research on on-line dga using ftir

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Research on on-line DGA using FTIRLiu Xianyong, Zhou Fangjie, and Huang Fenglei

these two kinds of detectors are still in its infancy and haveAbstract-Electrochemical sensors and gas chmmatography ' encountered many problems that optical detecting methods

are widely used in on-line monitors for dissolved gas-in-oil ofpower transformers,but some fatal defects exist. In view of themany advantages of FTIR, the basics of applying it on suchmonitors are studied and results are prcsented. Investigationshows that ail the characteristic Deal\s needed to be analwed

could avoid naturally. The most outstanding advantages of anoptical detector are their non.destruct,ve and nocharacteristics; and with FTIR spectroscopy, it is reported'"'that the amount of all the diagnostic gases as well as water

can be covered if the measurable wavenumber rcgion of thespectrometer is 720cm.'- 3400cm.', and the optimum optical

content except hydrogen could be measured slmultanwusly ma satisfactory precision

that such B monitor'can. be consiructed using FTIR that can FTIR spectroscopy are investigated recently'"', no rePo* onDreciselv detect all the diamostic eases excent hvdrocen and are FTIR suectra used in DGA has been made in China.0 . ~ ~.free of consuming gases aswell as in situ calibration.

Index Term-DGA, dissolved gas-in-oil, FTIR, gas cell,infrared spectra, on-line monitoring, optical length, powertransformer.

1 INTRODUCTIONHE reliability of power transformers is more and more

electricityi1'. The concept of conditionhased-repairing hasbeen proposed for years"], yet its pi-actice completely depend son the development' of on-line monitoring techno1ogy''l.Various on-line dissolved gas-in-oil monitors have hcendeveloped in the past twenty years and have long beenrecognized as the m ost effective for incipient fault diagnosis"].Widely used on-line monitors are mainly hydrogen mouitorsl5Ior total amount gas monitors. These kinds of monitors cannot take the place of conventional laboratorial gaschromatographic instruments as they can not monitor all thediagnostic gases and its measurement range and resolutiont6]is not comparable to the latter too. What a cundition-based-repairing needs is an on-line multi-gas m~uitor' '~, ith all thediagnostic gases measured in a precision that a labratory gaschromatographic instrument could provideis1.

The key part of a gas monitor is its gas detector. On-linedetectors include chemical sensor^^^', theiiiial conductivitydetectors (TCD), and optical detectors. Although grcatendeavors have k e n made to solve the problems of electro-chemical sensorsiIoI and T CDs, m ulti-gas monitors using

T.mportant with our life and work more and more built on

This work wa s supported in part by Ihc innovation funds far middle andsmall s i l d e n t q r i n a by hlinislry of Finsncc, and Ministry of Scicnce an dTechnology ofthe Pcoplc'r Repubiia o fCh in a . Conlracl No . 01C26213310365.

xinnyang Li u i s wilh Ningha Online Monilorlng S y s l m Co. Lid. (c-maikl i ~ ~ i . ~ y ~ . s ~ h a m a i l . c a m )

Justifiably, this paper set out to explore its basics and someinitial results are presented.

11.. BASICSMajpr diagnostic gases have been identified as hydrogen(1-12), methane (CB), ethane (C&), acetylene (C2H2),

ethylene ( C 2 B ) , carban monoxide (CO) and carbon dioxide(CO,), and their wncentrations in oil may range from 1 ppmto 2000 ppm or even higher. The concentration rangcrequired to measure is shown in Table I and the followingwork is to realize an on-line quantitative analysis of thesegases using FTIR that can satisfy al l the requirements.

Table IMeasurement ange lo br acquired or Dissolved gas-in-oil

A. ,SpecIra RegionBy using Nicolet 670 FTIR spectrometer, the FTIR spectraof C B , C2H2 , CO, CO2, C&, and CzH6 in d ifferent

concentration are collected. The device sketched in Fig. 1 isdesigned, made, and used to dilute high pure gas to getdifferent samples. Where high-pressure nitrogen is used topurge all the parts of the dilution system, and a I ml syringeis used to inject pure sample into the 25 ml dilution cell, andthe sample is diluted fii-stly, then an appropriate syringe isuscd to convey certain amount of the diluted gas into the gas

0-7803-7459-21021$17.00 0 2002 IEEE - 1875 -


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rcell of the FTIK spectrometer. The readout of the pressuregauge, the volume of he dilution cell, the amount of sampleinjected into the dilution cell and mixed into the gas cell, andthe volume of the gas cell can estimate the gas concentrationin the order'of magnitude, it is about 200ppm to 20ppm.

