) strike already got (?).
       Ground-wire at the bottom of the tower – measurements of current distribution
           along the wire. Current sensors – up to 60 m with the step of 20 m.
       Plans for development of EM field measurements – previous system + station at 1
           km distance; triggering through the Internet (~10 s; details?).

        Germany (reported by Fridolin Heidler)
        It is planned to resume the lightning current activities at the Peissenberg tower as soon
as possible. The status is the following:
        The Peissenberg tower belongs to a sub-company of the German telecommunication
             company. The preparations for the measurement activities will start as soon as the
             contract with this company is signed. It is expected that this will happen within the
             next months.
             At the tower top, a current shunt will be installed with an upper cut-off frequency
             of 50 MHz and a di/dt – Sensor with an upper cut-off frequency of more than 1
             GHz. At the tower base two magnetic field sensors will be installed in order to
             measure the current and the current derivatives there via the magnetic field. The
                    of the IPTL SC Meeting in Sao Paulo, Brazil, November 24, 2005
           measured signals will be transferred to a measuring cabin using coaxial cables. The
           measuring cabin is located inside the tower near ground level.
          The currents (at the top and at the bottom) will be measured by 14-bit digitizers
           with 10-ns sample interval and a duration up to 2,56 s. The currents <derivatives?>
           (at the top and at the bottom) will be measured by 12-bit Digitizers with 5 ns sample
           interval and a duration up to 1,28 s.
          A GPS-clock will be used for the time stamp.
          The program LABVIEW will be used for the data acquisition.
          They decided to use for current measurements a passive type system due to service
           difficulties (current transformer, regular cable 160-m long, 50 Ohm). Grounding
           should be at one point. Sensors – like at Gaisberg and Florida Center.
          Field measurements – not yet, will be next phase.

        USA (reported by Vlad Rakov)
        Vlad Rakov reported that lightning studies were continued at the University of Florida
(UF) and at Camp Blanding. Some of the researches are performed in cooperation with several
international partners and visitors. Some reported points are following:
        More similarities are found between rocket-triggered and tall structure lightning (?).
        During last summer there were triggered and recorded 11 flashes. Measurements
            included RS speed and housing tests.
        Also they have measured: I, di/dt, E, dE/dt, H, dH/dt; X-rays (with UofF).
        Cooperation with Japanese visitor Yoshihiro Baba resulted in 6 papers, including on
            lightning to tall structures.
       UF publications can be found on the following site: http://www.lightning.ece.ufl.edu/.

       Japan (reported by Yoshihiro Baba)
       Yoshihiro Baba briefly reported on activities of Japanese Group headed by Takatoshi
Shindo. He reported shortly on works by Takatoshi Shindo, Masaru Ishii, Shigeru Yokoyama
and their collaborators. Some points mentioned are following:
        Growing interest to tall structure lightning studies ...
        Attachment point ...
        Significant attenuation of the current wave on its return way from tower’s bottom to
            top (and not too much attenuation on its initial way from the top to bottom). Tower
            – a non-uniform transmission line…

       Canada (reported by Ali M. Hussein)
       First, Ali Hussein forwarded the salute message from Prof. Wasyl Janischewskyj, Chair
of SC, and then presented his Report to participants of the Meeting.
       Report was made on behalf of the Canadian Group consisting of W. Janischewskyj –
University of Toronto, A.M. Hussein – Ryerson University and University of Toronto, and J.S.
Chang – McMaster University (Hamilton, Ontario).
       Some points mentioned are following:
        No ALPS this year in Toronto.
        Collaboration with the EPFL. During the 2005 Lightning Season, Davide Pavanello,
            a doctoral candidate from the Swiss Federal Institute of Technology in Lausanne,
            working with Professor Farhad Rachidi, stayed at the University of Toronto for …
            months and participated in the CN Tower Lightning Project… Distances…
                    of the IPTL SC Meeting in Sao Paulo, Brazil, November 24, 2005
           Dr. Emanuel Petrache, a recent Ph.D. graduate of Professor Farhad Rachidi, worked
            at the University of Toronto with Professor Wasyl Janischewskyj from September
            2004 to August 2005 as a Postdoctoral Fellow. The topic of his research project is
            entitled "Analysis of Lightning Current Dispersion in Telecommunication Towers".
            He also performed some experimental tests on CN Tower grounding with Prof. W.
         Corrected some problems with E and H sensors. Still calibration is needed.
         GPS was installed for I, E, H measurements and for video recording. Not yet for
            high-speed (HS) camera.
         Searching for new HS camera.
         Aug. 19, 2005 – many records. Problems with current records. GPS, NLDN. Flashes
            – video recording, 100 % effectiveness; for strokes – lesser effectiveness.
         Priority of interest to NALDN evaluation … Looking for sensor (LPATS). They
            will study trajectory effects upon location accuracy. Predicted currents (LDN) are
            significantly different from measured at the CNT. Doubts on calibration of (old)
            Rogowski coil; will test it in the lab during the winter.
         Publications.
        G. Diendorfer: Do you always have a success in getting video (VHS) records? At
Gaisberg in most cases it is recorded just a general illumination of clouds, not the lightning
channel above the tower.
        A. Hussein: Usually they have successful records of the channel. Some strokes are
missed, but other strokes of flashes are recorded.
        G. Diendorfer: What is the relation of current values obtained from LDN and tower
        A. Hussein: For the same events, currents measured at the tower are noticeably lower
that those obtained from LDN.
        G. Diendorfer: Our observations for short tower (at Gaisberg) do not show such a big
difference in current values.
        K. Cummins had confirmed that point based on studies for <tall and> short structures.

