NATIONAL COMMUNICATIONS SYSTEM

Lflm NCS EMP MITIGATION PROGRAM:

AERIAL TI SYSTEMEMP TEST PLAN DTIC

ELECTE

AUGUST 1986 OCT 2 7 IM

D

C) OFFICE OF THE MANAGERNATIONAL COMMUNICATIONS SYSTEM

..._ WASHINGTON, D.C. 20305 !

DCA-100-82-C-0034

Approved for pu6Aic raee4 IDistribution Unlimited"

r ,~( 1, -, -

UnclassifiedSECURITY CLASSIFICATION OF THIS PAGE

REPORT DOCUMENTATION PAGEla. REPORT SECURITY CLASSIFICATION lb. RESTRICTIVE MARKINGS

Unclassified2a. SECURITY CLASSIFICATION AUTHORITY 3. DISTRIBUTION/AVAILABILITY OF REPORT

2b. DECLASSIFICATION / DOWNGRADING SCHEDULE

4. PERFORMING ORGANIZATION REPORT NUMBER(S) 5. MONITORING ORGANIZATION REPORT NUMBER(S)

6a. NAME OF PERFORMING ORGANIZATION 6b. OFFICE SYMBOL 7a. NAME OF MONITORING ORGANIZATION

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6c. ADDRESS (City, State, and ZIP Code) 7b, ADDRESS (City, State, and ZIP Code)

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National Communications System NCS-TS DCA100-82-C-0034

8c. ADDRESS (City, State, and ZIP Code) 10. SOURCE OF FUNDING NUMBERSTechnology & Standards PROGRAM PROJECT TASK WORK UNITWashington, D.C. 20305-2010 ELEMENT NO. NO. NO. ACCESSION NO.

11. TITLE (Include Security Classification)L.CS E P itigation Program: Aerial TI System EMP Test Plan

12. PERSONAL AUTHOR(S)

13#, TY? E OF REPORT 13b. TIME COVERED 14. DATE OF REPORT (Year, Month, Day) 15. PAGE COUNTtinal FROM TO August 1986 30

16. SUPPLEMENTARY NOTATION

7. COSATI CODES 18. SUBJECT TERMS (Continue on reverse if necessary and identify by block number)FIELD GROUP SUB-GROUP -[P

High-Altitude EMP (HEMP)National Security & Emergency Preparedness (NSEP)

ABSTRACT (Continue on reverse if necessary and identify by block number)his program mitigates the damaging effects of nuclear weapons on regional and nationaltelecommunications capabilities. To meet this objective, the ONCS has sponsored efforts tocreate a network level model to assess the effects of KH4-Altitude EP (HEMP). In addition,the OMNCS has sponsored efforts to collect the level HEMP effects to data required to supportthe network-level model. The products of this model will assist the NCS in identifyingpotential vulnerabilities of national telecomnmunications capabilities to HEMP and to supportNational Security & Emergency Preparedness (NSEP) initiatives.

20. DISTRIBUTION /AVAILABILITY OF ABSTRACT 21. ABSTRACT SECURITY CLASSIFICATIONrUNCLASSIFIED/UNLIMITED 0 SAME AS RPT. CDTIC USERS Unclassified

22a. NAME OF RESPONSIBLE INDIVIDUAL 22b. TELEPHONE (Include Area Code) 22c. OFFICE SYMBOLDennis Bodson 202-692-2124 NCS-TS

DD FORM 1473, 84 MAR 83 APR edition may be used until exhausted SECURITY CLASSIFICATION OF THIS PAGEAll other editions are obsolete. Unclassified

Unclasifie

NATIONAL COMMUNICATIONS SYSTEM

NCS EMP MITIGATION PROGRAM:

AERIAL TI SYSTEMEMP TEST PLAN

AUGUST 1986

!