Fig. 1 Simplegas dilution systemThe main parameters of the spectrometer are: 70mm-long

gas cell using KBr windows (its volume is about 50-70 ml),DTGS detector. The average spectra of 32 times scanning ofeach diagnostic gas and water are shown in Fig. 2, theirresolution are al l l.Ocm.'. The concentration used to collectspectra a s in Fig. 2 has been adjusted such that the weakestabsorption regions are sufficient to measure, yet the strongestabsorption peaks a re not severely saturated.

CO

CO2

CH4

C2H6

3000 2000 1000Wavenumbers (cm-1)

Fig 2 FTIR SpectraofD i a g n a l l o gases an d Wafer

The corresponding signature absorption regions aresummarized and listed in Table 11. Data in Table I1 showsthat the signature regions covered is 610-4 000c m~'. In vicwof regions of H?Ond CO2at low frequency and the region ofCO i at high frequency may not be necessaiy and the region of

C2Hi a t high frequency is very weak, the wavenumber rangecan be safely fixed in 720 m.'- 3400cm.'An on-line monitor I s supposed to be used under

atmospheric environment, i.e., optical materials to be used aswindows and splitters should'be insoluble in water, otherwiseit will not be long term stable. In this point, spectra region isof primary importance in choosing optical materials. Inaddition, spectra region also decides the digital samplingfrequency of the upcoming FTIR spectrometer.B. Gas Cel/

I ) GasCe/lMethod:When making quantitative analyses of gases with FTIR ina laboratory, a gas cell method"2' is usually used . 1R radiationis passed through a gas cell. The background spectrum isrecorded first when the cell is fulfilled with nitrogen (N2).Then the gas sample is sent into the cell. Some of the infraredradiation is absorbed by thc sample and some is passedthrough. In data processing course, the background spectrumis subtracted from the sample spectrum and the absorptionspectrum of the sample is thus given.2) Restriction9 to Gas Cell:In constructing a gas cell, its length and volume are theprimary parameters to m ake certain. Longer optical path has

a smaller minimum detection limit, yet it lowers themaximum detection limit: when the light energy at a specificwavelength is completely absorbed passing through the gascell, any highcr concentration will have the same absorption,hence i t is impossible to measure any higher concentration.Furthermore, in on-line monitoring of power transformers,it's veiy difficult to separate a large amount of gases to bedetected by usual FTIR spectrometers. A current 2.4-meterlong optical path gas cell has a volume of 100 ml a t least, butwith the current vacuum separation method, only 5 m ldiagnostic gases can be separated a time, and a 10ml gas cellusing peimeablc membrane nccds 45 hours to reacheq~iiibrium'"~. bviously, what we need is a gas cell with alength as short as possible so that its volume is as small aspossible and its construction is as simple as possible todecrease' the costs and to applicably measure the smallamount of gases.3) Optinrzmi Optical Lengtlr:

a) Theow:According to Absorbance Law, absorbency A isproportional to the concentration c of the sample, the optical

path length 1 of the gas cell, and the absorptivity a of thesample:A =ncl ( 1 )

According lo ( I ) , to the same kind of gas (a is the same), ifc l = const., then the absorbency is the sam e, i.e., to the samespectrometer, if its lowest measurable concentration to aspecific ga s is Cl when the optical length is L , , to measure a

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concentration of C, of the very gas, the shortest optical lengthshall be.

charvoteristic WBVP-numbedcm.' (HdHn)ar

CiHa 729.97(7511)CH, 3014.00(45/0.5)C>H, 949.64(5511)C,H, 2959(1813)CO2 2360(>118/1)'CO 2168.06(9613) . . '

Generally speaking, it is very difficult to get the lowestmeasurable concentration C , of a specific spectrometer, but itis possible to deduce it from the spectra of a measuredconcentration C. Suppose that under the same set ofinstrument parameters, the signal-to-noise ratio (S") ear tothe lowest detection limit C,,,, (when all the parameters areadjusted to the most sensitive status) is a constant, then wehave:

