TECHBriefs. Underground Challenges

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1 Buns & McDonnell 9400 Wad Pakway Kansas Ciy, MO (816) Alana Chaanooga, Tenn. Chicago Denve Fenon, Mo. Houson Miami New Yok O Fallon, Ill. Phoenix San Diego San Fancisco S. Louis Washingon, D.C. Wichia, Kan. Fo moe infomaion, conac TechBiefs a echbiefs@bunsmcd.com To subscibe, go o Fo addess changes, conac Dala Amsein a damsein@bunsmcd.com 2006 Buns & McDonnell Makeing, Communicaions Challenges ae wha make life ineesing; ovecoming hem is wha makes life meaningful. Joshua J. Maine Pined on ecycled pape TECHBiefs A quaely publicaion by Buns & McDonnell 2006 No. 2 Undegound Challenges Connecicu Bulk Tansmission Pojec Tackles Design, Consucion Issues Unique o Buied Lines By Sco E. Newland, P.E., and Michael E. Beehle, P.E. Connecicu Ligh & Powe (CL&P), a wholly owned subsidiay of Noheas Uiliies, has embaked on a $1.2 billion bulk ansmission pojec ha includes 69 miles of new 345-kV ansmission line. Abou 24 miles of ha will be solid dielecic undegound cable. Even hough CL&P seves only abou 1.2 million cusomes, he Middleown-Nowalk (M-N) ansmission pojec is he lages capial ansmission pojec in he couny (see Figue 1). The pojec, o be compleed in Decembe 2009, also includes seveal new and modified subsaions. Buns & McDonnell is poviding pogam managemen and deailed design o CL&P, which is esponsible fo compleion of 18.5 miles of he undegound ansmission poion of he pojec. Neighboing uiliy Unied Illuminaing is handling he emainde. As pogam manage, Buns & McDonnell is esponsible fo managing all phases of pemiing, land acquisiion, ouing, envionmenal compliance, public elaions, pocuemen, and deailed design and consucion. Pemiing and Land Acquisiion The pemiing pocess involves he Connecicu Siing Council, local municipaliies, he Connecicu Depamen of Tanspoaion (ConnDOT) and envionmenal agencies including he Office of Long Island Sound, Amy Cops of Enginees, Inland Wae Resouces Division of he Depamen of Envionmenal Poecion, and local welands and coasal aea managemen. Pemis equied include local pemis, noise waives, affic conol, dewaeing, soil handling and see opening pemis. The eam is acquiing a Geneal Encoachmen Ageemen fom ConnDOT o esablish he geneal consucion and design consains along sae oads. Buns & McDonnell hied a law fim and sie acquisiion/suvey fim, boh local opeaions, o faciliae land acquisiion. The law fim pepaes he easemen ageemens and leads he condemnaion pocess. The acquisiion/suvey fim negoiaes wih landownes. Easemens ae based on he squae fooage of land equied and is assessed value and ae paid fo by CL&P hough he conacos. Field Invesigaions Buns & McDonnell hied local engineeing fims, geologiss and scieniss o assis wih field invesigaions o deemine consucion Undegound Challenges Connecicu Bulk Tansmission Pojec Tackles Design, Consucion Issues Unique o Buied Lines Demysifying Foecasing Mehods Daa Analysis Pus Uiliies in Posiion o Pedic Gowh Moe Accuaely Impoving Dinking Wae Qualiy Micofilaion and Ulafilaion Membanes Inceasingly Mee Cos and Qualiy Demands

2 consains, geoechnical popeies, locaion of exising uiliies, locaion of hazadous and pollued maeial and a opogaphic and planimeic suvey of he enie oue. The geoechnical invesigaion includes appoximaely 175 boings spaced evey 750 fee along he oue. Themal es enginees wee on sie wih dill igs o acquie hemal samples. The geoechnical invesigaion will assis wih vaul design, ock and wae deph, soil classificaions and hemal esisiviy. Resuls of he geoechnical and hemal esing showed ha 75% of 175 sies had wae and limied ock, alhough bouldes and cobbles wee encouneed. The civil conacos wee insuced o assume no ock in bids, and all ock excavaion would be handled hough allowances. Subsuface uiliy engineeing (SUE) has been pefomed along he undegound oue. SUE is he engineeing pocess ha idenifies, chaaceizes and maps undegound uiliy faciliies. I includes he hee majo aciviies of designaing, locaing and daa managemen. Designaing sevices have been compleed. Designaing