        Ukraine (reported by Volodymyr Shostak)
        Ukrainian Group (Volodymyr Shostak, Kyiv Polytechnic Institute) is continuing
collaboration with Canadian and Swiss Groups.
        Some points mentioned:
         Continued cooperation with the LSG Group in Toronto and EPFL Group: analysis
            of observed data, experimental set-ups, simulation, publications, etc.
         Development of theoretical estimations of lightning surges coming from MV
            distribution lines (three-wire approach, influence of corona and attenuation of
            surges due to finite ground conductivity). Interest in considering in analysis the
            influence of nearby (tall) structures.
         On request of LP companies, suggestions on the procedure for tests of active
            lightning protection devices are made.
         On request of LP companies in Ukraine, a preliminary work is continued for
            development of Ukrainian standards on LP.
        The supports from Canadian and Swiss Groups for conference participation, as well as a
     support from COST P18 Action for participation in SC Meeting are very much appreciated.
                     of the IPTL SC Meeting in Sao Paulo, Brazil, November 24, 2005

       Brazil (reported by Alexandre Piantini and Silverio Visacro)
       Alexandre Piantini (Univ. of Sao Paulo)
       Latest results on lightning studies of Brazilian Group were presented at SIPDA.
       Some points mentioned at the meeting:
        Tower, … m; current shunt at the bottom; only 1 event is recorded during 2 years of
          system operation.
        Line close to tower; arresters; recorders of overvoltages.
        Simulation by using LIOV.
       Silverio Visacro (Lightning Research Center, Belo Horizonte, Brazil)
       Copies of papers prepared by LRC scientists were kindly distributed to participants.
       Some points mentioned in report:
        Bad news – no reliable data for 1 year (system is not operating because of the
          reconstruction at the tower).
        Good news – a new shunt designed and installed at the tower’s base; also – a Pearson
          Coil. Long time intervals measurements (…).
        Camera… Strike … Two lines (10 m apart, 1 km long) close to the tower.
        Experimental TLs in mountains, not far from C. Tower. Current measurements at
          both sides of TL.
        Cooperation with Vlad Mazur. Field mills. Looking for correlation between fields
          and upward flashes (?); “failed” strikes.
        Cooperation with Vernon Cooray – field measurements close to <Tower> Station
          (100 m, 1 km, 5 km, …).
        Studies at various communication towers around the country – 6 own-designed
          devices are installed for recording currents through field measurements close to

        Switzerland and Italy (reported by Farhad Rachidi)
        This Report is made on behalf of the Swiss Group consisting of Farhad Rachidi (Swiss
Federal Institute of Technology) and Marcos Rubinstein (University of Applied Sciences), and
Italian Group consisting of Carlo Alberto Nucci (University of Bologna).
        The following points were mentioned:
         Close collaboration is continued with Canadian, Italian, Swedish, Austrian and USA
         During summer 2005, the Swiss-Canadian group made simultaneous measurements
           of return stroke current and the corresponding electric and magnetic fields at different
           distances. New station was added 50 km away from the CNT (at …; field wave
           propagation is along the Lake Ontario surface).
         Davide Pavanello. Data are under analysis.
         Ken Cummins. Data from NALDN for comparison to simultaneous CNT
         Emilio Petrache. Grounding, current distribution (CNT test and simulation).
         New project within COST Action (Toronto. Austria-Gaisberg – field measurements
           at short ranges, ~50 m).
         Swiss tower – still searching for location and support.
         Design and tests of field sensor (EPFL,University of Applied Sciences, Switzerland) .
                     of the IPTL SC Meeting in Sao Paulo, Brazil, November 24, 2005
        Ken Cummins reported on previous studies of CG strikes using NLDN and
videocameras’ observations... Also his preliminary look at <CNT related?> NALDN data shows
that most CG strikes are observed 3-15 km away from the tower... Stratiform clouds ..., charges;