OFFICE OF THE MANAGERNATIONAL COMMUNICATIONS SYSTEM

WASHINGTON, D.C. 20305

DCA-1 00-82-C-0034

S

T AB LE O F CO0N T ENT S

PageNumber

1. INTRODUCTION 1-1

2. SCOPE OF TESTING 2-1

3. TEST OBJECTIVES 3-1

4. TEST FACILITIES AND EQUIPMENT 4-14.1 Test Equipment 4-14.2 Ti Carrier Hardware 4-3

5. TEST PROCEDURES 5-1

5.1 Cable Driving Studies 5-15.2 Illumination Studies 5-4

5.3 est ointSummary5-5Data Collection5-

6. SCHEDULE 6-1

7. REFERENCES 7-1

APPENDIX A: PRETEST ANALYSIS

Accesioi For

NTIS CRA&

UTIC TAB E

I CWJustifcajio11

By

Availabi~ity Codes

is Aval a;'.d orDit Peci

LIST F E XHIBI TS

PageNumber

Exhibit 1. AESOP Simulator 4-2Exhibit 2. T1 Carrier System Configuration 4-4Exhibit 3. Cast - Iron Splice Case 4-5Exhibit 4. Plastic Splice Case (2 Type) 4-6Exhibit 5. PC-12 Cable Enclosure 4-6Exhibit 6. Definition of Cable Transfer Function 5-2Exhibit 7. Structure of KHAG 106 Cable 5-3Exhibit 8. Cable Test Configuration for

HDL Coupling Studies 5-6Exhibit 9. Multiple Cable Configuration 5-9Exhibit 10. Test Point Summary 5-10Exhibit 11. Test Schedule 6-2

Exhibit A-i Simulated HEMP Threat Waveform A-3Exhibit A-2 Cable Test Geometry A-4Exhibit A-3 Cable Response Waveform A-5

IN

I'ag 1.0 INTRODUCTION

The Office of the Manager, National CommunicationsSystem (OMNCS) has undertaken the Electromagnetic Pulse(EMP) Mitigation program to support the survivabilityobjectives addressed by National Security Decision Di-rective 97 (NSDD-97) and Executive Order 12472. Theobjective of this program is to mitigate the damaging ef-fects of nuclear weapons on regional and national tele-communications capabilities. To meet this objective, theOMNCS has sponsored efforts to create a network-levelmodel to assess the effects of High-Altitude EMP (HEMP).In addition, the OMNCS has sponsored various efforts tocollect the level HEMP effects data required to supportthe network-level model. The products of this model willassist the NCS in identifying potential vulnerabilities ofnational telecommunications capabilities to HEMP and tosupport National Security and Emergency Preparedness(NSEP) initiatives.

In support of the OMNCS efforts to obtain appropriateequipment-level HEMP effects data required for thenetwork-level model, the OMNCS is assessing the surviva-bility of the aerial T1 carrier system. The survivabilityof buried T1 carrier system against the effects of HEMPwas the subject of extensive analysis and testing effortsunder the Tl/FT3C Nuclear Weapons Effects project, whichwas funded by the NCS (Reference 1). As a result of theseefforts, a wealth of information exists, some of which isapplicable to the aerial Tl equipment. The approach toIthe aerial TI assessment is to use as much of the existingdata as possible and to augment that data, where appropri-ate, through analysis and simulation testing in order toidentify potential vulnerabilities to HEMP.

This document is a plan for the simulation testingportion of the aerial T1 carrier system assessment. Thistest plan identifies the following: test objectives, datathat are to be collected, the logistic support required toaccomplish the test, and pre-test analysis.

5 1-1

2.0 SCOPE OF TESTING

Many equipment configurations exist for Ti carriertransmission systems. For the purpose of this program,the selected test configurations are representative ofthose found in recent aerial installations.

To avoid the added time and expense of conducting anoperational test program, this test will be conducted as acoupling study for representative Ti aerial cable configu-rations. The coupling studies will be used in conjunctionwith the results of related test programs (Reference 1, 2,3) to assess the survivability of lightning protected andunprotected systems against early time HEMP.

VIn order to assess the system survivability, the mea-sured cable transients and cable properties will be usedto establish the threat signal levels that would be seenby aerial Ti system repeaters, channel banks, andTransient Protection Devices (TPDs). Switches will not beused in this test since other test programs are addressingtheir survivability. Repeaters and TPDs were tested dur-ing the Buried TI Carrier Tests. Tests are being conduct-ed on the D4 channel bank and the 5ESS switch, while othertests are being planned for the DMS-100/200 switch

2

U 3.0 TEST OBJECTIVESThe purpose of the Aerial T1 Cable tests is to develop

an empirical data base describing the transients inducedon typical T1 cables in the HEMP threat environment.*This data base will support the survivability assessmentof the aerial T1 Transmission System to HEMP.

The general objective of this series of tests will beto measure the coupling of simulated HEMP to long aerialcables. The specific objectives, for a representativecable configuration, are as follows:

To measure bulk, binder, and signal wire inducedtransients for a representative aerial Ti cable.

