IFB 18-06 Transformer Addendum 2 - Huntsville Utilities...modified by this specification, shall be...
Transcript of IFB 18-06 Transformer Addendum 2 - Huntsville Utilities...modified by this specification, shall be...
Huntsville Utilities IFB 18-06 Transformer BidAddendum 2
A. Reminder for bid extension.1. The new bid due date is March 27, 2018 at 2:00 CDT PM.
B. Updated Specifications1. EED 105.39.7_2_22_18 (name correction-not attached)2. EED 105.39.8_2_22_18 (name correction-not attached)3. EED 105.39.9_2_22_18 (name correction-not attached)4. EED 105.15.4_12_20_175. EED 105.39.10_12_20_176. EED 105.39.11_12_20_17
C. Questions/Exceptions from Specifications
Please note Addendum(s) on proposal packets.
H u ntsville Utilities IFB 18 -06 TransformerB idA d d end u m 2
1. Stand ard warrantywillbe in effect.Stand ard warrantyis acceptable provid ed itmeets orexceed s warrantyprovid ed in H u ntsville Utilities bid package.
2. Stand ard packinglistwillbe provid ed .Stand ard packinglistis acceptable provid ed itmeets ou rspec whichcalls foraweatherproof tagind icatingH u ntsville's commod ity nu mberand P O to beattached to the transformer.
3. M ay we no qu ote anyitems whichexceed ou rcapability/capacity,ormu stwe qu ote everyitemin agrou p? The blanketwillbe award ed in grou ps i.e.overhead ,single phase pad mou nt,threephase pad mou nt.If there are anyline items in agrou pthatare no bid byavend or,H u ntsvilleUtilities reserves the rightto award thatgrou pminu s those line items to the respective vend or.
4. N o ind ication thathighvoltage taps are requ ired .Is thatcorrect?Y es.Transformers withhighvoltage taps willbe specialord eritems.
5. M ay we provid e ou rstand ard pressu re relief valve ratherthan qu alitrol?H u ntsville Utilities willrequ ire the specified qu alitrolvalve.
6. W hatis H u ntsville Utilities’d rawingrequ irements? Stand ard approvald rawings are generallyacceptable.If you thinkthere is somethingwe may requ ire thatyou d o notprovid e pleaseprovid e asample d rawingforevalu ation.
H u ntsville Utilities E lectricalE ngineeringD epartmentS ingle-P hase,O verhead,D istribu tion TransformerS pecificationsS ingle V oltage and D u alV oltage S pecifications D ated S eptember2012
1.Section 9.3,Item # 9,requ ires the externald imensions to be provid ed on C TR.H owardInd u stries onlyprovid es exteriord imensions on sales & approvald rawings.W e d o notpu td imensions on C TR.W illthis be acceptable to H u ntsville Utilities?This is acceptable.
2.Section 17 .1 (single voltage)& Section 16.1 (D u alvoltage)requ ire eachtransformerto besecu red to the palletwithtwo steelband s.W e u ses plastic band inginstead of steelband ing.P leaseconfirm if this is acceptable.H ighstrengthnylon orsimilarmaterialis acceptable.(per2007 response)
H u ntsville Utilities E lectricalE ngineeringD epartmentS ingle-P hase,P ad-mou nted,D istribu tion TransformerS pecificationsS ingle V oltage and D u alV oltage S pecifications D ated S eptember2012
1.Sections 13.3and 13.7 (single voltage)& Section 13.2 and 13.6 (d u alvoltage)W e wou ld likeapprovalto u se H oward Ind u stries highvoltage and low voltage bu shings forthis bid .H u ntsvilleUtilities granted approvalforthe 200 8 bid forH oward bu shings bu ttheyd id notgetinclu d ed intheirlatestspecs.The H Ibu shingwelland low voltage bu shingsu bmitted forapprovalareacceptable.(per200 7 response)
2.Sections 16.4 (single voltage and d u alvoltage)B othsingle phase pad specs callforstainlesssteelsecu ritybolts.H oward Ind u stries wou ld need to take exception to this requ irement.Ithasbeen ou rexperience thatstainless steelsecu ritybolts willnotpreventgalling.H oward Ind u stries
H u ntsville Utilities IFB 18 -06 TransformerB idA d d end u m 2
provid es silicon bronze secu ritybolts to preventgalling.These have been u sed on allsingle phasepad s bu iltbyH oward Ind u stries since year2000.This is acceptable.