is he pocess of deemining he pesence and hoizonal and veical posiion of undegound uiliies using geophysical pospecing echniques. Locaing sevices also have been povided fo he enie oue, including excavaing es holes using vacuum excavaion o compaable nondesucive equipmen a ciical poins along a subsuface uiliy s pah. Aound 800 vacuum excavaions have been pefomed. Splice Vauls Splice vaul locaions ae deemined by cable pulling calculaions, cable eel lenghs, exising uiliies, sysem gounding mehod, locaion of ock, and locaion of wae and aiload cossings. The 8-foo by 8-foo by 30-foo (inside dimensions) vauls (see Figue 2) will be spaced evey 1,700 fee (plus o minus fee) along he 18.5-mile secion(s) of undegound line. ConnDOT equies all vauls be off he avelway unless physical condiions peclude. Theefoe, many vauls ae in he paking los of adjacen businesses. Mos of he oue aveses Roue 1. CL&P will acquie 6,000- o 9,000-squae-foo easemens fo off-see vaul locaions. Lage excavaions of a leas 36-foo by 14-foo by 14-fee deep will be equied fo each vaul. Tidal wae ables flucuae beween 3 fee and 15 fee below he suface. Each splice vaul is pecas, muli-secioned and is waeigh. The vauls ae appoximaely 30,000 pounds pe secion, and he design vehicle loading has been povided by ConnDOT. The splice vauls ae gounded and conain endbells fo he elecic and communicaion ducs ha will be acked on a single side of he vaul. Cable manufacues specified he inside vaul dimensions based on consucion, mainenance and Naional Elecic Safey Code cleaances. The splice vauls will be supplied by egional pecases using cusom sucual designs and will have 10- o 12-inch hick walls. Duc Bank Insallaion The civil conaco(s) should achieve fee of duc bank pe day pe cew and will un up o vaul and duc bank poducion cews a he peak of consucion. Two o hee suppoing cews will be employed fo uiliy elocaion, epaving and ock coing o beak up he minimal ock ha is expeced wihou blasing, which he pemis pohibi. The minimum size of he duc bank is 4 fee by 4 fee and cuves o avoid ees, som dains, sewes, foundaions, ec., ha incease pulling ensions and final cable lenghs. Insallaion includes saw cuing he oad, excavaing he ench, expoing he spoils, placing 20-foo lenghs of 8-inch PVC conduis in spaces, encasing he ducs in 2,500 psi concee, Figue 1: The Middleown/Nowalk pojec coves nealy 70 miles, mosly along Roue 1. TECHBiefs 2006 No. 2 2 Buns & McDonnell

3 Sco E. Newland is he engineeing manage and pojec manage fo he 345-kV undegound ansmission poion of he Middleown-Nowalk pojec. He gaduaed fom he Univesiy of Nebaska-Lincoln in 1999 wih a bachelo s degee in civil engineeing. He has been he lead enginee on seveal EPC and convenional engineeing undegound ansmission lines. Michael E. Beehle is a dieco of business developmen fo Buns & McDonnell. He gaduaed fom he Univesiy of Aizona in 1981 wih a bachelo s degee in civil engineeing. He eceived his MBA fom he Univesiy of Phoenix in He held vaious ansmission engineeing posiions a he Tucson Elecic Powe Co. and he Hawaiian Elecic Co. He is a egiseed pofessional enginee in eigh saes and is a fellow in ASCE and a membe of IEEE. Fo moe infomaion, please snewland@ bunsmcd.com o mbeehle@bunsmcd.com Figue 2: A coss-secion of a splice vaul. backfilling he ench wih a hemally esed flowable fill and laying a empoay biuminous pach. The concee and flowable fill will undego hemal esing and slump esing. Fluidized Themal Backfill (FTB) is a diggable concee of psi ha allows hemal hea o escape fom he enegized conducos inside he duc bank, minimizing cable deaing. Afe he FTB is placed 9 inches below he suface, he civil conaco applies a class 1 and class 3 asphal concee ho mix as a empoay pach. Upon compleion of he duc banks, he civil conaco will poof he inegiy of individual PVC ducs by a oboic video check, swabbing and mandeling. Swabbing involves unning a ball of ags hough he ducs o look fo eas and mandeling pulls an 18-inch wooden plug, sized 1/8 inch smalle han he inside diamee of he duc, hough he ducs o deec bus, flaws, ec. ha would damage he jacke of he cable. The civil conaco poofs he ducs wih a swab and mandel and hen insalls a mule ape o show he exac lengh of he individual duc bank wih all he veical and hoizonal cuves in place. Befoe cable pulling, he elecical conaco will eswab and mandel he ducs. Cable Pulling and Teminaions Buns & McDonnell will pe-qualify and selec hough compeiive bidding one manufacue fo each cicui of he 345-kV solid dielecic cable wih a guaaneed wo cable manufacues on he pojec. The successful manufacues will be hied unde a funish and insall conac using one o moe lage U.S.