CilO.6 Lsimm1.69( 1) 54 34(CO 10') forCa4.25( 1 ) 113 486.67( 3) 97 89'6.41(20) 1285.6% 5) 846 3 7 0 0 ) 13

CS INC,, =- (3)

If a known concentration C Is measured with an opticallength L , and the height of the specific absorption peak is Hswith an average noise height HN . then .the shortest opticallength L, to detect the lowest measurable concentration CO sgiven by:

speed while measuring. Parameters of the instruments areadjusted as the same scanning speed, 0.3154cm/s, and thesame resolution, 4.0cm-l. Fig. 4 and Fig. 5 are clipped fromthe typical spectra collected. Since data in Fig. . 4 .shows a5mm-high absorption peak with a 0.8mm-high noise nearbyf o r 4 . 2 5 ~ 1 0 . ~l-L when using a 7Omm-long gas cell, i48mm -long gas cell is needed to measure 1x10-6C a . SinceFig. 5 shows Smm- and l0mm-high absorption peaks withthe nearby noise about 2mm-high for 6 . 6 7 ~ 1 0 "C ~ H I nd1 . 6 9 ~ 1 0 ~ ~,H2 respectively when using a 100mm-long ga scell, the shortest optical length of the gas cell should be89mm a nd 34 mm t o m ea su re 3 ~ 1 0 . ~2H , and 1~10 .~,H,respectively. These results ar e appended lo Table 111.

b) Experiments:Mixed diagnostic gases with appropriate concentrationswere measured on Perkin Elmer Spectrum GX. A glassenclosed gas cell with a 2.4m optical length was used. It wasan 11.5cm long cylinder with a volume of 100m1, and itsoptical length was given after 24 times reflection. Ultra highpure nitrogen was used a s balancx gas to guarantce theprecision. When the scanning speed was O.OScm/s, and theresolution was 4.0cm-', an average of 16t ime s scanning gavea typical spectra shown in Fig. 3, there ppm representsits data of main characteristic absorption peaks issummarized and calculated in Table 111 Where CO ha salready 'taken the m inimum detection limit for eachdiagnostic gas.

I7 2 Y . hCZH2.1.6Yppm

Fig. 4 DeteEtion limit onNicolet 560with B 70 mm-longgar cell

Fig. 5 D e l e d o n limit onWQF-410wth B LO U mm-irmg gm oell

Fig. 3. S p m m of m i x 4 diagnostio gas s Results from spectra of diagnostic gases on Nicolet 560,WQF-410, and Perkin Elmer Spectrum GX in Table 111 showclearly that the shortest optical length of a gas cell to satisfyNicokt 56 0 with a 70mm gas "I1 and On WQF-41@FTIR the,minimum requirements on detecting dissolved gas-in-oilspectrometer with a IOOmm gas cell. TObe precise, the mixed of power shall be less than 128mm, Analyses ofgas is continuously flowing through the gas cell with a steady

Then the Same mixed gases ar e

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the spectra collected show that the precise quantitativemeasurements mainly depend on resolution, sensitivity andbase line comeclion. For FTIR spectrometers, it is well knownthat the length of the scanning path decides resolution, the,scanning speed decides sensitivity, and a high quality baseline adds precisions to the measurements. Usually slowerscanning speed is more sensitive, but it is up to the frequency-response properties of the detector, the amplificationcharacteristic of the pre-amplifier and its successor. For theminimum detection limit is mainly decided by sensitivity, andspectra collected in our experiments show that the sensitivityof the 3 different laboratory FTIR spectrometers are almostthe same in the order of magnitude, the upcoming on-linemonitors using current laboratory FTIR technology can safelytake the average manufacturing level, i.e., the optimumoptical length can be suggested as 150mm.

In this length, the lowest measurable concentrationscorresponding to CR, C&, CZH2, z R , CO , and CO 2 canbees t imatedas0.6x10-6, 17x104, 0 . 3 ~ 1 0 - ~ ,. 9~10~~,.8~10-

an d 0.9~10.~espectively. This suggestion has consideredthe fact that data from spectra in Fig. 3 are not measured inthe most sensitive set of parameters of the spectrometers, datafrom spectra in Fig. 4 and Fig. 5are very close to their mostsensitive status, and the sensitivity of on-line monitors maydecrease with the severe on-line conditions such aselectromagnetic interference and etc.