(The above qu estions also applyto the Three P hase P ad -mou nted Transformers as wellas theSingle-P hase P ad -mou nted Transformers)
H u ntsville Utilities E lectricalE ngineeringD epartmentThree-P hase,P ad-mou nted,D istribu tion TransformerS pecificationsS ingle V oltage and D u alV oltage S pecifications D ated S eptember2012
1.Sections 19.1 (single voltage and d u alvoltage)The C ooperC L Fs requ ired bythe specs willsoonbe obsolete.C ooperhas new C L Fs thatwillreplace these.H oward Ind u stries has provid ed theC oopertechnicald atafortheirnew C L Fs (see attached )Und erevalu ation.
2.Sections 14.2 B u shingd esignations,kV A ,P rimaryvoltage,and second ary voltage are requ iredto be stenciled on the u nits.W illH u ntsville Utilities acceptd ecals? This wou ld allow u s to u sescannable barcod es whichhelps withqu alityassu rance.The exteriorKV A ,P rimaryvoltage,andsecond aryvoltage mu stbe stenciled .A scanable barcod e maybe u sed as well.Interiorbu shingscan be d esignated withd ecals.
3.Spec d ated Sept2012 shows primaryvoltage of 1247 0Y /7 200 in three phase pad specification.EED 105.39/6 revised N ovember16,2004 withprimaryvoltage of 1247 0 D eltais shown on theinqu iryforitems are 32-52.These bases are on the cu rrentspread sheetwiththe primaryvoltagebeing1247 0 D elta.N eed confirmation thatthe primaryvoltage is 1247 0 D elta.These are the sameas the lastbid ,ithas notchanged .Theyare 1247 0 D eltau nits.System voltage is 1247 0Y /7 200.
P olemou nttransformers:
1. Shellform u nits willnothave interlaced second aries.Shelltype non-interlaced d esigns are notacceptable.
2. N ameplates willbe laseretched anod ized alu minu m.H u ntsville Utilities willnotacceptanod ized A lu minu m.
3. O u r100 KV A and 167 KV A transformers willbe shelltype non-interlaced coild esigns.Shelltype non-interlaced d esigns are notacceptable.(H u ntsville Utilities reserves the righttoevalu ate those u nits separately.)
4. Is thermosetpolyestermaterialacceptable forlow voltage bu shinghou sing(H U has been u singforfive years)?Y es.
P ad mou nttransformers:
1. P entahead boltwillnothave arollpin bu tratheracompression washer.H u ntsville Utilities willrequ ire the rollpin.
2. P entahead boltwillnotbe stainless steelbu trathersilicon bronze.This is acceptable.
3. Stand ard non P C B labeland nameplate willbe provid ed .
H u ntsville Utilities IFB 18 -06 TransformerB idA d d end u m 2
P C B labelis acceptable provid ed itd oes state less than 1P P M in ad d ition to nonP C Bid entification on the nameplate.N ameplate mu stmeetH U specifications.
4. Stand ard testreport(withou texteriord imensions)willbe provid ed .This is acceptable provid edthe d imensions are provid ed on the sales and approvald rawings.
5. Stand ard pallets willbe provid ed .W e willrequ ire 4”x 4”minimu m forthe pallets.
6. W illbe lagbolted to the palletinstead of band ed .This is acceptable.
7 . W e can provid e athree-legged core foryou rD eltau nits instead of a5-legged core.Is a3-leggedC ore acceptable?N o.W e requ ire a5-legged core.
8 . C an we provid e L V porcelain bu shings where appropriate instead of A L L u nits withepox ybu shings?N o.W e willrequ ire epoxy.
9. D u alvoltage d rawings shows amaximu m wid thof 7 7 ”bu tnotsingle voltage,maywe exceed7 7 ”on the D u alvoltage and mu stwe meet7 7 ”on the single voltage? W e willallow u pto 95”wid e on large KV A u nits.
