45Electricity Today Issue 2, 2004

Since the dawn of civilization, light-ning has inflicted a great deal ofdamage on the structures built by

mankind. About 250 years ago, an effec-tive method of protection became avail-able when Benjamin Franklin inventedthe lightning rod. Its application to powerlines took the form of shield wires. Agreat deal of the research done since thenwas regarding how to best place thelightning rods and shield wires so as toprovide effective protection at a reason-able cost.

In recent years, the marketplace hasbeen flooded with products for alterna-tive protection methods. These includegadgets that claims to eliminate lightning[also called Charge Transfer Systems(CTS)], and rods that claim to emit giantearly streamers that vastly extend theirprotective range (ESE devices). This arti-cle explains the requirements for effec-tive lightning protection, and presents theposition of the scientific communityregarding the claims behind the abovedevices.

THE CONVENTIONAL LIGHTNINGPROTECTION SYSTEM

The science of lightning protectionwas born when Franklin discovered thatlightning was a form of electricity. Theconventional protection method consistsof the following: a) Deploying “air terminals” at suitable

points above the structure to act assacrificial termination points for thelightning strokes.

b) Dissipating the collected lightning 2charges safely into the ground viaground rods that are connected to theair terminals via “down conductors”.

c) Bonding the down conductors to anynearby conducting objects in thebuilding to prevent side flashes.

d) Installing suitable surge protectiondevices on the electric and electron-ic systems of the building.In the beginning, it was thought that

the protected zone was described by acone around the lightning rod. In theearly 1940s, C.F. Wagner applied light-ning impulses to a scale model in an

attempt to define the protected zones ofshield wires and masts/lightning rods.The great R.H. Golde theorized that suchscale models produce invalid results.Field observations on the double circuit345 kV lines of the early 1950s provedGolde’s theory. The ensuing research ledto the development of the electrogeom-teric model (EGM). The Rolling SphereMethod (RSM), which is widely used instandards, is a method of visualizing theapplication of the EGM, and it wasdeveloped by R.H. Lee. The RSMinvolves an approximation as it assumesthe “striking distances” to all objects (airterminals, the ground, and the protectedstructure) to be equal to one another. Theconventional lightning protectionmethod adopted in national and interna-tional standards rests on using Franklinrods that are placed using the RSM.

THE DRIVER BEHIND THEALTERNATIVE AIR TERMINALS

In recent years, some vendors ofalternative air terminals have been wag-ing a war based on claims that have beenrejected by the scientific community atlarge. In the process, they lowered thedebate to the point of denying the exis-tence of the extensive research behindthe EGM/RSM. They then attempted toforce their point of view by using threatsof legal action against the participants inthe debate, both individuals and organi-

zations. This escalated to actual courtaction against NFPA (National FireProtection Association) and others, andsome scientists were humiliated by beingforced to submit to interrogations.

The proponents of CTS and ESEdevices claim to be seeking to introducesuperior lightning protection systemsthat better serve the customer. On theother hand, their real objective appears tobe to make more profits from the sale ofsuch systems. One tactic is to get the cus-tomer to pay more on the grounds thatthe offered air terminals can eliminatelightning. As an example of the pricehike associated with such a claim, thecost of the CTS device called “SplineBall” (US $105) is more than 10 timesthe cost of a Franklin rod ($6-$10depending on length). It should be notedhere that the Spline Ball acts as a one-to-one replacement for the Franklin rod.Hence, the customer in effect pays muchmore for a degree of protection which, atbest, is similar to that of a conventionalsystem.

Another tactic is to offer the alterna-tive system at a cost which is comparableto that of a conventional system, but pro-vide only one or a few air terminals.Also, the number of down wires isreduced to one or two. In contrast, a con-ventional system for the same buildingmay require 20 Franklin rods and many

Continued on page 46

LIGHTNING PROTECTION

WAR OF THE LIGHTNING RODSBy Abdul M. Mousa, Ph.D., P.Eng., Fellow IEEE

Electricity Today Issue 2, 200446

down wires. This is the practice of thevendors of ESE devices, and it rests onthe claim of having a protective rangethat is much larger than that of theFranklin rod. On the other hand, the pro-tective range of an ESE device is practi-cally equal to that of a Franklin rod. Theresult is that the customer pays “the fullprice” for a fraction of the protection.This could have serious consequences tolife and property, especially if the build-ing houses hazardous materials.