• To measure the propagation characteristics (im-pedance, propagation constant) of the cable(s)above a finite ground plane.

• To measure the coupling and propagation charac-teristics of cables with typical splice caseconfigurations installed.

o By completing these objectives, a data base consistingof transfer functions can be obtained to evaluate the in-duced stresses at line repeaters, TPDs, and D4 channelbanks. These results can be used to help assess systemsurvivability when they are integrated with the results ofD4 channel bank testing, switch testing, and the dataobtained on repeaters and TPDs in the Buried T1 Cabletests.

*That is, the 50 kV/meter double exponential threat (DBEX)discussed in Reference 4.

* 3-1

161 *Y?

3 4.0 TEST FACILITIES AND EQUIPMENTIn order to carry out the test program on a repre-

sentative aerial T1 carrier transmission system, the fa-cilities at Harry Diamond Laboratories (HDL) WoodbridgeResearch Facility will be used for cable driving and fieldillumination studies. The test equipment and T1 carrierhardware is described in this section.

4.1 TEST EQUIPMENT

A wide range of facilities at HDL will be used. Thecable testing laboratory at HDL will measure common-mode

'J propagation properties of Ti carrier cables. HDL has tworadiating field pulse generators that can be used exten-sively to study the electromagnetic coupling to the cables.

The radiating pulser to be used is called the Army EMPSimulator Operation (AESOP). The AESOP is a300-meter-long, 20-meter-high (approximately 984-feet by65-feet), radiating dipole antenna. The AESOP generatordrives a 7-million-volt pulse through a biconal antennaand down a horizontal transmission line composed of acylindrical array of wires. The transmission line isterminated to ground at both ends (see Exhibit 1). Thebiconal antenna forms the early-time shape of the pulse,while the transmission line forms the late-time portion ofthis pulse. The AESOP produces, at most, a 50-kV/meterhorizontal incident field at 50 meters and a 25-kV/meterincident field at 100 meters (300 feet). Couplingexperiments will be performed at the latter field level.This field is largely horizontally polarized. The near-induction-zone fields under the simulator reach magnitudeson the order of 100 kV/meter.

The tests to be conducted at HDL will use the cabledrive laboratory to do Time Domain Reflectometry (TDR) andobtain signal wire-to-sheath transfer functions. The Sys-tem for Monitoring and Recording Transients IntermentationVan (smart IVAN) will also be used to record data and pro-vide quick look plots as well as on-site data processingfor the field studies.

3 4-1

Exhibit 1. AESOP Simulator

ITRANSMISSION LINE CONTROL HOUSE

TOCA ANTOUND

WODPLXTp

4-2

4.2 Ti CARRIER HARDWARE

A typical Ti carrier system might be arranged as shownin Exhibit 2. The central office equiment is shown in theboxes and is interconnected by the outside plant equip-

Vment, consisting of T1 carrier lines. The remote customerend is served by the channel bank, protection switch, andoffice repeater combination as shown to the left. Theoptional protection switch changes to a spare T1 carrierline in the event of a signal failure at the receivingend. At an intermediate central office (e.g., in thelower box) the entire digroup is demultiplexed so thatsome voice-frequency channels may be directed to a cus-tomer while the remaining voice-frequency channels aremultiplexed onto the outgoing Ti carrier. The third typeof office configuration shown in Exhibit 2 is used onlyfor supplying power to the T1 carrier line; there is novoice-frequency application.

The outside plant equipments for this system are re-peaters and splice cases. The 818/819-type repeater caseis designed to house 25 T1 carrier repeaters, a fault lo-cate filter, a pressure contactor, and other ancillaryequipment see Figure 3. The case is molded from a fiberglass-reinforced plastic (sheet molding compound) and de-signed to be either pole-mounted or installed in amanhole. The case has been in manufacture since 1978 andis the primary case now being deployed for the T1 carriersystem.

Three types of splice cases are employed for Ticarrier routes. Cast-iron splice cases, such as the 30Dtype; plastic splice cases, such as the 2D2 type; andpedestal cable closures, such as the PC-12. .

The cast-iron splice case is designed to be usedaerially, buried, or in manholes. Cable-sheath continuityat the splice case is Pchieved through the cast-ironhalves of the splice case itself and with a copper braid(see Exhibit 3).

