Equipment. Spot Network Equipment Contents

Transcription

1 September Sheet 00 Spot.0- Equpment Contents Dscusson Spot Decson Tree General Descrpton Commercal Spot Desgn Consderatons Protector Equpment Lqud-Type Transformers Dry-Type Transformers CM Protectors Protector NPL Fuses MPCV Relay Communcatons Capabltes MPCV Relay Communcatons Communcatons Confguratons CM Protector Schematc Dsconnect Cabnet Transton Box to Busway Ratng Selecton Selector Gude Protector Applcaton Informaton Layout Dmensons Lqud-Type Unt Dmensons Dry-Type Unt Dmensons Dry-Type Unt Swtchgear Mounted Protector Dmensons Specfcatons See Eaton s Product Specfcaton Gude, avalable on CD or on the Web. CSI Format: Secton Secton CM Protector 0 CA0000E

2 .0- Dscusson Spot Decson Tree September Sheet 00 Contnuty of Servce Crtcal Consderng Spot s for Electrcal Dstrbuton n a Faclty? Contnuty of Servce NOT Crtcal 0 Does the local utlty offer multple crcuts for the metered utlty servce? YES NO Are the multple ncomng crcuts from the utlty n synchronzaton? YES NO Are the multple crcuts from the utlty the same voltage and frequency under most operatng condtons? YES NO Use Radal desgn at one or more servce voltages. Use separate Radal or Double-ended Substatons wth Open Transton Swtchng. Spot s may be possble, but wthout the redundancy of multple prmary crcuts. How many crcuts are avalable or routed to each major load areas of the faclty? One () Two () Three () Four () Spot s may be possble, but wthout the redundancy of multple prmary crcuts. Three Transformer Spot s are practcal. See Pages.0- through.0- for Applcaton nformaton. If antcpated load = Y kva, use three network transformers each rated Y/ kva. Two Transformer Spot s are practcal. See Pages.0- through.0- for Applcaton nformaton. If antcpated load = X kva, use two network transformers each rated X kva. Four Transformer Spot s are practcal. See Pages.0- through.0- for Applcaton nformaton. If antcpated load = Z kva, use four network transformers each rated Z/ kva. Fgure.0-. Spot Decson Tree CA0000E

3 September Sheet 00 Dscusson General Descrpton.0- Descrpton Eaton s Spot Systems are desgned to ensure servce contnuty n /V and 0/V wye connected secondary network systems. These systems, n ether grd or spot network form, are commonly used n areas of hgh load densty such as metropoltan and suburban busness dstrcts or facltes. Suburban loads were formerly almost entrely resdental and power outages caused lttle more than personal nconvenence. Now, the suburban load ncludes not only shoppng plazas, ndustres and resdences, but such vtal facltes as hosptals and arports. For these and other crtcal loads, power nterruptons can have serous consequences to publc and personal safety. Spot networks provde superor relablty at these mportant loads. The need to supply ncreasng amounts of power effcently, wthout ncreasng equpment sze, has resulted n a shft from V to 0V wye systems. The change to a hgher utlzaton voltage requres a commensurate change n operatng procedures because of the dfference n arcng characterstcs at 0V compared to V. For example, whle an arc n a volt system s normally self-extngushng, an arc n a 0V system wll usually burn untl t s nterrupted by an overcurrent devce or untl t totally consumes the arcng materal. Secondary network systems usng Eaton Protectors are among the most dependable n use today. In the event of a fault on a prmary system cable or transformer, the protector opens due to reverse power flow, thus solatng the fault from the network bus and avodng load power dsturbances. Loss of the prmary feeder wll not result n servce outage at the load on the secondary network. The other prmary feeders wll contnue carryng the load untl the faulted cable s repared and returned to servce. The network protector bascally conssts of a specal ar power breaker, a breaker operatng mechansm, network relay(s) and control equpment. Unts are avalable n both weatherproof and submersble enclosures for ether separate or transformer throat mountng. Swtchgear mountng s also possble. Prmary Crcut Transformer Protector Optonal Man, 0/ Relayng and/or Dsconnect LV Feeder Fgure.0-. Typcal Confguraton for Three Transformer Spot Better Contnuty of Servce The largest user of network systems n the Unted States s Consoldated Edson of New York. Hstorcal data developed by ths utlty llustrates that outages are very rare (approxmately zero) on grd systems and that spot network systems are fve tmes more relable than secondary selectve double-ended substaton servces. Improved Regulaton Less Voltage Saggng Each load s suppled from at least two drectons. Servces suppled from a transformer locaton have a mnmum of two paths of supply on utlty grds and spot networks, and can be desgned to have more. Abrupt changes n loads, such as motor startng, cause much less voltage dsturbance due to the multple paths for load current compared to smple radal servces. The voltage dp resultng from a gven startng current may be 0% less n a network system than n a radal system. Less Transformer Capacty Requred Customer Loads Fuses Te NC In normal operaton, the loads along the network servce are dvded among the varous network transformers n such a way that the best possble voltage condtons and lowest losses are realzed. Snce all the servces are ted together, many more loads are suppled from the same secondary network source than n a smple radal system. The peak loads on the transformers are correspondngly lower n the network system compared Customer Loads Te NC Customer Loads to a radal system supplyng the same loads, because of the dversty n the demand among the larger number of crcuts. Therefore, less transformer capacty may be requred n a network system than n a radal system n the same area, partcularly f three or more prmary feeders supply the network system. System Operaton Typcal Feeder To Other s Low Voltage Swtchgear Drawout A short crcut on any one prmary feeder wll cause all the network protectors on that feeder to open on reverse energy, provded the total power on the three-phase feeder s n the reverse drecton. When the feeder cable s repared properly, the network protectors on that feeder wll automatcally reclose when the feeder crcut breaker at the upstream swtchgear s closed, f correct voltage condtons exst at the network transformer. If the phases are reversed durng the cable repars, the protectors wll not reclose automatcally as long as the network remans energzed. Lkewse, f a voltage less than network voltage s restored to the feeder, the network protector on that feeder wll not reclose automatcally. The unt could be closed manually f the network relay trp contact s not closed. If a feeder from a networkable source s to be connected to an energzed network, the ncomng voltage must be slghtly hgher than the network voltage and n proper phase relaton wth t. If a feeder s beng connected to a dead network, t s suffcent to have the ncomng voltage hgh enough to operate the closng mechansm. 0 CA0000E