As implied by the above, the price ofan ESE device is also much higher thanthat of a Franklin rod. For example, onemanufacturer which offers both systemscharges US $1250 for the ESE device and$10 for a Franklin rod.

LIGHTNING ELIMINATION DEVICESWhile the concept itself is much

older, the commercialization of CTSstarted in the early 1970s. Shortly there-after, studies were commissioned by sev-eral departments of the US governmentto evaluate their effectiveness, and theresults were presented in a report editedby J. Hughes [1]. The conclusion was thatlightning cannot be eliminated and thatthe subject gadgets did not work. Thiswas confirmed by several subsequentstudies. Recently, a comprehensivereview of CTS was conducted byProfessors Uman and Rakov [2]. Again,the conclusion was that the lightningelimination claim was unfounded. Theabove work is of special significance as itwas widely endorsed by the scientificcommunity, including ICLP (Inter-national Conference on LightningProtection), the American GeophysicalUnion and the American MeteorologicalSociety.

Equally important, Russian scientistshired by the CTS people themselvesagreed with the scientific communityregarding the invalidity of many of theclaims that the CTS industry aggressive-ly pushed in the past. For example, themain claim of the CTS folks has been thattheir gadgets produce copious amounts ofcharge that will neutralize the cloud or atleast form a cloud of space charge thatwill neutralize the downward leader. Onthe other hand, the Russian scientistsfound the emitted charge to be not muchlarger than that produced by a single elec-trode. Further, they found the subjectcharge to be incapable of neither dis-charging the cloud nor neutralizing the

downward leader.Another important finding of the

Russian scientists is that lightning strokeswill continue to strike the CTS or the pro-tected object. However, they suggest thatif the stroke arrives beyond a certain dis-tance from the structure, designated “D”in Fig. 1, then the opposing field of thecloud of space charge may be able to can-cel it out, thus inhibiting the formation ofan upward counter leader. Hence thestroke would terminate elsewhere. Let“X” be the effective collection radius ofthe structure in the absence of the CTS.The “failure ratio” of the CTS would thenbe:

F = (D/X)2 ...(1)Based on the assumption that X =

3H, “H” being the height of the structure,and that the downward leader will have aconstant charge density of 0.001 C/m, theRussian scientists suggest that the failureratio will be small.

Contrary to the above, Ref. [3]shows that the failure ratio will be almost100% even if the idealized conditionupon which the Russian model is basedmaterializes. For one thing, distance X isactually much smaller than 3H. Second,proper modeling of the charge distribu-tion in the downward leader may makedistance “D” larger than “X”.

Regardless of the value of the failureratio, the admission of the Russian scien-tists that at least some strokes, especiallythe ones having larger amplitudes, willterminate on the structure renders theCTS not feasible on economic grounds.Further measures will still be necessaryto enable the structure to cope with directlightning strokes. Those same measureswill also enable it to cope with the rest ofthe strokes. Hence, there is no justifica-tion for incurring the additional high cost

of a CTS.ESE LIGHTNING RODS

ESE devices were invented whentheir predecessors — radioactive rods —were banned on the grounds that theirclaimed benefit did not justify the result-ing nuclear pollution. An ESE devicereleases a charge at its tip earlier thandone by a Franklin rod. The charge isclaimed to form a giant upward streamerwhich acts as an extension to the rod. Thedownward leader would then connect tothe tip of the streamer, thus vastly extend-ing the protective range of the rod. Ifsuch giant streamers existed, it would bepossible to photograph them with a streakcamera or a Boys’ camera. The vendorsfailed to produce such photographs, yetcontinued to insist that their theory wasvalid.

Some of the reasons for rejecting theESE theory are as follows: a) a streamercannot form before its natural timebecause the electric field within the gapwill be too low to permit propagation.; b)even if the streamer started developing,its speed would be a small fraction of thatassumed in the ESE theory;. c) accordingto the EGM, a huge increase in the effec-tive length of a lightning rod does notsignificantly decrease the required num-ber of air terminals.