The plastic splice case is also designed to be usedaerially, buried, or in manholes. Cable-sheath contin-uity at the splice is achieved by bridging across thesplice with a copper braid (see Exhibit 4). This arrange-ment provides a good current path across the splice.

The pedestal-type cable closure is designed for use Iwith buried or aerial cable where the splice closure canbe mounted at ground level (see Exhibit 5). Continuity ofthe cable sheath at the splice is achieved with copper

W bonding cables that provide a good DC path across thesplice.

3! 4-3

Exhibit 2. Ti Carrier System Configuration 4

END CO TI CARRIER EXPRESS COCABLE EPESC

I LR

VF L, F CB SW OR OR SW SW OR

SWRCO

CS CHANNEL BANK

SW PROTECTION SWITCH CB

OR OFFICE REPEATERCO CENTRAL OFFICELR LINE REPEATERVF VOICE FREQUENCY VF '

4-4

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.. ".,..,".

Exhibit 3. Cast-Iron Splice Case

I

STEEL

PLASTIC SHEATH

8 SEALING TAP

ELECTRICAL CONNECTIONACROSS SPLICE IS PROVIOED

710 CONNECTOR BY CAST-IRON CASEANO BONO WIRE

0.

4-5

I

Exhibit 4. Plastic Splice Case (2 type)

RECTRICAL CONNECTION ACROSSSPLICE IS PROVIDED By COPPER BRAID

PLASTIC SPLICE CASE710 CONNECTOR

Exhibit 5. pC-l2 Cable Enclosure

710 CONNECTOR

4~j STEEL BAR

* 4-6

5.0 PROCEDURES

The objectives of the TI Aerial Cable Test will be metby several complementary activities. These activitiesinclude laboratory cable driving studies, field illumi-nation studies, and analytical studies. This sectiondiscusses the activities and test configuration in detail,and as present a summary test matrix for meeting theobjectives discussed in section 3.0.

5.1 CABLE DRIVING STUDIES

A series of laboratory surge tests will determine thetransmission characteristics of a representative sample ofmultipaired cables and splice cases. These transmission-line tests include measuring the transfer impedance, Zt,

transfer admittance, YT, the common-mode characteristicimpedance, Zo , and the propagation constant, 7, as func-tions of frequency. Exhibit 6 illustrates the definitionof ZT. A knowledge of ZT, YT, ZO, and 7 will per-mit a calculation of the transient response of this cable.

As a cross check, the transmission line measurementsalso will include data taken in the time domain usingtime-domain-reflectometry (TDR).

Exhibit 7 illustrates the structure of KHAG 106, aspecifically designed aerial Ti cable. The core of thecable is shielded primarily by the aluminum sheath. T1carrier cables generally have 100 or more twisted wirepairs arranged in groups of 25 pairs. Each group iscalled a binder group. These binder groups are surroundedby various metal shields. Each binder group twists at auniform rate with respect to the others; however, thebinder groups do not braid. The pairs within a bindergroup twist with respect to each other. The KHAG 106cable has four binder groups.

5.1.1 Cable Sheath

The transfer function, ZT, of a representative3 meter length of Ti transmission cable, the KHAG 106,will be measured. The measurements will help determine

NI the shielding effectiveness of the aluminum outer sheath.

'5-1

I

En, NORMAL ELECTRIC FIELD

IIE I dV

ZT=T -:1

DIFFERENTIAL di 0 2

OF CABLE Io10z ~ !TSd

Kdy--

TOTAL CURRENT ILOAO AT THlE END OF THE CABLE IS GREEN'S FUNCTION

2Z0 f

5-2

Exhibit 7. Structure of KHAG 106 Cable

POLYETHYLENE

ALMIUCORE WRAP

SCEE

TWISTED PAIR

5-3

5.1.2 ZT Measurements

ZT from the cable sheath to conductors within thecable core will be measured as a function of frequencyover the relevant EMP range. These measurements, to beconducted at HDL, will determine the following quantities:

ZT from the sheath to a binder group within thecable

. ZT from the sheath to a single conductor withina binder group

* Differential voltages between binder groups andbetween single conductors within binder groups.

5.1.3 Time-Domain Reflectometry (TDR) Experiments

TDR experiments for the KHAG 106 sample, will measure,

The characteristic common-mode impedance

. The common-mode propagation constant.