10.D istance between L V bu shings,spec requ ests 6”d esign is 6.5”.6”is aminimu m requ irement6.5”is okprovid ed you d o notexceed overallwid threqu irements.
11.Eachmanu factu rershallfu rnishH u ntsville Utilities withcertified proof,by serialnu mber,thateachtransformerd esign conforms to the shortcircu itrequ irements covered in A N SI/IEEEStand ard C 57 .12.00,Section 7 ,latestrevision,and A N SI/IEEE Stand ard C 57 .12.90,Section 12,latestrevision.C an we provid e certification on u nitd esigns notbyserialnu mber? Thatisacceptable provid ed this information is from an exactd u plicate of the requ ested serialnu mber.
12.C larification:Exteriord imensions willbe provid ed on ou tline d rawings whichaccompanytestresu lts (para10.6.1).D imensions can be provid ed on ou tline d rawings orsimilard ocu ments,bu ttheyshallbe su bmitted withtestreports.
13.W e willprovid e highvoltage bu shingC ooperpart# B W 150F,is thatacceptable? Y es.
14.C an we provid e 12 hole spad e bu shingin lieu of 10 hole? This is acceptable provid ed thespacinghorizontallybetween the holes is notd ecreased .
15.A bove 150 KV A replacementof the low bu shingwillrequ ire openingof the bolton covertoaccess.This is acceptable provid ed access is possible.
16.Is atype A N SItype B nameplate acceptable forallKV A sizes?Y es.
17 .A re two bolts (one 6”from the topand one 6”from the bottom)foraccess to the highvoltagecompartmentacceptable?Y es.
H u ntsville Utilities IFB 18 -06 TransformerB idA d d end u m 2
18 .W e u se a¾”non slotted hole forH V compartmentd oors,is this acceptable? Y es.
19.O n the H V d oorwe u se a1”d iameterstainless flatwasherbetween the d oorand hold ingd evice,is this acceptable? Y es.
20.O n the H V d oorthe washerbetween the springis brass notstainless steel,Is this acceptable?Y es.
21.A re 2 ½”hinges acceptable? N o,they mu stmeetou rspecification of aminimu m of 3”.
22.C an we boltthe transformerto the palletinstead of band ing? N o.
23.H u ntsville Utilities fu singspecifications chartin the three phase pad mou nted transformerspecifications appears to be ou tof d ate.The C ooperchartfortheirreplacementfu ses is attached .
240-98 .pd f
24.W e can onlysu pplyan u ngrou nd ed H V neu tralon 1247 0Y x 24940Y with240 d elta.Shou ld weprovid e aseparate H 0 bu shing(N otgrou nd ed )foorthese particu laritems,orleave the H Vneu tralinternallyisolated and floating? Grou nd ed -W ye primaryis notavailable withthe D eltasecond ary.O n stand ard 240 voltd eltasecond ary this is notacceptable.
25.In reviewingd esigns we bu iltH u ntsville some years ago,Inote the tanks are largerthananticipated .The reason forthe extraheightis thatH u nstville d rawings show the on-off switch6”minimu m above the highestbu shing,on the same line as the B ayonets.Since B ayonets are atthe oillevelline,bu tthe switchmu stbe u nd eroil,6”minimu m on the switchforces atallertankthan 6”minimu m forthe B ayonets.P age 2 d rawingsays the switchmaybe located perthemanu factu rers d iscretion,“within the d imensionalrestrictions”of page 3.W e cou ld red u ce tanksize bylocatingthe switchtoward the centerof the highvoltage,d own in the “V ”of thebu shings.M u stthe switchbe 6”minimu m above the highestbu shing,orwas the d ashed line inthe d rawingforthe B ayonets only? N o.Use manu factu rers d iscretion,makingsu re thattheswitchis operable withallcables in place.