4 .0- Dscusson General Descrpton September Sheet 00 0 Mantenance of prmary feeder crcuts can be accomplshed by openng upstream swtchgear prmary devces one at a tme, thereby openng every protector connected to a gven prmary due to reverse magnetzng currents flowng through each protector served. By openng the prmary crcuts one at a tme, the network loads are not dsturbed. Also, at tmes of lght load, the system can be economcally loaded by dsconnectng some of the prmary crcuts and operatng the transformers at more effcent levels. Although the protectors are capable of openng under reverse magnetzng currents, the openng may be delayed dependng upon the tme delay settng of the network relay. When the load ncreases on the network, other prmares can be brought nto servce by closng the feeder breakers. The assocated protectors on the reactvated feeders wll reclose servng the network f the transformer voltage s hgher than the network voltage by a certan mnmum amount and n the proper phase relaton. The network protector fuses provde backup protecton for clearng faults on the prmary feeder n the unlkely event the protector fals to operate. These meltng alloy or partal range current lmtng fuses are located on the load sde of the protector, and when removed, serve to solate the protector from the network. Numerous protector models are avalable from Eaton and the best product for the applcaton s a functon of the type of system beng desgned: utlty grd (see Fgure.0-) or spot network. Spot network systems (see Fgure.0-) usually use the CM type of protector, whch has mportant safety features not found on earler Eaton or compettor models. Typcal Protector Grd LOADS LOADS LOADS Fgure.0-. Typcal Confguraton for Utlty Grd CM Protector Advantages CM Protector Exclusve Drawout Desgn: Wth postve safety nterlocks, provdes maxmum protecton aganst contact wth energzed components whle dsconnectng the unt for test or mantenance; ensures maxmum safety for operatng personnel. All man current carryng and mechancal operatng components are located behnd a deadfront panel whch mnmzes the possblty of tools or hands beng nserted nto an energzed protector. The drawout unt s operated by a hand-cranked leverng system, whch cannot be engaged unless the crcut breaker s open and cannot be dsengaged unless the drawout unt s ether fully dsconnected or fully connected. Modular Constructon: Smplfes feld mantenance and/or replacement of components. Protectors can be quckly LOADS LOADS LOADS Prmary Feeder Breaker LOADS LOADS LOADS Typcal Transformer Grd put back nto servce reducng mantenance tme. Sprng Close Operatng Mechansm: Avods partal closures. The CM sprng close mechansms wll not permt closng moton of the contacts untl the closng sprngs are fully charged. Also provdes close and latch ratngs on protectors. Externally Mounted Slver-Sand Fuses: Operate wth no contamnaton of the protector, and wll postvely nterrupt fault current to dsconnect the protector from the network bus n abnormal fault stuatons. Low Energy, Trp Actuator: Provdes relable trppng effort, even when system voltage s not avalable, up to four operatons va remote trppng before rechargng s needed. Close and Latch Ratngs: Ratngs comparable to ar power breakers are readly avalable snce the mechansm s sprng charged, unlke motor operated protectors whch have no close and latch ratngs. Increased Delectrc Strength: CM unts have passed a more strngent delectrc test voltage of 000 Vac compared to the lower value of 0V requred by ANSI standards. Stored Energy Opton: The CM can be provded wred for stored energy. Ths opton charges the closng sprngs after a closure, resultng n a -cycle close after a trp event. Ths s the preferred confguraton for -unt spot networks. CA0000E

5 September Sheet 00 Dscusson Commercal Spot Desgn Consderatons.0- Commercal Spot Desgn Consderatons Ths secton deals wth the varous components whch make up the commercal spot network, ether as a double-ended substaton or multple transformer substaton. The ntent of the dscusson s to gve some basc gudelnes for the selecton of Eaton transformers and network protectors. The major components that wll be dscussed are:. Prmary swtches. transformer types. protectors. Spot network dsconnects. Low voltage drawout swtchgear confguratons. Typcal spot network layouts. Use of current lmtng fuses. devce coordnaton. Medum Voltage Prmary Swtches The ncomng medum voltage feeder may range from 0V to. kv. Any feeder whch has a voltage hgher than. kv should not be consdered for spot network servce because the cable chargng capactance begns to affect the operaton of the network relay response. The prmary feeder enters nto a swtch compartment, whch can be lqud or ar type. The lqud type transformers usually use a specal three-poston, lqud-flled, non-loadbreak prmary swtch, whch has a specal thrd poston for groundng the ncomng feeder cable durng mantenance work on a prmary crcut. Dry-type transformers usually use a two-poston ar swtch, whch omts the thrd poston. Groundng the crcut becomes a manual procedure, f needed, on dry-type transformers. The three postons of the lqud type non-loadbreak swtch on lqud network transformers are:. Close. Open. Ground These lqud swtch desgns use electrcal nterlocks that prevent the unntentonal movement of the swtch, wth ether the network protector n the Closed poston or the medum voltage feeder beng energzed. Fgure.0- shows the typcal Prmary Mag- Break Swtch Col # Interlock Open Closed Ground Poston Col # Interlock Transformer Fgure.0-. Three-Poston Prmary Swtch Interlock for Lqud Transformers electrcal connectons for the nterlockng between the prmary swtch, transformer and network protector. Col # and # are electrcal nterlocks whch prevent unsafe operaton of the prmary mag-break swtch. Col # ensures that the protector must be used to break load current before operatng the swtch from closed to open. Col # ensures that the prmary cable must be deenergzed before operatng the swtch from closed to ground. These nterlocks are not necessary on a two-poston ar swtch f t has loadbreak ratngs. Due to ther common use, lqud type network transformers are manufactured wth the three-poston mag-break only swtch ntegral to the transformer. Drytype transformers use the commonly avalable two-poston ar swtch wth specal flcker blades whch gve the ar swtch a loadbreak ratng. The capablty of nterruptng load currents can save tme by not havng to deenergze the feeder. The choce of swtch type s thus dctated by the type of transformer selected for the spot network system. Another consderaton s the necessty to provde prmary overcurrent protecton for each transformer, such as n the form of power fuses. Upstream breakers usually serve two, three or four transformers on ther crcut and thus have the protectve relays set at hgher levels dctated by the entre crcut load, whch sacrfces ndvdual transformer protecton. See Fgure.0- later n ths secton for a specfc example of ths type of stuaton. When dry-type unts are used, one soluton s to add power fuses to the loadbreak swtches. However, ths opton s not easy when lqud types are used unless ar b Protector Interlock logc can vary thus both an A and B auxlary contact s suppled. a Fuses To swtches are added ahead of the ntegral type lqud swtches. Eaton recommends that no more than two transformers be served by a sngle upstream breaker and relay, unless separate fused ar swtches are located ahead of the transformers. If fuses are used anywhere n the prmary crcut, the network protector relays must be capable of trppng under WATT-VAR condtons. New dgtal type network relays have the ablty to confgure ther trppng characterstcs from WATT to WATT-VAR n the feld. Older type protectors havng electromechancal relays should be updated by retrofttng wth the newer relays. If fuses are not present, the standard WATT trp characterstc, whch s standard n the ndustry, s approprate. Each type of prmary swtch uses unque termnatons of the prmary cable. Lqud swtches use a termnal chamber whch s flled n the feld wth a sutable compound to mprove the nsulaton strength of the cables. Ar swtches use mechancal or compresson termnatons wth stress cones. Ar swtches requre more floor space than the ntegral lqud type of swtch, especally snce the depth of the ar swtch s made to match the depth of the transformer. Transton sectons add to requred floor space f hard bus connectons, not cable, are requred. Whereas the three-poston lqud swtch dmensons are no greater than.00 nches (0.0 mm) deep off the end of the transformer and 0.00 nches (.0 mm) n wdth centered at the end of the unt. 0 CA0000E