-based elecical conacos. The cable fo he M-N pojec is a 3,000 kcmil 345-kV coss-linked polyehylene (XLPE) engineeed, cusom poduc joinly specified by CL&P and UI. Thee cables made of coppe, epoxy, insulaion and lead sheahing, and weighing 29 pounds pe foo, makes a single cicui of 345 kv ha will cay up o 860 MVA. Maximum allowable pulling ension on he 3,000 kcmil cable is appoximaely 22,000 pounds, bu aveage ension duing consucion will be abou 15,000 pounds. Coninuous pulls ae impoan o he elecical conaco, and majo challenges occu if he is equied o sop in he middle of a pull. Conduis ae lubicaed wih a soap-like sluy poduc o lowe he coefficien of ficion fom 0.3 (dy) o as low as 0.1 (opimum). Conclusion Pogess hough ealy 2006 has been good, bu many consucion challenges lay ahead. Onschedule compleion of he undegound segmen of he MNP by summe 2009 will equie he use of all civil engineeing disciplines. The effo is echnically one of a kind, and one of he mos ineesing pojecs in he hisoy of he powe delivey indusy. Buns & McDonnell TECHBiefs 2006 No. 2

4 Demysifying Foecasing Mehods Daa Analysis Pus Uiliies in Posiion o Pedic Gowh Moe Accuaely By Jon Summeville The Rules of Foecasing: Pa I Foecasing is vey difficul, especially if i s abou he fuue. Similaly, he momen you foecas you know you e going o be wong. You jus don know when, in which diecion and who will emembe. Foecasing The pas is nomally he bes pedico of he fuue. Thee ae hee basic mehods of using he pas o pedic he fuue: univaiae (using pas paens wih such mehods as moving aveages and ends), mulivaiae (using pas elaionships beween muliple vaiables fo example, egession analysis), and qualiaive (using subjecive judgmens and ohe infomaion). All ae commonly acceped mehods unde he igh cicumsances. Mulivaiae foecasing is he pimay mehod used in developing load foecass due o he song associaion ha nomally exiss beween he dependen and independen vaiables. Fo example, he elaionship beween he numbe of a uiliy s esidenial consumes (he dependen vaiable) and he numbe of esidens in a sevice aea (he independen vaiable) is vey song. Mulivaiae foecasing also ends o be moe accuae in he inemediae o long un. Daa Collecion Daa collecion is one of he mos cucial seps in he developmen of an economeic foecas. Availabiliy of daa is a majo consideaion in he selecion of vaiables fo use in developing foecasing models. Boh hisoical and foecas daa fo a paicula vaiable mus be available if ha vaiable is o be used in he modeling pocess. Fuhe, hee is ofen a ime lag fo hisoical daa availabiliy. Some daa ae available quickly, wheeas ohe daa may no be available fo six o 12 monhs. Accuae and imely daa ae essenial o he developmen of a ealisic load foecas. Regession Analysis Regession analysis is one of he mos widely applied saisical mehods of modeling imeseies daa. I is he saisical echnique in which he hisoical vaiaion in one vaiable (he dependen vaiable) is explained saisically by he hisoical vaiaion in one o moe ohe vaiables (he independen vaiables). This is a way in which o model cause and effec. Fo example, when he populaion of a coopeaive s sevice aea inceases, he numbe of esidenial consumes inceases. Two vaiables may have a high coelaion, howeve, wihou being causally elaed. Thus, i is necessay o undesand he naue of he dependen vaiable in ode o selec he appopiae independen vaiable. Applicaion of egession analysis yields saisical esimaes of he magniude and diecion of he hisoical elaionship beween