26.This exception applies onlyto those items withd eltaconnected second aries.SpecificallyitemsSeq.54,Seq.57 ,Seq.60,Seq.63,and Seq.66 of B lanketInqu iry13-05.The requ ested bayonetorbayonet/EL SP fu singforthese transformers is notavailable,d u e to the Y -D eltaconnection.The possible recoveryvoltage d u ringfu se operation can reach24940 volts,exceed ingtheclearingcapability (23000 volts)of the requ ested fu singscheme. A n internalcartrid ge fu sewithaP artialRange C u rrentlimitingfu se willbe provid ed on D u alV oltage u nits havingaD eltaSecond ary.The cartrid ge fu se is manu factu red by A B B and the partialrange cu rrent-limitingfu se is manu factu red by H i-Tech.L iteratu re coveringbothfu ses is attached .This is acceptable.
REVISED R. GRIGG _ DATE 12/20/17 ELECTRIC ENGINEERING
112 SPRAGINS STREET HUNTSVILLE, AL 35801
APPROVED ___________ DATE _______
SINGLE-PHASE, SUBMERSIBLE, DUAL VOLTAGE DISTRIBUTION TRANSFORMER SPECIFICATION EED105.15.4 APPROVED K. HENSLEY_____
DATE 12/20/17
PAGE 1 OF 14 GENERAL SPECIFICATIONS FOR UTILITY MATERIAL
HUNTSVILLE UTILITIES ELECTRICAL ENGINEERING
SINGLE-PHASE, SUBMERSIBLE, DISTRIBUTION TRANSFORMER SPECIFICATIONS
PRIMARY VOLTAGE – 7200 X 14400 (DUAL VOLTAGE)
SECONDARY VOLTAGE – AS SPECIFIED BY HUNTSVILLE UTILITIES
1.0 SCOPE
1.1 This specification covers the electrical characteristics and mechanical features of single-phase, 60
Hertz, conventional, mineral oil-immersed, self-cooled, dual voltage, submersiable type,
padmounted, dual voltage, distribution transformers with separable insulated high voltage
connectors.
2.0 STANDARDS
2.1 All characteristics, definitions, terminology, etc., except those that are specifically outlined and/or
modified by this specification, shall be in accordance with ANSI/IEEE Standards C57.12.00,
C57.12.80, and C57.12.90, latest revisions, and ANSI Standards C57.12.23 and C57.12.70, latest
revision.
3.0 SIZES COVERED
3.1 Transformer sizes covered under this specification include 1 kVA through 500 kVA.
4.0 PRIMARY VOLTAGE
4.1 Transformer primary voltage shall be as follows:
Rated Primary Voltage (Dual Voltage)
12470GRDY/7200 x 24940GRDY/14400
5.0 SECONDARY VOLTAGE
5.1 Transformer secondary voltage shall be as specified and/or requested by Huntsville Utilities.
Rated Secondary Voltage (Volts)
REVISED R. GRIGG _ DATE 12/20/17 ELECTRIC ENGINEERING
112 SPRAGINS STREET HUNTSVILLE, AL 35801
APPROVED ___________ DATE _______
SINGLE-PHASE, SUBMERSIBLE, DUAL VOLTAGE DISTRIBUTION TRANSFORMER SPECIFICATION EED105.15.4 APPROVED K. HENSLEY_____
DATE 12/20/17
PAGE 2 OF 14 GENERAL SPECIFICATIONS FOR UTILITY MATERIAL
1. 240/120
2. 480/240
3. 277
6.0 INSULATION LEVEL
6.1 The high voltage insulation shall be as follows:
Rated High Voltage (Volts) BIL (kV) Insulation Class (kV)
12470GRDY/7200 x 24940GRDY/14400 125 18
6.2 The low voltage insulation shall have a BIL rating of 30 kV and be of the 1.2 kV insulation class.
7.0 TEMPERATURE RISE LIMITS
7.1 Temperature rise and loading conditions shall conform to ANSI/IEEE Standard C57.12.90,
Section 11, latest revision, and ANSI/IEEE Standard C57.12.00, Section 5.11, latest revision.
8.0 REFERENCE TEMPERATURE
8.1 The reference temperature to which losses, impedance, regulation, and efficiency are corrected
shall be 85C.