It should be noted that the review byUman and Rakov covered both CTS andESE devices, and rejected both. Therejection of the ESE theory by indepen-dent scientists is also worldwide.Actually, the rejection of ESE theorygoes back to February 1999. At that time,ICLP issued an opposing statement thatwas endorsed by 17 scientists from 15countries [4]. Further, ESE technologywas rejected by independent scientists inFrance, the birthplace of the ESE theory

LIGHTNING PROTECTION

Continued from page 45

Since the dawn of civilization, lightning has inflicted a great deal of damage on the struc-tures built by mankind.

[5].VALIDITY OF THE CONVENTIONALLIGHTNING PROTECTION SYSTEM

The vendors of ESE rods and CTSdevices often attempt to advance theirclaims by alleging that the basis of theconventional lightning protection systemis also questionable. Those allegationshave been rejected by the scientific com-munity. Please see the related policystatement of the AmericanMeteorological Society [6].

In addition to the above, a report byTobias et al [7] proves the effectivenessof the conventional protection method.The Tobias report represents the collec-tive position of 8 respected lightningexperts.

CONCLUDING REMARKSLike the rest of the marketplace,

many false claims exist within the light-ning protection field. Actually, it is easi-er to mislead the buyer in this case ascomplexity of the subject makes the junkscience arguments of the vendors appearplausible to him/her. This fact, coupledwith the power of well-financed com-mercial propaganda campaigns, enabledthe vendors of CTS and ESE devices toget thousands of people to buy theirproducts. In some cases, the damage islimited to overcharging the customer fornon-existent lightning elimination capa-bilities. In other cases, the customer isgiven only a fraction of the required pro-tection, thus exposing life and propertyto risks.

Potential buyers are advised to pro-tect themselves by not entertaining anyclaim unless the vendor submits proofthat it has been accepted by the scientificcommunity at large.

Useful information in this respect

can be obtained, free of charge, from thearchives of the Lightning Protectiongroup. To join, just send a blank e-mailmessage to: LightningProtection-sub-scribe@yahoogroups.com

REFERENCES[1] Hughes, J. (Editor). (1977). Review

of Lightning Protection Technologyfor Tall Structures, Office of Navalresearch, Arlington, Virginia,Report No. AD-A075 449, 275 pp. 6

[2] Uman, M.A. and Rakov, V.A.(2002). “A Critical Review ofNonconventional Approaches toLightning Protection”, Bulletin ofthe American MeteorologicalSociety, Vol. 83, No. 12, pp. 1809-1820.

[3] Mousa, A.M. (July 2003). “Validityof the Lightning EliminationClaim”, Proceedings of the IEEE-PES Annual Meeting, Toronto,Ontario, 6 pp.

[4] Mazzetti, C. and Flisowski, Z. (26February 1999). “The ICLPStatement’s to the NFPA DraftStandard 781”, 2 pp. Included insection 5.4.3 on the web site of:www.lightningsafety.com

[5] Gruet, P. (October 2001). A Studyon Early Streamer EmissionLightning Rods, INERIS (NationalInstitute of Environment, Industryand Hazards), France, 64 pp.English highlights of the Report aregiven in message #1136 in thearchives of www.LightningProtection@yahoogroups.com.

[6] American Meteorological Society.(November 2002). “LightningProtection Systems”, policy state-ment, www.ametsoc.org/AMS/poli-cy/lightningprot_statement.HTML-29k.

[7] Tobias, J. et al. (June 2001). TheBasis of Conventional LightningProtection Technology, Report ofthe Federal Interagency LightningProtection User Group, DTIC(Military version of NTIS),Catalogue No. ADA396784, ReportNo. CECOMTR- 01-5, SourceCode: 412503, 76 pp. Also availableas section 5.1.9 on the website:www.LightningSafety.comAbdul Mousa is a Specialist

Engineer in Transmission andEngineering for BC Hydro. ET

47Electricity Today Issue 2, 2004

Fig. 1. Effect of CTS on downward lightningleader.

Unifin International

Tel: (519) 451-0310 Toll Free: (888) 451-0310 Fax: (519) 451-1732

www.unifin.com unifin@kochind.com

TransformerCooling Products

A member of the Koch Chemical Technology Group

Transformer oil cooling products to the Power Generation,

Transmission & Distribution Industries.