4) Design ofthe gas cel l :

k0i-0m+0730

O i l o u t l e t It1Fig.6 Sketch o fa gar oell

Were a 150mm-long optical length the optimum; itscorresponding gas cell could be made with no reflectionmirror and its volume could be smaller than 100m1, even assmall as 40ml. Then the most commonly used separation gascellusin g permeable memb rane on current on-line monitorsmight supply enough measurable gas to rcalize a continuousmonitoring. As the high temperature oil in the transformermight be harmful to infi-ared optical parts and DIGSdetectors, so to maintain the convention that the detector isequipped within the separation gas cell, an economic noveldesign is proposed in Fig. 6 . The sketch shows thattransformer oil is introduced into the shell of a cylinder and,pumped back to the transformer powered by oil circulatingsystem.

Permeable materials coated on the inner wall made bypowder metallurgy can continuously separate dissolved gasesfrom the oil. Temperature of the gas cell can be adjusted by along tubule exposed in the air by appropriate oil flowingspeed. As a sophisticated expensive multi-pass gas cell isavoided, such a sttucture should be economic and practical,thus crucial in promoting the use of FTIR for on-linemonitoring of dissolved gas-in-oil of power transformers.C. Background Deduction

The background deduction technique in a gas cel l methodresults in a spectrum that has all of the instrumentalcharacteristics removed. Theoretically, A single backgroundmeasurement can be used for many sample measurementsbecause this spectrum is characteristic of the instrument itself.This has k e n an ideal method to labra tory FTIR, but willnot be true to on-line FTIR, because the parameters of theequipment may vary with environment and time, and frequenton-line background collection is not easy to realize. It isfeasible to find a reference through a vacuum gas cell, but therelative vacuum system is sophisticated, adds difficulties andexpenses, and to fulfill the gas cell with complete freshdiagnostic gases again may be no t so easy or at least timeconsuming.

G ao J i a n k ~ [ ~ roposed a m$hod on realizing quantitativegas analysis with no background FTIR spectroscopy. In themethod, transmittance spectra were successfully extracted byusing wavelet transmission (W T) method[. T he method isimproved to acquire real absorbance spectra here. D igital W Tis realized by Java . DK .4 .

3000 2000 1000Fig.7 Transmittance Spectra of Oil Vapor,Background Spcctm and theirBackground y W I

Fig . 7 shows a transmittance spectra and its background ofgases vacuumed into the gas cell from top space of No. 45transformer oil. It is collected on Nicolet Nexus 670 FTIKspectrometer, with a resolution of 1.Ocm. and a 2 . h - l o n goptical length gas cell. Where T means Transmit tance,OilVapor means the gas source, and WT means thercsults hy Wavelet Transmission. Note that even thebackground spectra possesses a WT background.

The spectra data a re in .csv format (a text format using

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commas as separators). They are transformed by OMNICsoftware supplied by Thermo Nicolet. The WT program readin data in .csv format while working, and save the slow wave(background) data in the same format after WT completed.The data is characterized in 74 70 data points, its wavenumbercoordinate begins at 399.1992cm.' and ends at 4000.1882cm?,with a 0.482125 cm- ' data spacing.

I I I IA B.c*orDyld WTI

w.*.num*rr / C r n l )Fig. S Absohsnce Spectra ofoil Vapor,

By W T and By Real Raokground divided,And That of Bwkmound bv WTThe absorbance spectra are results of transmittance spectra

divided by its corresponding background and then calculatedwith minus logarithm in base 10. The absorbance spectra ofoil vapor (A.OilVapor, with its real backgound divided), thatby WT (A.Oi lVap oi.W T, with WT background divided), andthat of its background by WT (A.HackGround.WT), areshown in Fig. 8 .

I A . 8 a c k G m u n d . W A

other except that the size of the former is bigger than thelatter as the environment absorbance of the spectrom eter

Background deduction by W T is both efficient andeffective in eliminatjng the affection of parameter variation ofthe spectrometers, and is really beneficial in reducingmanufacturing costs and is free of consuming high pureinertia gas, yet it is two edged, the carbon dioxide, watercontent and so on in the air of the spectrometer must bedismissed in other ways.

ei

Ftg. 10 ComparisonofAbnorbanceSpectraBy WT andBy Rcal BackgroundDivided(The Shape)