9.0 TESTING
9.1 Each transformer shipped to Huntsville Utilities shall pass each and every test specified herein.
9.2 Routine tests shall be conducted on each transformer, and, except as specified in ANSI Standard
C57.12.23, Section 5.2, latest revision, all testing procedures shall follow and/or comply with
ANSI/IEEE Standard C57.12.00 and ANSI/IEEE Standard C57.12.90, latest revisions.
9.3 Each transformer manufacturer shall perform a production line full-wave voltage impulse test of
each unit prior to shipment. Each respective transformer manufacturer shall furnish Huntsville
Utilities with a detailed description of the procedure(s) and test method(s) used during the
execution of each production line impulse test.
9.4 Each manufacturer shall furnish Huntsville Utilities with certified proof, by serial number, that
each transformer design conforms to the short circuit requirements covered in ANSI/IEEE
REVISED R. GRIGG _ DATE 12/20/17 ELECTRIC ENGINEERING
112 SPRAGINS STREET HUNTSVILLE, AL 35801
APPROVED ___________ DATE _______
SINGLE-PHASE, SUBMERSIBLE, DUAL VOLTAGE DISTRIBUTION TRANSFORMER SPECIFICATION EED105.15.4 APPROVED K. HENSLEY_____
DATE 12/20/17
PAGE 3 OF 14 GENERAL SPECIFICATIONS FOR UTILITY MATERIAL
Standard C57.12.00, latest revision, Section 7, latest revision, and ANSI/IEEE Standard
C57.12.90, Section 12, latest revision.
9.5 Each manufacturer shall furnish Huntsville Utilities with a certified test report, by serial number,
for each transformer. Each certified test report shall include the following information:
A. Percent impedance; (85° C)
B. Load loss (quoted and actual);
C. No load loss (quoted and actual);
D. Total loss (quoted and actual);
E. Percent excitation current; (@100% Voltage)
F. High and low voltage ratings;
G. Serial number of unit;
H. kVA size;
I. Exterior dimensions;
J. Huntsville Utilities purchase order number.
9.6 Each manufacturer shall ship to Huntsville Utilities one (1) copy of each certified test report for
each transformer. Receipt of one (1) copy of each certified test report for each transformer is
a requirement for payment. Certified test reports shall be shipped within thirty (30) days of
transformer shipment to the following address:
Huntsville Utilities
Purchasing Department
P.O. Box 2048
Huntsville, AL 35804
10.0 CONSTRUCTION AND DESIGN
10.1 Each transformer shall be constructed and/or designed to meet or exceed construction standards
set forth by ANSI Standard C57.12.23, Section 6, latest revision.
REVISED R. GRIGG _ DATE 12/20/17 ELECTRIC ENGINEERING
112 SPRAGINS STREET HUNTSVILLE, AL 35801
APPROVED ___________ DATE _______
SINGLE-PHASE, SUBMERSIBLE, DUAL VOLTAGE DISTRIBUTION TRANSFORMER SPECIFICATION EED105.15.4 APPROVED K. HENSLEY_____
DATE 12/20/17
PAGE 4 OF 14 GENERAL SPECIFICATIONS FOR UTILITY MATERIAL
10.2 Dual primary voltage transformers shall be designed such that under normal operating conditions,
no electrical or mechanical damage will occur when the dual voltage switch is set in any possible
setting.
10.3 Each transformer shall be of the sealed tank design suitable for continuous operation while
completely submerged.
10.4 Transformer shall be designed to remain sealed within temperature range limits as outlined in
ANSI Standard C57.12.23, Section 6.4.1, latest revision.
10.5 Switch handles, separable connectors, replaceable fuses, and other accessories designed for
opertation after the transformer is in place shall be located on the transformer so that they can be
operated from above with hot-line tools.
10.6 Overall transformer dimensions shall conform to ANSI Standard C57.12.23, Section 6.1.1, latest
revision.
10.7 Transformer tank, cover, and exterior appurtenances shall be constructed of stainless steel.
10.8 All insulating paper uses as layer insulation in transforme coil assembly shall be bonded type,
coated on both sides with a thermosetting adhesive and properly cured prior to impregnating with
oil, or the coils shall be wound with primary conductor containing a thermosetting adhesive that
when properly cured will form an effective bond, both turn to turn and layer to layer.