6 .0- Dscusson Commercal Spot Desgn Consderatons September Sheet 00 0 It s possble to use both types of swtches for lqud nstallatons. Groups of ar swtches can be mounted along a wall to receve and dstrbute prmary crcut power to each transformer. Indvdual power fuses can be mounted wthn the ar swtches. Dry-well mountng of current lmtng fuses n ar cansters accessble from the top or sde walls of the transformer s not recommended. The avalable space wll dctate much of the desgn f suffcent space s not allocated for electrcal system equpment. Prmary swtches accommodate the three-phase conductors and never use a neutral conductor. Most spot networks use delta wound transformers, so there s no need to delver the neutral through the prmary swtch. Any type cable can be used, however the more modern types are easer to handle than paper lead nsulated types whch requre potheads for termnatons wthn the prmary swtch.. Transformer Characterstcs After the prmary swtch, the power s delvered to the prmary wndngs of a network type transformer. The desgn may be lqud- or dry-type, wth lqud types beng more popular from a hstorcal perspectve, due to ther applcaton n utlty systems. However, dry-type desgns are now avalable meetng the ANSI network standards. Most applcatons wthn commercal buldngs desre dry-type desgns due to the desre to avod the fre hazard assocated wth lqud delectrcs. It s mportant to use proper dry-type ratngs whch mmc the overload characterstcs of lqud unts, therefore dry types should be rated for 0 C rse and use Class H ºC total temperature nsulaton materals n VPI desgns or C n cast col desgns. Fans are normally employed to ad the ar coolng durng perods of overloadng, and whch occur durng a sngle prmary outage. Secondary voltages are always 0V wye or V wye. Also, V wye s a common ratng. Prmares are always delta, such as 0V,. kv,. kv, etc. Transformer mpedances should fall wthn the standard ranges ndcated n Table.0-, or else the usual protector nterruptng ratngs may become nadequate. If mpedances drop below these values, the maxmum through-fault may exceed the nterruptng ratng of the protector. Also, the mpedance values among transformers n a spot network should be as close n value to each other that manufacturng tolerances wll allow; ths helps reduce crculatng currents between transformers. Table.0-. Transformer Impedance kva Sze Recommended Z % or greater % or greater Notce that 000 kva s typcally the largest transformer that can be used for network servces, although Eaton can go hgher. As an example, let s assume a twount spot network usng dry-type transformers havng 0 C temperature ratngs. In ths example we calculate that the buldng load wll not exceed kva. Snce we are desgnng the servce as a double-ended network substaton, ether transformer must be capable of carryng the full buldng load of 00A. One choce s to select a 00 kva transformer sze whch has a full load ratng of 0 amperes. However, n specfyng transformers for network servces, the unts can be underszed, realzng that under most condtons both unts are avalable to supply power to the network. When only one s handlng the entre load, t should be consdered an abnormal event that should not contnue ndefntely. For our load of kva, a 000 kva transformer wll supply amperes at % of nameplate ratng, therefore we would select a 0 C rse 000 kva dry-type unt operated at ºC wth fans (% overload capablty) and a protector wth a contnuous ratng of A. In all spot network desgns, the equpment must be szed to handle the load even though one prmary, and thus one transformer, s out of servce (known as a sngle contngency condton) for some perod of tme. The basc desgn constrant s that the load not exceed the maxmum thermal ratng of the remanng unt(s) durng the tme of the sngle contngency. Protector ratngs recommended by vendors, as well as protector crcutry, antcpate the loads and are szed to handle the hgher currents, so the lmtng factor s the transformer. One advantage of lqud desgns s ther large thermal mass whch enables them to handle hgher currents for a longer perod of tme wthout the need for an FA fan ratng when compared to conventonal dry-type desgns. When both transformers are avalable, the 000 kva unts n our example wll only be loaded to % of ther AA base ratng. The transformer wndng confguraton wll depend upon the prmary servce avalable and the type of servce needed by utlzaton equpment comprsng the loads. For the most part, transformers are DELTA-WYE, whch permts the lowest ground relay pckup value for the prmary feeder breaker. Ths type of wndng confguraton also elmnates any zero sequence current n the prmary feeder for load unbalances n the secondary. At hgher prmary voltages, kv through. kv, some use has been made of GROUNDED WYE-GROUNDED WYE wndngs. The advantage ganed s the reducton of overvoltages whch can result f one leg of the unt s de-energzed. The dsadvantage s that the prmary breaker ground relay must be set much hgher because load unbalances and ground faults n the secondary are reflected by zero sequence currents n the prmary crcut. See Pages.0- and.0- for network transformer features.. Protector The network protector can be provded n a weather-proof NEMA housng, submersble or sutable for mountng wthn a low voltage swtchgear assembly. Both the transformer sde (lne) and network (load) connectons of the protector are bus bar whch can accommodate transformer flange connectons and loadsde connectons to cable, busway or swtchgear buswork. protectors are specal selfcontaned ar power breaker unts havng a full complement of current, potental and control transformers, as well as relay functons to protect the ntegrty of the low voltage network bus. Normally, protectors do not have any overcurrent protecton n the forward drecton; f necessary, the 0/ functon can be acheved through the use of remote mounted protectve devces. Fgure.0- llustrates a smplfed dagram of the varous components of the network protector. Note: The symbol for a protector s the ar breaker symbol wth a dot n the mddle. CA0000E

7 September Sheet 00 Dscusson Commercal Spot Desgn Consderatons.0- Protectors have ether rollout or drawout mechansms for easy mantenance. Protectors havng the drawout mechansms, such as the CM type, are comparable to ar power breakers n terms of mantenance and stored energy functons. The older rollout unts use manually dsconnected fuses and lnks whch must be removed from the energzed network bus pror to rollng the unt out of the cubcle for nspecton, testng and mantenance. Detals on protectors are revewed later n ths secton and the recommended spot network equpment ratngs for two, three and four unt confguratons are shown n Tables.0- through.0- that appear on Pages.0- and.0- n ths product secton. The protector load sde contans a network fuse, usually a partal range current lmtng type. The fuses are present as back-up protecton f the protector fals to open properly. These fuses are separately removable, but do not drawout wth the protector mechansm. Commonly, the fuses are located at the top of each protector. The fact that the fuses are located on the network sde means that fuse mantenance requres operators to come nto contact wth lve parts and conductors whch can delver hgh fault currents. A method of easly dsconnectng the secondary of the protector from the network bus, smlar to the confguraton of the prmary, s needed to solate the fuse and protector, thus the need for a network dsconnect.. Spot Dsconnects The multple sources of power to the network bus can create a safety concern on the load sde of each protector. Obvously, each protector loadsde s energzed from the network so long as at least one transformer remans connected. The use of a network dsconnect can provde a degree of operator safety by requrng that the dsconnect be used to dsconnect the protector loadsde from the network before allowng access to network fuses or protector mechansm. Such a dsconnect reduces the lkelhood of contactng lve bus and forces operators to follow a safe procedure pror to any protector mantenance. Accdents nvolvng protectors can be traced to the absence of such devces n customer s facltes and dstrbuton system desgns. Eaton encourages the use of network dsconnect devces, especally n facltes not havng dedcated mantenance staff. Many forms of dsconnect devces are avalable; the specfc choce depends upon several related factors such as protector mountng, use of man breakers, protector type, etc. Three key choces for network dsconnect devces are outlned below. Types of Dsconnects Prncpally, the two types are man ar power crcut breakers wthn swtchgear assembles and non-loadbreak hookstck operated swtches mounted above the protectors n a NEMA cabnet. Regardless of the type used, each dsconnect s nterlocked wth the protector to ensure that the loadbreak protector s used to break and make the load currents. The protector mechansm s rated for at least 0,000 operatons before mantenance and s the best devce to nterrupt normal load currents. Protectors nclude an operatons counter to keep track of the number of operatons. The nterlocks may be keyed type or electrcal control wrng. Refer to Fgure.0- for a typcal one-lne. Man Breakers Man ar power breakers are the safest opton to use as a network dsconnect, however ther nterruptng ratng guarantees proper operaton under all condtons ncludng fault currents. Swtchgear mountng of the man breakers means that the dsconnect devce s the same type of devce as all other overcurrent devces mounted n the assembly, thereby requrng common mantenance and operaton procedures. The mans can be key nterlocked wth ther respectve protectors to ensure that the protectors are opened frst, then the mans are opened and racked to a dsconnect poston pror to mantenance of the protector or crcut devces. Man breakers nclude overcurrent trp unts to provde ndvdual overload protecton for each protector and conductors. Ths protecton s not a normal functon of the network relays and augments protecton generally so long as the trp unt settngs are properly coordnated wth the te and feeder devces. The trp unt protecton does not protect the ncomng cable aganst fault currents such as ground faults or short crcut currents; the sensors are not located at the lnesde of the protector crcut, rather they are at the swtchgear (load) sde thus gvng only overload protecton. The key nterlockng between man ar power breakers and network protectors may be elmnated snce the man s a true nterruptng devce usually rated at or above,000a nterruptng at 0V. When mans are used as loadbreak devces on network servces, the openng of a man may result n the openng of the respectve protector, however mantenance procedures should always verfy protector operaton. Non-Loadbreak Dsconnect The network dsconnect devce for mountng above the protector s the non-loadbreak bolted pressure swtch. The devce s hookstck operated from the floor and provdes a relable means of vsbly dsconnectng the protector crcut from the loadsde of the protector. The swtch s NEMA cabnet mounted wth double doors and electrcal nterlocks to assure that the protector s used to break the load current. The door nterlocks have a defeatable procedure f qualfed personnel need to gan access under load flow condtons. Key nterlockng wth the protector s not necessary. 0 CA0000E