D. Independence oJA bsorbance Spectra

A V a p o r G a i n i . O M i i,2085.4 120a " '30 1I

Fig. 9 Comparison of Ahorbance SpectraBy WT and By Rcal Background divided (I n Detail)

Fig. 9 compared those absorbance spectra obtained indifferent ways in detail. It shows that the relationshipsbetween their peak hcights can be expressed as: 60+2=62 at2180cm-', 45+1=46 at 2124cm-', and 61+72;=132 at 2041c i d Detailed investigation shows that the relationship"A.RackGround.WT + A.OilVapor = A.OilVapor.WT" istrue at any specific frequency. It means that the absorbancespectra obtained by W T contains both the absorbance of thesample geses and that of thc background gases in thespectrometer.

Fig. I O compared the shape of the peaks by WT and byreal background divided: they are exactly consistent with each

,2065,94 ,2041,131

2150 2100 2050Wavenumbers (cm~l)

Fig.12Absorbanoe Spffitra of Different GainsFig. 1 and Fig. 12 are comparisons of spectra of differentgains. Different gains have changed the sigal level of th e

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transmittance (as shown in Fig. I I ) , hut their absorbancespectra are almost exactly the same (as shown in Fig. 12).Different infrared throu ghpu t has the same effect['61. Theseresults confirmed that the absorbance spectra is independenton the specific spectrometer. Hence that FTIR spectronieter isfree of quantitative calibration. One set of standardquantitative absorbance spectra can be used by anyspectrometer. Although the standard spectra library are notestablished yet, the principle is already there.

111. CONCLUSIONSInvestigation shows hat all the ch aracteristic peaks needed

to be analyzed can be covered if the measurable wavcnumber

[9] Qiplng Yang, Wude Xuc, and Zhi& Lao: "Application o f Gas Sensor nTransformer On -L ine Monitoring:' Tramformer,Vol. 38(2), pp36-38,Feb. ? O O i . (In Chinese).I101 Haoyang W u, Bingguo Chang, Chnngchun Zhu: "Gas Sensor ArraySystem for Analping Fault in Transformer," J. of Xz'm J iao lOngU m w s i ~ ,ol . 32(4), pp2;-25, Apr. 2000. (In Chinese.)1111 Brian Sparling, "Managing the life of trannformors", "RCM forSubstation, Transmission and Dis ~h ut io n onference", [Online] Feb l7 - I 9 ,1999 . Available: h n p : / / ~ . g e p o w e r , c m l S y ~ ~ t ~ ~ i ~ ~ l ~ r t i ~ i ~ . h ~1121 Hui Wang, Xiuge Zhao, and Wendei Xiao: "Quantitative Analysis ofMuitikomponent with FTIR and i t s Application", Jorirnal of EarlC hi no Univemny of Science and Technology, Vol. 27(1), ppl-5, Feb.2001. (In Chinese.)

1131 Jie Zhao, Yongbing Pan, Honglei Li , and Dsngming Xiao, "The Study ofNP W Transformer Online Monitoring System", High VoltageEngineering, Val. 2 6 ( 6 ) ,pp20-2l&p70,?002. (I n Chinese.)1141 Jianbo Can, Dongcheng Hu , "Detection of Exhaust Gas Using No nBackwound Fo wi w Transform Irafrared S ~ e c t r a " , ComPulers Bregion of the spectrometcr is 720cm.'- 3400cm-', and the ApplredChemrsiry, Vol. 17(5), pp2 51-? 56,2 000. ~(h hinese.)1151 Jianbo Gao, Dongoheng Hu : "Qunntitative analysis of the infnredOptimum Optical length Of the gas is around 150mm. ~ p r t r u m u s i n g avelet transforms and arti f icial neu ral ne t wo rw ,LComparative results denionstrates that absoiption spectra Tsi ng Huo Universrg iSci&Tech) ,Vo l . 4 1 ( 3 ) , p p l Z I - l 2 4 , M a r . 2001. (I n

obtained hy wavelet transmission are consistent to those withspectrometer. It is concluded that such a monitor can beconstructed using FTIR that can precisely detect all thediagnostic gases except hydrogen and are free of consuminggases as well as in situ calibration. These researches and the

Chinese.)[I61 Xianyong Liu, "Research on constnxting on-line monitors for dissolvedMeohano-Electronics Engineering, Beijing Institute of Tcchnology,Beijing.China, 2002. (I n Chinese.)

their real back ground divided and are independent on gas-in-o i~fpwer transformers with FTIR: Ph.D. d i d a t i o n , School of

VI. BIOCRWHIESmaturing of FTIR technology in many fields make. itpromising to realize on-line simultaneous measurements ofdissolved gas-in-oil both efficiently an d economically. Andthis will contribute a lot to the promotion of on-linemonitoring and fault diaguosis of powcr transformers.