he dependen and each independen (explanaoy) vaiable. A popely specified explanaoy model, o egession equaion, can be used o pedic fuue values of he dependen vaiable a given values of he explanaoy vaiables by assuming hese elaionships will coninue. Qualiaive (judgmenal) mehods mus also be included unde appopiae cicumsances, such as when company saff has inside infomaion egading lage cusomes o specific geogaphic aeas. This inside infomaion can gealy enhance he adiional foecasing appoaches. Equaion Esimaion/Validaion The coefficiens of each equaion ae esimaed using a muliple egession compue pogam (SPSS) ha employs he mehod of odinay Fuhe Sudy Fo a moe deailed discussion of he vaious mehods of foecasing, efe o Foecasing Pinciples and Applicaions by Sephen A. DeLugio (Iwin McGaw-Hill, 1998). TECHBiefs 2006 No. 2 Buns & McDonnell

5 o o o o o o o o o o o o o o o o o o o o o o -saisic. This is compued by compaing he coefficien of he vaiable (β) o is sandad eo. The specific value of a paicula -saisic equied fo saisical significance depends on boh he degees of feedom (he numbe of daa obsevaions less he numbe of vaiables) of he equaion and he desied level of confidence in he esimaed coefficiens. In geneal, howeve, he -saisic should have a magniude of a leas 2.0 fo a 95% level of confidence, and a leas 1.5 fo a 90% level of confidence. Figue 1: An example of unceainy analyses on sysem demand scenaios. Jon Summeville is an analys in he Business & Technology Sevices Goup of Buns & McDonnell. He has a bachelo s degee in business adminisaion and an MBA in finance fom he Univesiy of Kansas. Fo moe infomaion, please jsummeville@bunsmcd.com leas squaes. Each of he esuling equaions should be subjeced o a few basic saisical ess fom which a pefeed equaion can be seleced. Regessions can also be pefomed in Excel using he Daa Analysis ToolPak add-in. A simple bu impoan cieion is ha he coefficien of each explanaoy vaiable has he coec sign. Fo example, enegy sales will geneally incease as a consume s income inceases o duing peiods of colde o hoe weahe (i.e., hese vaiables should have posiive coefficiens). Convesely, enegy sales geneally decease wih inceasing eleciciy pices. An impoan es is how well he equaion explains he hisoical vaiaion in he dependen vaiable. The coefficien of deeminaion (R-squaed) is he popoion of he vaiance in he dependen vaiable Y ha is explained o eliminaed hough he elaionship wih he independen vaiable X; ha is, how much of Y is explained by vaiaions in he independen vaiable. An R-squaed value of 1.0 indicaes ha all of he vaiaion is explained, wheeas an R-squaed value of 0.0 indicaes ha none of he vaiaion is explained. Geneally, an equaion wih an R-squaed geae han 0.80 is consideed o be saisically adequae in explaining hisoical vaiaion, assuming he ohe validiy measues ae accepable. Each of he explanaoy vaiables should have a significan influence on he dependen vaiable. In a simple linea egession analysis whee hee is only one explanaoy vaiable, he saisical significance of his vaiable is measued by he One final elemen mus be consideed in developing a valid equaion: Quie simply, he equaion mus make sense. Independen vaiables chosen o explain he dependen vaiable should no be acceped based on good saisical esuls alone. An equaion wih good saisics will no be useful if he dependen vaiable does no logically elae o he independen vaiable. Fo example, a saisically valid model ha elaes he success (o lack of success) of he Kansas Ciy Royals o he numbe of esidenial consumes would no be accepable. Thee is no easonable elaionship beween baseball and enegy consumes. Load Foecass and Powe Requiemens Sudies (PRS) Load foecass ae equied annually by evey elecic uiliy and coopeaive, and he Buns & McDonnell Business & Technology Sevices Goup has subsanial expeience pepaing load foecass. Specifically, he Rual Uiliies Sevice equies powe supply and disibuion boowes o mainain an appoved load foecas (PRS) on an ongoing basis. This can be achieved by submiing a new load foecas evey 36 monhs wih annual updaes, o submiing a new load foecas evey 24 monhs. The Rules of Foecasing: Pa II Always be pecise in you foecass. Fo example, many economiss sae hei GNP gowh pojecions o he neaes wo decimal places jus o pove hey also have a sense of humo. Finally, when pesening you foecas, give hem a numbe o give hem a dae, bu neve boh. Buns & McDonnell TECHBiefs 2006 No. 2