8 .0- Dscusson Commercal Spot Desgn Consderatons September Sheet 00 0 Protector Fuses Protector Loadsde () MPCV = Protector Relay Transformer Fgure.0-. Typcal Protector Schematc Cont. Lnesde (Transformer) LV SWGR kv or kv Prmary o 0 Wye 0/ Fgure.0-. Partal Spot One-Lne Dagram Recommended when no separate man breaker s used. Ths product has become a standard for Eaton and s manufactured n the same plant as the protector for mproved assembly and product coordnaton. Recent desgns move the NPL fuses on the protector nto the dsconnect cabnet to ensure that fuses have controlled access. Space exsts wthn the cabnet to mount separate current transformers to provde nputs for separate nstantaneous and tme delay overcurrent relays whch protect the protector crcutry from pont of supply to the swtchgear buswork. The General Servces Admnstraton uses ths type of product on hundreds of network unts throughout the Natonal Captal Regon and n other areas of the country where networks are used. Potental Transformer (PTs) 0V Control Txs. Cts MPCV Phasng Voltage PTs V V Ground MPCV Trp b a MPCV Voltage Motor Transformer Protector Fuses Dsconnect Swtch (Optonal) Man Breaker NC MPCV Close Trp Te MPCV Trp Cont. The non-loadbreak desgn has been chosen over the loadbreak for several reasons. Frst, the loadbreak mechansms need regular mantenance and should not be allowed to st n a closed poston for years, then be called upon to operate wthout falure. Ths type of duty s exactly what s requred of a network dsconnect. Addtonally, the operatng mechansm of a loadbreak desgn requres a lot of force, more than an operator can safely delver from a ladder or step. Hookstck operaton from the floor s a safer procedure. Refer to Fgure.0- for typcal secton vew of network unts usng a network dsconnect atop the protector. transformer neutrals are brought to the loadsde area of the dsconnect for transtonng to the protector crcut neutral for delvery nto the swtchgear. The loadsde of the dsconnect can accommodate outgong busway or cables as needed. See Page.0- for network dsconnect features. 0/ Relayng for Protectors Users who specfy the non-loadbreak dsconnect can easly add the current transformers for relayng at the load sde of the protector crcuts and provde superor fault and overload protecton for the ncomng conductors between the protector and the swtchgear buswork. The relays are usually mounted wthn the swtchgear and use a lockout feature to trp and lockout the protector. Modern mcroprocessor relays such as the Eaton Dgtrp 000 can also be used for the 0/ protecton to save costs and mountng space. The use of forward relayng on the protector crcut needs to be coordnated wth the te breakers to ensure that the protector auxlary 0/ protectve settngs are not faster than the te settngs. Coordnaton s acheved when the tes are faster actng than the 0/ protector forward overcurrent relays, and they usually trp open frst due to the presence of multple transformer faults passng through the tes. See Fgures.0- and.0- for more detals. Also refer to tables on Pages.0- and.0- for detals on the recommended te devce ratngs and settngs. The use of forward relayng current transformers s recommended even when the non-loadbreak dsconnect s not used, such as occurs when only transton boxes are used at the top of the protectors. System Neutral Groundng Regardless of the devce selected as the network dsconnect, the XO transformer neutrals are not grounded at the transformers. Rather they are brought nto the swtchgear and grounded at one and only one locaton. Ths confguraton allows the use of the ground return method of ground fault protecton whose zone of protecton extends from the secondary transformer wndngs to the outgong ar power breakers n the swtchgear. Other ground fault detecton methods are possble, but are consderably more complcated to wre and mantan and are wthout sgnfcant advantage or greater relablty. CA0000E

9 September Sheet 00 Dscusson Commercal Spot Desgn Consderatons.0-. Low Voltage Drawout Swtchgear Confguratons The most relable and safe network bus equpment s n the form of low voltage drawout swtchgear bult per ANSI C standards. Unlke the UL swtchboard assembles, low voltage swtchgear uses true 0,000A braced buswork, 0 cycle short tme ratngs, drawout stored energy ar power crcut breakers rated for 00% applcaton, for easer mantenance all of whch provdes superor performance compared to fxed mounted molded case breakers n swtchboard constructon. Ths s true regardless of where the protector s mounted. A typcal swtchgear nstallaton of a protector uses a low voltage swtchgear compartment whch s.00 nches (. mm) hgh x.00 nches (. mm) wde x nches (.. mm) deep. The use of transton sectons between the protector and swtchgear ensures that suffcent space exsts to route buswork between the two compartments. Refer to Fgures.0- through.0- whch llustrate typcal plan vews and front elevatons for double-ended network substatons and three transformer spot network desgns. Fgure.0- shows the bus confguraton of the two-unt spot network substaton. Note that there must be a separate ground return neutral bus whch has only one pont of connecton to the groundng conductor. Ths type arrangement permts selectve trppng of the Te, then the protector. For a lne-to-ground fault on Bus #, the T lockout relay controllng the Te breaker wll be operated frst when GFR-T detects.0 per unt ground current. After the Te breaker s open, the lne-to-ground fault current s sensed only by GFR-, whch wll actuate the - lockout to trp the network protector NP #. For prmary faults, the network relay must be set such that t can respond to both reverse magnetzng levels of current as well as to any prmary crcut fault current. Snce most systems employ DELTA-WYE wndngs, prmary faults wll not be detected by ether GFR-T or the GFR devces assocated wth the protectors, snce no zero sequence current wll flow. However, f GROUNDED WYE- GROUNDED WYE transformers are used, the relay coordnaton must be such that the network relay responds frst to prmary feeder faults. Ths permts the correct operaton of the protector under such condtons, CA0000E Prmary Swtch Neutral Bus Neutral (XO Bushng on Back) Transformer Fgure.0-. Typcal Non-Loadbreak Dsconnect Mountng Arrangement because the GFR-T should not attempt to trp the Te open. Therefore, power wll be mantaned on the low voltage bus wth the Te breaker remanng closed. See Fgures.0- and.0- for layout arrangements for dry-type and lqud-type spot networks respectvely. Fgure.0-0 shows the bus confguraton for a three-unt commercal spot network. Agan, the ground return neutral bus s requred whch has only one pont of connecton to the groundng conductor. Selectve trppng s acheved n the same fashon as the double-ended network substaton wth GFR-T sensng ground current and operatng the T devce whch then opens both Te breakers. The ground relays GFR-, GFR- and GFR- wll only sense ground current after the Te lockout s energzed and the Te breakers are open. Interlockng auxlary contacts on the -T wth the GFR crcuts guarantees ths selectve trppng and ensures the user that ground currents are accurately measured. The ampacty of the ground return neutral bus must meet the mnmum requrements of the neutral bus. It s prudent to sze the ground return neutral bus the same sze as the phase bus, snce the ground and neutral carry fault currents durng abnormal events. The space requred by the ground sensors and connectng buswork can be accommodated easly n two-unt spot networks. However, on threeand four-unt systems, the extensve structure-to-structure nsulated ground bus plus the normal phase, neutral and ground buses can reduce the usage of four breaker cells n the Load Transton Non-loadbreak Dsconnect NEMA Cabnet Fuse Locaton (Insde) Protector (CM Type) Secton Vew swtchgear to three. Vendor desgns vary on ths ssue. All four breaker cells are avalable on two-unt, threeunt, and four-unt systems from Eaton, when Magnum DS swtchgear s used. The ampacty of the phase and neutral buswork must meet the gross demand plus spare capacty for growth as stpulated by the Natonal Electrcal Code for the loads served. If each transformer on a two-unt spot network has been szed wth 00% redundancy, then each protector and load buswork should be rated to carry the entre load from one prmary feeder and one transformer. Threeunt spot networks can reduce the redundancy to 0% for the same loads snce two unts reman n servce. Four-unt spot networks may reduce the redundancy to %, unless the loads need to be served from two remanng servces n whch case 00% redundancy s stll requred.. Typcal Spot Layouts The amount of space avalable for the electrc servce wll dctate the sze and quantty of the network unts chosen for a project. Double-ended substatons, especally dry-type desgns, tend to be arranged n a sngle lneup wth the prmary feeders located at opposte ends of the room. Refer to Fgure.0- for an example of ths type of arrangement. The sngle lneup can be used f space permts. One alternatve s to locate the transformers behnd, or n front of the swtchgear, wth nterconnectng busway or cables. 0