11.0 TANK FINISH
11.1 Each transformer shall have a coal-tar epoxy finish. Manufacturer’s standard overfinish of paint
will be acceptable on top of coal-tar epoxy. If paint is used, paint finish shall be
weather/oil/corrosion-resistant of such quality that it meets or exceeds Proposed EEI Finishing
Requirements, latest revision.
11.2 Tank coats on transformers rated 100 kVA and below shall be a finish capable of withstanding a
direct blow of 160 inch-pounds per ASTM D-2794-69.
12.0 BUSHINGS AND TERMINALS
12.1 The electrical characteristics of the transformer bushings and terminals shall be as follows:
60-Hertz
Insulation Class BIL Dry One-Minute Withstand
25 kV 125 kV 40 kV
REVISED R. GRIGG _ DATE 12/20/17 ELECTRIC ENGINEERING
112 SPRAGINS STREET HUNTSVILLE, AL 35801
APPROVED ___________ DATE _______
SINGLE-PHASE, SUBMERSIBLE, DUAL VOLTAGE DISTRIBUTION TRANSFORMER SPECIFICATION EED105.15.4 APPROVED K. HENSLEY_____
DATE 12/20/17
PAGE 5 OF 14 GENERAL SPECIFICATIONS FOR UTILITY MATERIAL
1.2 kV 30 kV 10 kV
12.2 Electrical characteristics, number, location, and physical arrangement of high voltage bushing
wells and connectors shall be as specified in ANSI Standard C57.12.20, Section 6.2, latest revision.
12.3 Two (2), high voltage, externally clamped, T&B (Blackburn), Central Moloney, T&B
(Elastimold), or Cooper (RTE) bushing wells, which will accept T&B (Blackburn), T&B
(Elastimold), or Cooper (RTE) load-break bushing inserts, shall be provided to permit the
operation of the transformer in a looped primary cable system. The bushing wells shall be marked
with the name of the manufacturer externally visible after installation. Copreme or Nitrile
gasketing material shall be provided and limiters shall be installed to prevent excessive
compression of the gaskets.
12.4 All high voltage leads shall be insulated and arranged to ensure that lead to ground contact is not
possible. Bushing wells shall be externally removable, and high voltage leads shall be of sufficient
length to permit field replacement of the bushing wells without opening the tank.
12.5 Electrical characteristics, number, location, and physical arrangement of low voltage terminal
leads shall be as specified in ANSI Standard C57.12.23, Section 6.2, latest revision.
12.6 Low-Voltage termination for units below 167 kVA shall consist of three (3) leads of underground,
insulated, stranded copper conductor six feet (6’) in length and sized per Table #1.
12.7 All low voltage leads shall be insulated and arranged to ensure that lead to ground contact is not
possible. Bushing wells shall be externally removable, and low voltage leads shall be of sufficient
length to permit field replacement of the bushing wells without opening the tank.
12.8 Internal secondary leads shall be identified with appropriate markings permanently embossed in
the leads that correspond with lead markings on the nameplate.
12.9 Terminal markings and designations shall be as specified by ANSI Standard C57.12.70, latest
revision.
12.10 All high voltage bushing wells and connectors and low voltage terminals shall be clearly marked
on the transformer tanks with weather/oil/corrosion-resistant, yellow paint or Huntsville Utilities
approved transformer markings. Gummed and/or adhesive labels and/or signs will NOT be
acceptable.
12.11 Terminal designations shall be readable with all cables in place.
REVISED R. GRIGG _ DATE 12/20/17 ELECTRIC ENGINEERING
112 SPRAGINS STREET HUNTSVILLE, AL 35801
APPROVED ___________ DATE _______
SINGLE-PHASE, SUBMERSIBLE, DUAL VOLTAGE DISTRIBUTION TRANSFORMER SPECIFICATION EED105.15.4 APPROVED K. HENSLEY_____
DATE 12/20/17
PAGE 6 OF 14 GENERAL SPECIFICATIONS FOR UTILITY MATERIAL
12.12 An accessory mounting parking bracket for use with the test/grounding bushing and parking
bushing for load-break terminators shall be supplied beside each high-voltage bushing well as
specified by ANSI Standard C57.12.23 Section 6.2, latest revision.