5.2 ILLUMINATION STUDIES

Field experiments with AESOP will determine the coup-ling of the horizontal simulated EMP components to thecables and the line splice case structures. Coupling tothe core conductors in these long, multipaired cables oflarge cross section is not well understood. It is diffi-cult to make predictions with high confidence about in-duced transients to the core conductors and, thus, to theterminating line repeaters. For those reasons, field ex-periments will be taken to determine coupling on the

aerial cable configuration.

Since a high-altitude EMP extends over an area ofIM thousands of square miles, it would uniformly excite the

1 mile (1.6 kilometers) of cable between T1 repeatersites. No existing simulation facility can produce uni-form fields over such dimensions. However, as shown inAppendix A, shorter lengths of aerial cable can accur-, - ately produce the early-time response of the cable sheath

open-circuit voltage to a simulated EMP. Cable lengths ofseveral hundred feet are sufficient (shown inAppendix A). Extrapolations for optimal couplingorientations will be made to estimate the optimal coupledtransients.

2JI

5-4

To study the coupling of a horizontally polarized EMP,two mirror image lengths of cable will be suspended alonga circular arc of radius 100 meters about the center ofthe AESOP (see Exhibit 8). The cable section A has splicecase sites and a steel support messenger strand that isbonded to the guy wires and splice cases. This geometrycoincides approximately with contours of equal arrivaltime and field.strength of the pulse; this simulatesplane-wave incidence along several hundred feet of cable.A calculated representation of the sheath-current waveformis presented in Appendix A.

There is another aspect for which the experimentalarrangement differs from the normal outside plant configu-ration. In commercial installations, cable is suspendedat about 6 to 7 meters, but for the field tests the cableswill be suspended at 5 meters.

The primary function of cable A and the splice casesite on the simulator centerline is to determine the char-acteristics of a typical aerial configuration with theappropriate support, grounding, and bonding practicesinstalled.

Measurements of bulk current and individual conductorcurrent taken on cable A will be compared with correspond-ing measurements made on cable B. The effects of the sup-port, bonding, and grounding can be compared using cableB, where the cable configuration does not have the bondingand grounding practices installed.

5.2.1 Field Coupling Studies

Exhibit 8 also shows the test point locations at theAESOP site. Two sections of 168 meters long and 5 metershigh will be arranged in a circular arc at a distance of100 meters from the center of AESOP. These cables werereferred to as cable A and cable B, above.

Test points 1, 5, 6, and 10 are the end points ofcable sections A and B and will be grounded while bulkcurrent measurements are made at test points 2, 3, 4, 7,8, and 9. The type of termination that yields the bestground will be determined experimentally.

I 5-5

MO R 14~

Exhibit 8. Cable Test Configuration for HDLCoupling Studies

S L C CA E TP3 CABLE A

TP2) TP4

TP1 ITP5*. a:300

____450__ - 450' -

** **:300'

TP10 TP6I TP7 >,,

T9TP8 125' CABLE B

5-6

-1 r -

I

Individual wire measurements will be obtained by in-serting a repeater housing (no repeater) at test points 2and 9. Measurements will be taken of the open-circuitvoltage (Voc) and short-circuit (Isc) current as wellas the differential voltage (VDIF) on the input and out-put leads in the antechamber to a repeater case.

The cable (section A) core response will be measuredat TPl, with TP5 grounded, as follows:

Isq and VOC to earth ground for the cableshield

ISC and VOC for each distinct binder group tothe cable shield

I$C and VOC for a single conductor in eachbinder group to the cable shield

0 The differential voltage between distinct bindergroups.

Time Domain Reflectometry (TDR) experiments will beperformed on the cable sections. The procedure will be toinject a signal at TP5 to measure the common-mode trans-

VL mission parameters (i.e., characteristic impedance andpropagation constant). The results of these measure-ments can be compared to the 3 meter cable in the labora-tory studies. For comparison, similar measurements (TDR,bulk, and individual wire) will also be made on cablesection B.

5.2.2 Splice Case Studies

For cable section B at TP8, typical aerial Tl splice'cases can be inserted in the latter stages of the couplingstudy after measurements are performed with no splice inplace. The measurements with the splice case(s) in placecan help determine the extent of the current induced insignal leads by the sheath current at the splice. Becausethe cable terminates abruptly at the splice case, radia-tion from the sheath is expected because of the large im-pedence change. This radiation will partially manifestitself as transients on the signal wires.

The types of measurements at the splice case(s) willinclude:

. Bulk current on each side of the cable

'SC and VOC inside the splice case on thecore, binder group, and signal wire.