10 .0-0 Dscusson Commercal Spot Desgn Consderatons September Sheet 00 0 Loads Fgure.0-. One-Lne for Two-Unt Spot Protectors not fused. -Poston PRI SW. (Fuse) PH. A,B,C N Feeder Breakers Transformer Fgure.0-. Front Vew of Double-Ended Substaton Three or more transformer unt spot networks cannot be arranged n one lneup, therefore they use the remote mountng of the transformers. Refer to Fgure.0- for an example of ths type of equpment layout. It s mportant to remember whch sde or end of equpment s used for normal operatons when desgnng a network layout. The prmary swtches are operated from the end as are the protectors. Swtchgear needs both NEC clearances at the front and the rear, due to the drawout breakers and the rear accessble cable compartments. Desgners are encouraged to pay attenton to the dfferent voltage levels present, both medum and low voltage, and the requred workng clearances gven n the NEC or local codes. N.P. # N.P. # - - 0/ 0/ GFR- Protector FDR FDR FDR FDR FDR FDR FDR FDR NC Te -T Te GFR-T FDR FDR FDR FDR FDR FDR FDR FDR GFR- GRN (Ground Return Neutral) Protector PH. A,B,C Feeder Breakers Equpment weghts should also be nvestgated to ensure that the structure can support the network assembles. Means of egress and routes to remove materal f replacement becomes necessary should be dentfed. Avod placng any network equpment aganst any wall; the NEC clearances requred probably double f two means of egress are not avalable. Structural columns pose challenges, however they rarely defeat network arrangements; avod swtchgear door openngs bumpng aganst columns before they are fully opened. The hghest pece of equpment may be the low voltage swtchgear, whch s usually.00 nches (. mm) n heght, plus the nches N Loads Ground Bus Transformer -Poston PRI SW. (Fuse) (..0 mm) requred by a ral mounted top of gear breaker lfter devce, or the network dsconnect, and must be accommodated. Lqud transformer unts have very hgh core and col untankng heghts, whch precludes any chance of untankng the core and cols n a normal buldng. See Fgures.0- through.0-. Regardng conductors, t s prudent to remember that busway can enter or ext a swtchgear structure at only one locaton. Room does not exst to accommodate more than the frst run of busway n a sngle secton, unless the frst connects at the top and the second connects at the bottom. A typcal plan vew for a three-unt spot network s shown n Fgure.0-; four-unt spot networks are smlarly desgned. If t becomes necessary to splt the swtchgear assembly, poston the splts at one sde or the other of the Te devces. Ths approach smplfes the power connectons of the neutral and ground buses. The number of network transformers used n a typcal spot network s drectly correlated wth the number of ndependent, yet networkable prmary feeders avalable. At least, that s a general rule to follow, however the secondary equpment can take many confguratons. Eaton recommends usng at least one normally closed te breaker n the low voltage metal-enclosed swtchgear for the purpose of solatng ground faults, and for mantenance of the assembly (cleanng, torqung and testng). Usually the number of normally closed Te breakers equals N-, where N equals the number of transformers used n the spot network. However, for some projects t may be desrable to have a rng low voltage assembly where the number of Te breakers equals N. In such a rng spot network, a Te busway or cable connects the extreme left sde bus of the assembly to the extreme rght sde bus, thus keepng the N- network confguraton even when one prmary or network transformer s down, or the low voltage assembly bus s down for mantenance or fault solaton. Man breakers, when used, may be postoned n swtchgear that s one ntegral lneup, or mounted n swtchgear close-coupled to dry-type transformer/protector pars whch feed power crcuts to remote assembles havng all Te and Feeder breakers. CA0000E

11 September Sheet 0 Dscusson Commercal Spot Desgn Consderatons.0- Hstorcally, some users and desgners have recommended usng low voltage busway as the spot collector bus, then feedng loads radally from the collector bus. Eaton does not recommend low voltage busway as the network collector bus, snce t has lmted short-tme ratngs and has hgher falure rates than the more robust low voltage metal-enclosed swtchgear. It s certanly acceptable to use multple segments of busway to feed protector crcuts nto the swtchgear, where the redundancy of busway crcuts prevents loss of power to loads for a sngle busway fault or falure, and the avalable fault currents are lmted to levels that can be delvered by one transformer, not N transformers. Control voltages for network protectors are usually Vac and derved nternally from the transformer secondary or wthn the protector tself, thus protectors are self-contaned regardng control power. The low voltage swtchgear assembly may be ac or DC wth AC control power beng more popular. The ac current control systems use a control power transformer on the ncomng of each protector crcut wth a control power transfer system on the secondares of all control power transformers to pck the frst lve source. The control power crcuts are always energzed so long as at least one protector s closed. The addton of man meters for power montorng, overcurrent relays and communcaton trp unts generally take very lttle space and can be accommodated wthout addng space f the swtchgear layout rules and standards are followed. It s possble to montor other non-swtchgear equpment by addng space for the requred number of communcatng addressable relays whch montor remote contacts wred to the swtchgear for status and alarmng at a remote power montorng and control system, such as transformer temperature and pressure alarms.. Use of Current Lmtng Fuses Generally, ths ssue needs to be addressed n the desgn stage of a project, pror to specfcaton wrtng. Protectors are usually appled wth fuse lmters on the load sde of each protector, but there can be exceptons to usng the lmters. The expected fault currents need to be calculated for several locatons, ncludng secondary wndngs of transformers, network swtchgear bus (both sdes of PH. A,B,C Loads N N.P. # N.P. # - - 0/ 0/ NC NC PH. A,B,C Te Te GFR- Feeder Breakers -T GFR-T Fgure.0-0. One-Lne for Three-Unt Spot Protectors are fused for three- and four-unt spot networks. Fuse locaton. Fgure.0-. Floor Plan for Three-Unt Spot System Te breakers), and at the load sde of feeder breakers. systems that use ar power breakers and delver more than,000a of fault current should use feeder breakers such as Eaton s Magnum DS breakers rated up to 00,000A. protectors are normally equpped wth load sde fuses (usually partal range current lmtng) and serve as backup protecton should the protector fal to open on reverse fault current condtons. Ar power breakers are now avalable wth kaic ratngs of,, 00 and 0 kaic, wthout fuses. GFR- Feeder Breakers Loads Ground Bus FDRS Aux. Aux. Aux. Sectons Te FDRS Sectons Te FDRS Sectons N N 0/ PH. A,B,C GFR- N.P. # - Loads GRN (Ground Return Neutral) Prmary Swtch Transformer Protector Busway or Cable Low Voltage Drawout Swtchgear In two transformer spot networks, one can argue that the protectors do not need to be fused for any applcaton up to and ncludng 000 kva transformers. The prncpal logc s that the Te can experence only the fault current from one transformer and that the Te protectve trp settngs provde faster actng backup protecton than the protector fuses for reverse power condtons. When protector fuses are used, the system needs to be desgned wth nterlockng to ensure that the fuses are not accessble unless the protector and dsconnect are opened. N Feeder Breakers 0 CA0000E