IV . ACKNOWLEDGMENTThe authors gratefully acknowledge the contributions of

Yuan Hongfu, Wu Huizhong, Wang Baihua, Ren Wei andWu K en s for their assistant on exoeriments in this document.

I l l

I51

I61

171

and worked as en IT nptwork engheer'in Legend Group. His special f ie ld ofintercst inolude on-line monitoring, fault diagnosis, an i f i c ia l intelligence, androffwsrcprogramming.

V. REFERENCESZhcnyuan Wang: "Arti ficial Intolligcnre Applications in the Diagnosiso f P o m r Tramformer Incipient Fnults," ph.D. disser ts t ion, VirginiaPolytechilio Institute and Slate Univcrsity, Blacksburg Virginia in U.S.A.,2000.Li Yang, Yong Shm g, Zhang Yan, 'Trend of Condition-bascd-Monitoring of Paner Transformer Abrond, High VoilagaEngineering, Val. 25(3) , pp37-39, Sep. 1999, (In Ch in as ) .Ruijun Jia, "Review about gas dissolved in transformer oi l on-linedetection", Power System Technology, Vol. 2 ? ( 5 ) , pp49-55, M a y 1998.(In Chinese).Guanjun Zhang, Zheng Qim, and Zhang Yan: "Applirnt ion andDevelopment of DG A Teehnaiogr for Insulation Fault Diagnosis ofPomr Transformers", Transformer, Vol. 36(1), ~ ~ 3 0 - 3 4 ,an. 1999. (In.Chinese).Gesyprotec: "Managing transformers by Key fault Gases On-LineMonitoring; 2000, [online]. Available:h l t p : / l \ w . g e p o w ~ . E o m / S y p r o t e c / i ~ ~ l ~ ~ ~ l e s . h ~ lDouglas Ritohie, "The Opportunities Presented by On-lineTramformer Gas Monitoring," [online].Available:hnp:Iluuw.sprveron.comThomas, W aters, Kristin Williamson, Dr . Douglas Ritchie, "OnlineMeasurementsof Trnnsformcr Fault Gases As Measured Dirertiy i nthe Hedspsre and in the Oil; [online]. Available:http:liul\w.serveron . a m .Jacques Aubin, Brian Spr l hg , AhmedGlodjo, "Field Erprimre WithMultigasOn-Line Mo n i t o r i n g O f Power Transformers," [onlincl.Available: h t t p : l / u u z v . g e p o w P r . r a n i S y p r o t c d i n f o i a r t l ~

Zhou Fan& wa s bo m in Zhejiang, China, onOct. 1964. He graduated from University of Scieocc& Technology Beijlng and acquired his masterdegreethereh1988.

His employmmt experience inc luded l h cRobotios Center in Beijing I n d b t c ofTechnology,B e i j h g S a m i o n g Electric Co. Limited. BeijingLigong MadmElccttio Equipment Co. L k i t e d an dNingbo Online Monitoring Systems Co. Ltd.. Ningbo,Zheiiana. His special ficldr of interat indude..I.'.,.'. .. . h p - -7 ., . ;I automated test, s t&s monitoring and fault diagnosis.H i s studies arc mainly Eoncerned \Mth the fault- . ,. .slnulalion, m-line monitoring and fault diagnosis of power @ansformen.

Mechanics Deprtment of &i j ing Institute ofTechnology (BIT) and becamc a PbD there in 1993.His employment experience inoluded the specialprofessorship fm dcstorial students i n B I T , Ihepresident of Mechano-Eleolronic S c h m l of BIT. Ul edirector of he National Key Lab on Revcntion andControl of Explosion Disasters. He awarded thespcoial professaship of "Enwuragement Plan forChangiiang Soholars" of Chinese govmmenl in

2001.. Hi s s p e d &I& f infcrcst inolude the dynamic characteristics ofmatPriaIS, explosion damages and the prevmlion an d mntml of wplosiondisasters.

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