6 Impoving Dinking Wae Qualiy Micofilaion and Ulafilaion Membanes Inceasingly Mee Cos and Qualiy Demands By Mak Lichwad, P.E. In ecen yeas, micofilaion (MF) and ulafilaion (UF) membanes have become a viable alenaive o convenional filaion in wae eamen faciliies. This can be aibued o a significan educion in coss as well as he need fo impoved wae qualiy o mee moe singen egulaions and eplace aging infasucue. No only ae membane sysems becoming cos-compeiive and poving eliable, hey can also povide a moe consisen finished wae qualiy han convenional filaion. Advances in Membane Pocesses MF/UF membane pocesses use hollow fibe membanes wih poe sizes anging fom 0.02 o 0.2 μm. These hollow fibe membanes have elaively low opeaing pessues (~7 40 psi) and a high suface aea o volume aio. The fibes ae made of polymeic maeials ha ae olean o low/high ph and oxidans, which allows fo aggessive chemical cleaning of he membanes and povides flexibiliy in opeaion. Advances in membane pocesses ove he pas decade have esuled in he following benefis: Consisen finished wae qualiy Posiive baie o waebone pahogens (including Giadia lambia and Cypospoidium) Highly auomaed opeaion Cos-compeiive when compaed o convenional filaion Long-em compliance wih egulaions Smalle foopin han convenional eamen The consisency of he finished wae qualiy in a ypical membane plan is shown in Figue 1. Tubidiy, which povides a measue of he claiy of wae, can flucuae subsanially in wae eaed by a convenional eamen plan based on he aw wae qualiy and effeciveness of peeamen. Howeve, wih membane echnologies, he finished wae ubidiy will emain elaively consan. Membane Sysem Configuaions The mos common configuaions fo MF/UF membanes in dinking wae eamen ae pessue and immesed membane sysems. While he configuaions of he membane sysems vay, he opeaion is elaively simila, wih ouine backwashing and chemical cleaning being conduced a specified inevals. The hollow fibes in a pessue sysem ae conained in a pessue vessel, and he wae is foced hough he membane. This can be advanageous in siuaions whee he feed wae is aleady unde pessue. In an immesed (o submeged) sysem, he membanes ae submeged in a wae ank o file basin and wae is dawn hough he membane fibes by a vacuum. Figue 1: Membane pocesses povide consisency in finished wae qualiy despie flucuaing aw wae ubidiy. TECHBiefs 2006 No. 2 6 Buns & McDonnell

7 Municipaliies implemening peeamen wih membane echnologies ofen ealize a significan educion in he capial cos of he membane equipmen, as well as a educion in opeaion and mainenance coss. This configuaion ypically equies a smalle foopin han a pessue sysem. Theefoe, boh of hese sysem configuaions have disinc advanages in ceain applicaions and boh should be consideed fo specific pojecs. Opimizing he Design and Opeaion To povide he mos cos-effecive and opeaofiendly design, opimizaion of he membane sysem design is ciical. Consiuens ha cause membane fouling (o blockage of he membane poes) mus be managed by opimizing he opeaion, and if necessay, peeamen should be included in he design. To opimize boh he design and opeaion, pilo esing is highly ecommended. Membane Peeamen Since he pimay pupose of MF/ UF membanes is paiculae emoval, chemical addiion pio o he membanes is geneally equied o achieve emoval of specific conaminans. Peeamen using apid mix, flocculaion and sedimenaion can incease he capaciy of a membane sysem and impove membane pefomance by significanly educing oganic and/o inoganic fouling consiuens in he membane influen. Specifically, hese pefomance enhancemens include inceases in membane flux and ecovey, as well as lenghened cleaning inevals and exended membane life. As a esul of hese pefomance