12 .0- Dscusson Commercal Spot Desgn Consderatons September Sheet 0 0 Transformer Fgure.0-. Floor Plan for Double-Ended Substaton # Protector Fgure.0-. Example of Two-Unt Spot Coordnaton Issues. Devce Coordnaton By way of example, we shall llustrate the level of coordnaton possble n a typcal two-unt network system as shown n Fgure.0-. In ths example, two networkable prmary sources are avalable and several transformers are presumed to be fed from each of the two prmary crcuts. The upstream prmary devce s a. kv vacuum crcut breaker wth a complement of relayng. Protector Aux. Aux. Sectons FDRS Te FDRS Sectons 0/ Prmary Medum Voltage Devces Two Poston Fusble Prmary Swtch 000/00 kva Dry Transformer AA/FA A CMD Non-Fused Protector 00A Te NC Typcal DS or DSL Feeders # Transformer Busway or Cable Tray Low Voltage Drawout Swtchgear E CLE Fuse 0/ To Other Spot s The medum voltage swtches are fused ar type. The swtches have two postons, open and closed, not three postons. We recommend that the prmary swtches use key nterlocks wth protectors to ensure that the protectors are used to break and make load currents, although ths nterlockng s not absolutely necessary snce the swtches are loadbreak rated. The lack of a ground poston n the prmary swtches does not mpede the normal operaton of the network system; rather t makes groundng the prmary cable a manual procedure. In ths example, a two-unt network wth 000/00 kva dry transformers AA/FA, 0 C rse are used. The transformers are confgured delta-wye wth. kv prmary, a 0V wye secondary, and the mpedance of each s wthn the range of..00%. Eaton Type CM Protectors are rated A and are mounted wthn low voltage swtchgear structures. The CM s a deadfront, drawout protector whose operaton s very smlar to the ar power crcut breaker used throughout the swtchgear to dstrbute power to the outgong crcuts. The network relay used wthn the CM s the MPCV type, a mcroprocessor-ntegrated sold-state relay that allows for feld programmng the network characterstcs. All CM protectors are factory wred for applcaton of remote trp and lockout functons, whch wll be used n our example va the lockout relay and separate 0/ protectve relay. The 0/ relay wll use 00/ rato current transformer nputs from current transformers mounted on the load sde of each protector wthn a transton box. The 0/ devce may be a sold-state relay, Dgtrp 000, due to ts broad range of feld programmable settngs. Thus, the protectors are used as man overcurrent protectve devces as well as protectors. When transformers are remote from the swtchgear, the current transformers must be located wthn a transton box atop the protectors. The current transformers may be used for meterng also, or f more accurate meterng at lower current levels s desred then a second set may be necessary n the swtchgear wth mult-ratos to match the average load demands. The low voltage assembly uses Eaton Magnum DS breakers for both Te and Feeder devces. The Te breaker wll be an MDS-, 00A frame, 00A trp, electrcally operated, drawout desgn, ncorporatng the Dgtrp trp unt. The feeder breakers are a mx of 00A frame and 00A frame to serve the outgong feeder crcuts. The swtchgear wll panel mount the two 0/ relays, whch provde overcurrent protecton for the protectors. In ths example, the fault currents are less than ka; however, systems havng hgher fault currents can be accommodated usng hgher-rated Magnum DS breakers. CA0000E

13 September Sheet 0 General Dscusson Coordnaton Curves The protectve devce settngs for a two-unt spot network are smlar to those used for a standard doubleended substaton. The goal s to serve both contnuty of servce and protecton equally. Settngs should not favor ether one or the other, but rather should keep loads served f at all possble and mnmze nusance outages even under serve fault condtons, ncludng ground fault events. Bascally, settngs should be mplemented whch allow the closest upstream devce near a fault to clear before other upstream devces trp. Faults n a network have more than one source, whch s a major dfference compared to double-ended substatons wth a normally open Te breaker. In Fgure.0-, we plot the tmecurrent curves of the medum voltage power fuses, whose man functon s to provde short crcut protecton to each transformer, the ANSI damage curve typcal for the transformers, the 0/ relayng upstream from each spot network, the Te and Feeder devce trp curves, and the 0/ relayng used by each protector. We have shown the prmary 0/ protectve relayng curves by postulatng ther relatve poston as beng to the rght of each damage curve and to the left of prmary cable damage curves, snce several transformers are served by each prmary servce. In other words, several vault locatons exst n the faclty. Obvously, these prmary relays cannot protect each transformer ndvdually, nor s t desrable to do so snce t s better to solate a smple faulted transformer wth a power fuse than to open the entre prmary crcut. The followng paragraphs detal the protectve devce settngs, dscuss the curves, and revew the mportant ssues. ANSI Transformer Damage Curves Two curves are plotted: both the 00% and the % damage curves are shown for the dry types n our example. These curves are defned n ANSI Standard. The % curve reflects the fact that a one per unt secondary fault on a grounded wye transformer creates a 0. per unt fault n the prmary conductors when the prmary wndngs have a delta confguraton. Dscusson Commercal Spot Desgn Consderatons TIME 00 Legend: Fgure.0-. Two-Transformer Spot Phase Overcurrent Eaton CLE E Power Fuses The selected current lmtng fuse, E, provdes lttle f any overload protecton for the transformer, however, t does an acceptable job of supplyng NEC code mandated short crcut protecton for the 00% damage curve. The fuse cannot provde protecton for the % curve and downszng the selected ratng lower than E s lkely to result n nusance fuse operaton. Each power fuse vendor has applcaton tables and charts to properly select fuses for any applcaton. The fuse meets the NEC stpulated protecton, but lacks the flexblty of a relay wth nearly contnuous adjustments. If superor protecton s desred, then a vacuum breaker wth 0/ relayng should be used n leu of the fused prmary swtch. Do not use 0/ relayng on a load nterrupter swtch B CURRENT (Amperes) R Prmary 0/ Relayng Typcal for These Transformers T 00% ANSI Damage/Wthstand Curve for Transformer T % ANSI Damage/Wthstand Curve F Power Fuse E Ratng P Protector Relay 0/ (Both LTD = 0 Seconds and Seconds Shown) T Te Breaker 00AT MAG = TX INRUSH B Feeder Breaker 00AT MAG = TX INRUSH T MAG R P T T F MAG CA0000E

14 .0- Dscusson Commercal Spot Desgn Consderatons September Sheet 0 0 Protector Relayng Eaton Dgtrp 000 Plus Ground Fault Relay (GFR) relays do not have any form of forward 0/ (nstantaneous and tme overcurrent) protecton, therefore f t s desred t must be added separately. An lockout relay s recommended for postve lockout ndcaton and reset operatons. The curve for the Dgtrp 000 s shown n Fgure.0- and depcts the settngs for ths mcroprocessor-based soldstate mult-phase relay. Usng the 00/ rato current transformers, the settngs are as follows: Long Tme Pckup (LTPU) =.0 (00A) Long Tme Delay I t (LTD) = 0 seconds Short Tme Pckup (STPU) = X (000A) Short Tme Delay (STD) = 0. seconds Instantaneous (INST) = X (00A) Ground Fault Relay (GFR) Ground Fault Relay (GFR) = 00A pckup = 0. seconds ( cycles) It s very mportant that the protector 0/ settngs be slower than the Te breaker. The faster actng Te s desred for solaton of swtchgear faults between one sde of the Te and the loadsde of a protector wthout takng the whole network down. The Te clears one transformer s fault contrbuton, whle the unfaulted sde remans energzed. The protector experencng the remanng fault current wll subsequently trp open, thereby solatng one-half of the network bus for repar. Faults located n the transformer secondary wndngs may open both the Te and the protector, dependng upon the magntude of the event. The protector should open frst upon reverse power, snce protectors respond to reverse power n cycles. If the Te also trps open, the Te can be reclosed to serve the entre load agan after lockng out the protector on the faulted transformer. Note: The transformer s gven superor overload protecton by the Dgtrp 000 compared to the level of protecton gven by the power fuse. Ths s especally true even n the overload regon of the ANSI damage curve. Te Breaker Eaton MDS 00A wth Dgtrp LS Plus Ground Fault Relay The settngs shown n Fgure.0- were developed usng 00/ sensors on the Te breaker. The settngs recommended are: Long Tme Pckup (LTPU) = 0. (00A) Long Tme Delay I t (LTD) = seconds Short Tme Pckup (STPU) = X (00A) Short Tme Delay (STD) = 0. seconds Instantaneous (INST) = Not used Ground Fault Relay (GFR) Ground Fault Relay (GFR) = 00A pckup = 0. seconds ( cycles) See Fgure.0- These settngs allow the Te to act quckly for abnormal current condtons, yet also provde enough delay to allow protectors to trp on reverse current when protector operaton s the prudent frst course of acton. Also, larger feeder devces, such as 0A breakers (not shown n Fgure.0-) wll easly ft to the left and beneath the Te curve. It s mportant to set the Te to operate qucker than the protector 0/ relayng. The faster Te settngs assure that swtchgear bus faults do not take the entre servce down (only half). In our example, the Te wll only be called upon to nterrupt the fault current from one transformer. Typcal Feeder Eaton MDS 00A wth Dgtrp LSIG The settngs n Fgure.0- were generated usng 00/ sensors appled on the feeder breakers. The Dgtrp trp unt settngs are: Long Tme Pckup (LTPU) =.0 (00A) Long Tme Delay (LTD) = seconds Short Tme Pckup (STPU) = Not used Short Tme Delay (STD) = Not used Instantaneous (INST) = X (00A) Ground Fault Pckup (GFPU) Ground Fault Delay (GFD) = F (00A) = 0. seconds ( cycles) See Fgure.0- These settngs provde for fast acton of feeder devces experencng the maxmum fault duty of the swtchgear (fault current from two transformers). Ground fault protecton s recommended for the feeder trp unts; these settngs can be coordnated wth the two-stage ground fault detecton system (sngle pont ground return method) mentoned earler n Fgure.0-. Suggested ground fault protectve devce settngs are llustrated n Fgure.0-, and the settngs are lsted under the protector, Te breaker, and feeder devce dscusson n ths secton. CA0000E