5 5-7

5.2.3 Current Sharing Studies

In most cases, aerial Ti cables will have additionalI cables suspended in parallel over a portion of a givenroute. Exhibit 9 shows a typical multicable configurationthat can be present in a system. Additional illuminationstudies for this configuration will help to characterizethe effects of mutual current sharing on the transmissionsystems.

In this experiment, the bulk current will be measuredon up to three cables. These measurements will becompared with the measurements on the bulk current forsingle cables and compared with the results of the bulkcurrent for the single cable. Though the sheath currentmay be reduced through mutual induction interactions, thetotal current may actually increase over that of one cableat a termination.

5.3 TEST POINT SUMMARY

Exhibit 10 shows a summary of measurements to be madeat the test points. Each of the measurments will con-tribute to satisfying one or more of the objectives out-lined in Section 3.

5.4 DATA COLLECTION

All data will be taken with fiber-optic instrumenta-tion and the IVAN. For measurements at the ends ofcables, HDL will provide a well-shielded breakout box sothat the individual cable and internal bulk currents can3be measured.

Individual data records (paper plots and floppy disks)are provided for each shot. These data will be correctedfor all instrumentation calibration. A B-dot monitor willbe used to record the'relative field strength for eachsimulator pulse. Measurements of the magnetic and elec-tric fields close to test points 1 through 10 will also bemade prior to field testing of the system.

I3 5-8

Exhibit 9. Multiple Cable Configuration 6

I1J5-

L r

Exhibit 10. Test Point Summary

TEST POINT SUMMARY

CABLE TEST POINT ACTIVITY

A TP1 TDR mesurements (input)

A TP2 Signal wire measurements

A TP3 Splice case insert - bulk & signal current measurements

A TP4 Bulk current measurements

A TP5 TDR measurements - bulk current measurements

i B TP6 TDR measurements (input)

B TP7 Signal wire measurements

B TP8 Splice case insert - bulk & signal current measurements

B TP9 Bulk current measurements

B TP10 TDR measurements - bulk current measurements

5-10

I 6.•0 SCHEDULE

~Exhibit 12 is a test schedule that will require six

weeks of testing at HDL. The start of this test period is~October 1.

I-. .

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1 6-1.,?

Exhibit 11. Test Schedule

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B7.0 REFERENCES

1. Nuclear Weapons Effects. Ti EMP/MND Hardness Assess-ment and Design, Final Report, Volume 1-17. November29, 1985, AT&T Bell Laboratories.

2. EMP Assessment of D4 Channel Bank, in progress.

3. EMP Assessment of SESS Switch, Final Report, inpreparation.

4. EMP Engineering and Design Principles. Bell TelephoneLaboratories, 1975.

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* - -. -. ,.

APPENDIX A

PRETEST ANALYSIS

3 A-1

U APPENDIX A

PRETEST ANALYSIS

A widely used characterization for the early-time HEMPthreat waveform is the double exponential (DBEX)expression:

E(t)=EO (e-Pt - e-at)

where

E0 = peak field amplitude =52.5 kV/m

'= 4.76x10 8 sec -1

= 4.00x10 6 sec-1

Exhibit A-1 displays this HEMP waveform which is thewaveform at 50 meters from the AESOP HEMP simulator. Alsoshown is the waveform at 100 meters from the pulser wherethe test cable will be located.

To estimate the coupled transient on the cable sheathin this test, the Electromagnetic Pulse Effects on Cables(EPEC) program was used. This program uses a DBEX pulseto calculate the voltage or current transients on lossyaerial or underground cables. The geometry of the testconfiguration is shown in Exhibit A-2. From this geome-try, the coupling of the simulated threat can be calcu-lated for horizontal polarization (the primary polariza-tion of the AESOP simulator).

The estimated response of the cable to the simulatedthreat field at 100 meters is shown in Exhibit A-3. theEPEC program assumes a simi-infinite length of cable. Forpractical purposes, this assumption is valid for finitelength cables if the length of the cable used in the testis sufficient enough to couple at least twice the pulsewidth of the transient. The length of cable required bythis criteria is 500 feet.

* A-2

'W it )IIIK

Exhibit A-i. Simulated HEMP Threat Waveform

00

C-

/ Iin

Ln M N

H313 S11AG

A-3 ~ .

Exhibit A-2. Cable Test Geometry

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A-44

Exhibit A-3. Cable Response Waveform

0

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I A-5