enhancemens, municipaliies implemening peeamen wih membane echnologies ofen ealize a significan educion in he capial cos of he membane equipmen, as well as a educion in opeaion and mainenance coss. The educion in membane capial cos is due o he inceased membane flux and ecovey since fewe membanes ae equied o achieve he same capaciy. Likewise, he educed opeaion and mainenance coss ae a esul of chemical and labo savings associaed wih lenghened cleaning inevals. A seveal of he membane faciliies ecenly compleed by Buns & McDonnell, he savings in membane coss wee geae han he cos of adding peeamen, making peeamen he economically pefeed opion. Pilo Tesing A popely conduced pilo esing pogam can povide valuable infomaion egading he pefomance and opeaion of a membane sysem, and can allow fo a side-by-side compaison of seveal membane sysems. This infomaion can be used o calculae life cycle coss and povide a fai and compeiive pocuemen envionmen. The pilo esing pogam fo he MF/UF sysems should be developed o opimize and demonsae he pefomance and opeaion of each sysem esed. I should povide infomaion ha can be used o deemine he design cieia fo he fullscale plan. Theefoe, he pilo esing should be conduced in condiions simila o hose expeced in he full-scale plan. Boh cold and wam wae opeaing condiions should be deemined and esed if feasible. Alhough vaious mehods can be used fo pilo opimizaion, ypically membane flux is held faily consan, while he ansmembane pessues (TMPs), pecen ecovey, fequency of evese filaion/backpulse and ohe opeaional paamees ae adjused o opimize opeaion and pefomance of each sysem. Specific asks ha should be included in a pilo pogam include ubidiy spiking, opimizaion of pefomance, pefomance demonsaion phases, veificaion of inegiy esing, monioing of cleaning efficiency, a deailed monioing and sampling poocol, monioing of finished wae qualiy, and qualiy assuance/qualiy conol measues. Evaluaion of vaious coagulans and cleaning chemicals can Buns & McDonnell TECHBiefs 2006 No. 2

8 Figue 2: Buns & McDonnell ecenly eofied he Columbine Wae Teamen Plan in Thonon, Colo., wih submeged membanes o incease he capaciy fom 28 million gallons pe day o 50 MGD. also be incopoaed ino he pogam o fuhe impove membane pefomance and educe opeaional coss. Reofiing Exising Faciliies Fo many exising faciliies, he eofiing of membanes ino exising file basins can be a cos-effecive soluion fo meeing new micobial and ubidiy emoval equiemens while simulaneously upgading plan equipmen. (See Figue 2.) Capaciy of he plan can ofen be inceased wihou building eniely new faciliies. Alhough hee is a poenial fo cos savings ove consucing new faciliies, hee ae seveal issues o addess ha should no be ovelooked in he pedesign phase of a eofi pojec. These include modificaions o he file basins o accommodae membanes and placemen of he equied ancillay equipmen. Depending on he membane sysem implemened, ancillay equipmen could include blowes, ai compessos, vacuum pumps, auomaed saines, aw wae pumps and pemeae pumps. In addiion, since chemicals ae equied fo cleaning of he membanes, addiional chemical feed and soage faciliies ae ypically equied. Implemenaion of Membane Pocesses MF/UF membanes povide an aacive alenaive o convenional eamen boh in cos and benefis. They can be implemened in new and exising faciliies, and can ofen incease he capaciy of an exising plan wihin he exising foopin. While he design of a membane eamen sysem can be complex, a welldesigned sysem can povide ease of opeaion in addiion o impoved wae qualiy. Opimizaion of he design hough a deailed pilo pogam and he design of effecive peeamen can educe oveall pojec coss and povide he bes value o he owne. Mak A. Lichwad, P.E., is he wae supply depamen manage in Buns & McDonnell s Denve office. He has 14 yeas of expeience in wae supply and eamen wih an emphasis in advanced eamen echnologies. He eceived his bachelo s and mase s degees in mechanical engineeing fom he Univesiy of Coloado. Fo moe infomaion, please mlichwad@bunsmcd.com TECHBiefs 2006 No. 2 Buns & McDonnell