15 September Sheet 0 Ground fault settngs are establshed essentally the same as a double-ended substaton usng a sngle tee ground pont and ground return methodology. Eaton s MDS feeder breakers are set to coordnate wth downstream devces so that downstream breakers experencng a fault trp frst. The GFR relays for the Te and protectors are set slghtly hgher n pckup and have a longer delay than the ground fault for the feeder devces. Protector and Te ground fault settngs are usually set at the same levels; coordnaton s acheved by nterlockng the two stages so that the Te stage operates frst followed by the protector stage. Ground current orgnatng from faults n the swtchgear buswork or ncomng conductors s drectly measured by the GFR on the Te, then by one of the protectors after the Te opens. Subsequently, the GFR on the faulted zone causes the protector experencng the fault to trp open thereby solatng the fault completely. Downstream ground faults are cleared by downstream crcut breakers or the DS feeder breaker servng the faulted crcut. Dscusson Commercal Spot Desgn Consderatons Fgure.0-. Spot Ground Fault Protecton.0-0 CA0000E

16 .0- Protector Equpment Lqud-Type Transformers September Sheet 0 0 Lqud-Type Transformers Typcal Lqud Transformer transformers are avalable wth lqud mmersed core and col assembles, and use the lqud as the prncpal nsulaton means for prmary and secondary wndngs. The flud can be mneral ol, slcon or a bodegradable form of vegetable ol. Indoor applcatons beneft from usng slcon or the bodegradable vegetable ol lqud delectrc. See the dscusson below for ABB s BoTemp flud. The transformers are bult to ANSI C..0 standards and have an ntegral prmary non-loadbreak threeposton swtch havng connected, open and grounded postons. The grounded poston grounds the ncomng medum voltage feeder that serves the transformer, and does not ground the prmary wndngs. The prmary swtch s nterlocked wth the assocated network protector and secondary transformer wndngs to ensure that the swtch s only used to break or make magnetzng current. Lqud network transformers have a specal low voltage flange for feld mountng a network protector on the secondary flange. The protector s best mounted close to the secondary wndngs of the assocated transformer to mnmze dstance between the wndngs and the protector contacts. There are only two standard ANSI flange confguratons, smaller and larger, and the user generally gets one based upon the transformer kva sze. It s possble to chose one over the other, but the specfer must be careful n the selecton and make certan adequate load growth and redundancy are bult nto the system when choosng a small flange sze for a transformer that normally s suppled wth a large flange for a hgher ampacty protector. If the specfer stays wth the Eaton recommendatons for szng protectors, the flange sze s properly chosen for every unt. Lqud transformers are avalable wth an array of accessores, most of whch are lsted on the next page wth the outlne drawngs of a typcal lqud network transformer. Alarm contacts are usually wred to termnal boxes for use on alarm schemes or montorng. Certan accessores allow for the samplng of fluds at regular mantenance ntervals for testng and analyss. Table.0-. Typcal Propertes of Insulatng Fluds Descrpton BIOTEMP Mneral Ol H.T.H. Slcone Electrcal Delectrc strength, kv (ASTM D) 0 0 Physcal Vscosty, cst. 00 C 0. (ASTM D) 0 C 0 C Flash pt. C (ASTM D) 0 00 Fre pt. C (ASTM D) Specfc heat (cal/gr/ C) (ASTM D) Coeffcent of expanson, / C (ASTM D0). x 0. x 0.0 x 0.0 x 0 Pour pt. C (ASTM D) to 0 Sp. gravty (ASTM D) Color (ASTM D00) < <0. Envronmental Bodegradaton Rate (%) day CEC L BoTemp Advantages BIOTEMP s a natural ester flud made from renewable and bodegradable vegetable-based ol. Below are some of the envronmental, fre safety and operatonal advantages of usng BIOTEMP. Envronmental Advantages Even though secondary contanment s stll requred, BIOTEMP splls can be dsposed through normal means and not treated as hazardous or toxc waste BIOTEMP mnmzes ar polluton by producng only carbon doxde and water durng combuston BIOTEMP also offers the potental for relef from government regulatory penaltes, resultng n less costly spll cleanups Fre Safety Advantages BIOTEMP offers greater rsk mtgaton on collateral damage from transformer exploson and fre, potentally lowerng nsurance premums Actve fre suppresson and barrer walls can essentally be elmnated wth BIOTEMP when mnmal spacng s mantaned BIOTEMP can alternatvely be used safely ndoors and n tghter spaces outdoors typcally wthout addtonal fre safety requrements BIOTEMP s lsted as a less flammable delectrc flud by Factory Mutual (FM Global) and s classfed as a less hazardous delectrc medum n respect to fre hazard by Underwrters Laboratores (UL) Operatonal Advantages BIOTEMP mpregnated paper experences a much lower agng rate compared to mneral ol mpregnated paper, leadng to an ncrease n the nsulaton system lfetme (grd relablty) BIOTEMP mpregnated paper can alternatvely operate at a hgher hotspot temperature and attan the same lfe expectancy as mneral ol mpregnated paper, ncreasng the transformer peak load or overload capacty (energy effcency) CA0000E