        5. Date and Place of next International Workshop and next SC Meeting
        F. Rachidi informed participants that next COST P18 Workshop will take place in
association with EGU (European Geosciences Union) XXXI General Assembly in Vienna,
Austria (April 2-7, 2006). [Web-site: http://meetings.copernicus.org/egu2006/; deadline for EGU
Abstracts – January 13, 2006]. To save travel funds, Farhad suggested arranging of the IPLT
Workshop 2006 also at the same time and location (Vienna). At Kanazawa (ICLP’2006) he
suggested to have a SC Meeting of IPLT to communicate more closely with Japanese and
Brazilian partners.
        Gathering have discussed this suggestion and accepted it. It was also agreed that
participants of the Workshop should prepare a 1-page Abstract (the deadline will be announced
later) and that the Workshop will have format of a Round-Table Discussion.
        Coordination with EGU, need for EGU Abstracts, and determination of exact date, time
and place of Workshop will be adjusted early in January with the assistance of Austrian
colleagues (Gerhard Diendorfer).
        Further details will be discussed and distributed by e-mail.

         6. Discussion/suggestions on cooperation
         G. Diendorfer: Suggested to clarify the meaning of “Calibration of LDN using towers”:
1 /Subsequent strokes? Upward/downward flashes? Positive/negative? etc.
         S. Visacro: Downward, using short instrumented towers; with registration units
equipped by GPS timing. They have designed recorders for non-instrumented towers and
installed them at several sites. Could be applied for triggered lightning. Registration: whole
current waveforms (a few milliseconds); selection of strikes related only to towers.
         B. Chisholm: + sites in USA?
         K. Cummins: “+” and “–“ - bi-polar … Some funds (like 3 %) could be requested from
LDN owners for studies on calibration purposes.
         V. Rakov: Natural lightning recorded at Camp Blanding (1 km2 area) also could be used
for LDN calibration (E-, H-sensors, video, GPS timing, …). Including 1st strokes and “+”.
         K. Cummins: A lot of tower-RS models. It is a need in a group effort, to consolidate and
get reliable acceptable model for engineering applications. + Lightning Physics + Processes in
branches of the 1st stroke…
         M. Bernardi: Suggested to develop cooperation on collection and analysis of results on
current measurements at different sites around the world. How much of them could be used, in
what way? She requested from participants to send available important papers.
         Marina was asked to make a first approach, to prepare questionnaire and to distribute it
among participants.
         C.A. Nucci: Underlined the problem of redundancy of information. Important papers on
tall structure lightning observations could be placed at the web-site (with access through a pw).
Participants could upload papers. Need in different data related to power lines, substations;
studies at instrumented towers; data of Berger; need of a new reliable data for standards and
different applications (including EMC, etc.).
         F. Rachidi: We can request from all groups to send only 2-3 papers with updated results
or also a summary.
                     of the IPTL SC Meeting in Sao Paulo, Brazil, November 24, 2005
        S. Visacro: It is important to get data on effect of structure height, to know exact
conditions of observations.
        K. Cummins: …<supported these points>.
        V. Rakov: Was asked to circle the main topics for these cooperative studies. It could be:
        - Top and bottom current measurements;
        - <Cumulative> current distributions (in dependence on object height);
        - Enhancement of the field.
        These topics were accepted by gathering.
        F. Rachidi and C.A. Nucci: Asked every group to send/download own and other
authors’ papers (in pdf), and summaries. M. Bernardi was asked to prepare a preliminary list of
related publications. The information for downloading will be distributed by Marina.
        G. Diendorfer: Raised a question of selection topic(s) for the next Workshop’2006.
        In discussion it was first suggested:
        - Measurements and analysis of tall structure lightning parameters.
        A.M. Hussein: Suggested to include modeling aspects.
        V. Shostak: Suggested a more narrow topic:
        - Measurements of lightning current at tall structures
        [in relation to above three topics and initiative of Marina].
        Of course, contributions on other IPTL topics are also possible.
        Participants accepted this topic.
        K. Cummins: It looks that a new CIGRE WG on lightning to tall structure could appear.

         <Also in IPLT we have a postponed preparation of instrumentation list/questionnaire
for tall structure / triggered lightning studies>.

       7. Other business
       Silverio Vicacro have informed participants on two Conferences next year in Brazil (…)
and kindly invited to attend them.

        8. Conclusion
        Farhad Rachidi reminded Partners to send files of their Reports/Comments by e-mail for
placing them at the Project website and for preparation of Minutes. Then he expressed his
gratitude to all participants for fruitful work.

       V. Shostak,


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