17 September Sheet 0 Protector Equpment Lqud-Type Transformers.0- Sealed Tank Braced for PSI (0 KPA) Color Black. Base-Bar Type 0. (.0) x.0 (.0). Jackng Areas Total. Lftng Hook for Lftng Complete Transformer. Welded Cover wth Gasket and Lftng Loops for Lftng Cover Only..00 (.) Fllng and Upper Flter Connecton. Bolted Manhole.0 (.0) x.0 (.0) Openng wth Cortte Gasket. Relef Devce Over a.00 (.0) Handhole. Cap wth.00 (.0) Square Head for Access to De-energzed Tap Changer (wth Key Interlock, Coordnated wth HV Swtch). Item. LV Throat Per ANSI C..0 Fgure. LV Bushng Total. XO Bushng Style DG0 Spade. (.0) NEMA Drlled.. (.0) Wde x 0. (.0) Thck Spade..00 (.) Dran Valve wth Bronze Ppe Plug. Ground Pads -Hole NEMA Drllng 0 Total. Magnetc Lqud Level Gauge wth Alarm Contacts. Vacuum Pressure Gauge wth Alarm Contact and Ar Test Valve. Lqud Temperature Gauge wth Alarm Contacts. Rapd Pressure Rse Relay. Control Cabnet wth Undrlled Entrance Plate. Bolted Manhole.0 (.0) x.0 (.0) Openng wth Cortte Gasket. H.V. -Poston Magnetc Break Dsconnect and Groundng Swtch Operatng Mechansm wth Provsons for Padlockng, wth Key Interlock. Locked n Open or Ground Postons, Coordnated wth Tap Changer. Item and Second Key Interlock. Locked n Closed Poston and Coordnated wth Low Voltage Protector..00 (.) Fllng Couplng. Magnetc Lqud Level Gauge. Swtch Postons Top to Bottom, Ground, Closed, Open. Swtch Cover wth 0.0 (.) Taps for Jack Screws (Bolted on). Termnal Chamber Cover wth 0.0 (.) Taps for Jack Screws (Bolted on). Nameplate and Warnng Plate. H.V. Termnal Chamber..00 (.) Dran Couplng. Termnal for # to /0 Cable Range Total..00 (0.) Over Tank.00 (.) To XO.0 (.) To Cab XO.0 (.).0 (0.).0 (.).0 (.0) Over Swtch Entrance.00 (.) Entrance G & W Stuffng Boxes. Catalog Number RS-G,.0 (.0) CL to CL. 0.0 (.) Ar Test Fttng wth Bronze Ppe Plug. 0.0 (.) Top Lqud Sampler wth Bronze Ppe Plug. 0. (.0) Flud Level Plug. Interlock Bushng. 0.0 (.) Overall & Shppng Length.0 (0.).0 (.) CL Tank.0 (.0) To Swtch Entrance) Plan Vew X0.0 (.) X X X.0 (0.).00 (0.) Centerlne LV Throat.0 (.) Overall & Shppng Length. (.) Shppng Heght 0.0 (.).0 (.).0 (.).0 (.).0 (0.0).0 (.) Base Length.0 (0.0) Sde Vew Fgure.0-. Outlne Drawng 0 kva, / C Rse,,0 Delta to 0Y/ Volts Front Vew CA0000E

18 .0- Protector Equpment Dry-Type Transformers September Sheet 0 0 Dry-Type Transformers transformers are avalable wth dry-type core and col assembles, and use specal polyester resn or cast epoxy as the prncpal nsulaton means for prmary and secondary wndngs. The choce depends upon the economcs of the project. Indoor applcatons beneft from usng drytype networks snce no contanment or samplng of lqud delectrc s needed. Eaton strongly recommends 0 C rse cast col transformers for use n spot network systems. Typcal Dry-Type Transformer The transformers are bult to ANSI C.. standards and do not have an ntegral prmary swtch, unless a two-poston swtch s added n the feld. The process of groundng the ncomng medum voltage feeder that serves the transformer becomes a manual process of addng groundng cables. The two-poston prmary swtch s usually loadbreak rated and s not nterlocked wth the assocated network protector and secondary transformer wndngs. Eaton can also supply close-coupled prmary swtchgear wth a two-breaker (VCPW) transfer capablty on the prmary of cast col dry-type network unts. The proxmty of vacuum breakers wll mandate usng RC snubbers wthn the transformer. Dry-type network transformers have a specal low voltage flange for feld mountng a network protector on the secondary flange. The protector s best mounted close to the secondary wndngs of the assocated transformer to mnmze dstance between the wndngs and the protector contacts. There are only two standard ANSI flange confguratons, smaller and larger, and the user generally gets one based upon the transformer kva sze. It s possble to chose one over the other, but the specfer must be careful n the selecton and make certan adequate load growth and redundancy are bult nto the system when choosng a small flange sze for a transformer that normally s suppled wth a large flange for a hgher ampacty protector. If the specfer stays wth the Eaton recommendatons for szng protectors, the flange sze s properly chosen for every unt. Dry-type transformers can be closecoupled to LV drawout swtchgear wth protectors, te and feeder devces all swtchgear mounted. Dry-type network transformers are avalable wth an array of features, most of whch are lsted on the next page wth the outlne drawngs of a typcal dry network transformer. A transformer montorng package s usually ncluded wth temperature readngs, RTDs and Alarm contacts. Most desgns have knock-down enclosures for ease n rggng a unt nto poston through hallways and doorways. CA0000E

19 September Sheet 0 Protector Equpment Dry-Type Transformers.0- Total of Two Jack Screws 0.0 UN.00 (.) C L 0.00 (.0). (.). (.). (.0). (.0).0 (.).00 (.).00 (.).00 (.). (.).00 (.).00 (.0). (.).00 (.).00 (.).0 (.).00 (.) X X X. (.) TEMPERATURE MONITOR OR CUTOUT PROVIDED NAMEPLATE.00 (.) LV End Vew 0. x.0 (. x.0) Rects. (.) H H H.00 (.) Ventlated Surface Front and Back 0.00 (.) Front Vew X0.00 (.0) 0. x.0 (. x.) Slots. (.).00 (.) HV End Vew.00 (.).00 (0.).0 (.) 0.00 (.0). (.0). (.) 0.00 (.0).00 (.). (.0). (.) Characterstcs Enclosure: NEMA (ndoor ventlated wth drp-proof roof) Fnsh: ANSI Product type: Cast/Cast kva: 000/00 HV:,0 HV kv BIL: LV: 0Y/ LV kv BIL: 0 Taps:,0/,0/,0/,0/,0 Impedance: % Temperature rse: 0 C Coolng class: AA/FA Hertz: 0 Phases: LV wndngs: Cu HV wndngs: Cu Sound level: db Approxmate weght: 0,0/ lbs/kg Provsons for mountng network protector on the left end Prmary s cable connected to closed coupled prmary swtchgear, such as MVS Accessores Braced for sesmc ANSI LV end sheets Standard ventlaton Alumnum screens Copper ground bus (0. x.00) Neutral dsconnect lnk UL lstng Control panel Control power suppled by ABB Forced coolng 0 Fgure.0-. Outlne Drawng 000/00 kva Cast Col Transformer, 0 C/00 C Rse,,00 Delta to 0Y/ Vac Wye CA0000E

20 .0- Protector Equpment Type CM Protectors September Sheet 0 Type CM Protectors 0 Typcal Enclosed CM Protector Qualty Desgned to be Smarter, Safer and Streamlned The CM Protector provdes the hghest level of relablty and servce contnuty avalable today. An ntellgent protectve devce, the CM Protector s desgned to handle ratngs from 00 to 00A, to 00V. Ths new network protector features an electrcally operated, composte case, sprng closed ar network crcut breaker controlled by the MPCV network relay. The CM meets or exceeds the standards n IEEE C... Ths ensures a product wth the hghest performance standard applcable to a network protector. A frst for network protectors, the CM s settng a new standard by beng UL-qualfed. Ths thrd party approval certfes the delvery of a qualty product. A UL-qualfed network protector means easer code approval for qucker system start-up and less approval tme and costs n a non-utlty envronment. UL lsted and labeled CM protectors are presently avalable through 00A. Contact Eaton and the protector product lne for more detals on UL lsted and labeled CM network protectors. Protector Ratngs CM Drawout Several network protector models currently exst to satsfy all locaton requrements. The new CM desgn covers all of these ratngs, gvng you one type of protector to handle all nstallaton needs. The styles avalable nclude nternal or external fuse mountngs and submersble or NEMA enclosures throughout the current and voltage ratngs. Havng parts and accessores common through all protector ratngs means lower mantenance and nventory costs. The CM was also desgned wth hgher nterruptng and fault close ratngs than older protector models. Ths hgher ratng allows for safer nstallatons and better protecton on a network system. Table.0-. CM Ratngs Table Ratngs through 0 Volts Wye Contnuous Current Ratng / 00 00/ Interruptng Ratng Close and Latch Ratng Suggested Transformer Ratng (kva) V 0V CA0000E