REVISED R. GRIGG _ DATE 12/20/17 ELECTRIC ENGINEERING
112 SPRAGINS STREET HUNTSVILLE, AL 35801
APPROVED ___________ DATE _______
SINGLE-PHASE, SUBMERSIBLE, DUAL VOLTAGE DISTRIBUTION TRANSFORMER SPECIFICATION EED105.15.4 APPROVED K. HENSLEY_____
DATE 12/20/17
PAGE 7 OF 14 GENERAL SPECIFICATIONS FOR UTILITY MATERIAL
12.13 In order to permit operation of the transformer in a looped primary cable system, transformer
components shall have minimum current-carrying capabilities of two hundred amperes (200A)
(continuous) and ten thousand amperes (10,000A) RMS symmetrical for 0.17 seconds (short-time
current rating) for transformers with or without high voltage switching.
13.0 ACCESSORIES
13.1 Each transformer shall be equipped with an externally operated, two (2) position, dual voltage
(7200 x 14400 Volts) switch. The dual voltage switch handle shall be brought out through the top
of the transformer tank for external operation. The dual voltage switch shall be clearly designated
with Huntsville Utilities approved transformer markings. Switch positions shall be indicated 7200
Volts (7.2 kV) x 14400 Volts (14.4 kV). In addition, the dual voltage switch shall: (1) clearly
indicate its purpose and switch positions; (2) be easily readable and operable with all conductors
in place; (3) be clearly marked for de-energized operation only. Transformers shall be shipped
with the dual voltage switch in the 7200 Volt position.
13.2 Each transformer shall be equipped with lifting provisions permanently attached and arranged on
the transformer tank to provide a distributed balanced lift in a vertical direction for the completely
assembled transformer as specified in ANSI Standard C57.12.23, Section 6.1.5, latest revision.
13.3 Base bars or other suitable means shall be furnished to protect the bottom of the tank while in
transit and during installation.
13.4 Each transformer shall be supplied with a durable, metal, instruction nameplate located as
specified by ANSI Standard C57.12.23, Section 6.3,latest revision. The nameplate shall be made
of stainless steel or other approved, non-corrosive metal and permanently marked with essential
operating data. The nameplate shall contain information for Nameplate A, as specified in
ANSI/IEEE Standard C57.12.00, Section 5.12, latest revision. The following information shall be
included on the transformer nameplate: (1) the BIL rating of the transformer; (2) decoded date the
transformer is manufactured (Example: MFR. DATE 10/17); (3) notation of the current limiting
and Bay-O-Net fuses in the circuit diagram. The nameplate shall be attached to the transformer
with weather/corrosion-resistant fasteners. The nameplate shall be readable with all conductors
in place.
13.5 Each transformer shall be provided with a Qualitrol, self-actuating, pressure relief device. The
pressure relief device shall automatically vent when the pressure reaches 102 PSIG and reseal
when the pressure falls to 6 PSIG. Exposed parts shall be made of weather/oil/corrosion-resistant
materials. Approved pressure relief devices must meet or exceed ANSI Standard C57.12.23,
Section 6.5, latest revision.
13.6 All external markings (kVA markings, switch indicators, bushing markings, etc.) shall be either
permanently painted on the unit using weather/oil/corrosion-resistant paint or shall be permanently
REVISED R. GRIGG _ DATE 12/20/17 ELECTRIC ENGINEERING
112 SPRAGINS STREET HUNTSVILLE, AL 35801
APPROVED ___________ DATE _______
SINGLE-PHASE, SUBMERSIBLE, DUAL VOLTAGE DISTRIBUTION TRANSFORMER SPECIFICATION EED105.15.4 APPROVED K. HENSLEY_____
DATE 12/20/17
PAGE 8 OF 14 GENERAL SPECIFICATIONS FOR UTILITY MATERIAL
marked on stainless steel plates riveted, welded or bolted to the unit. Any exceptions to this
specification requires prior approval from Huntsville Utilities.
13.7 No gummed labels or signs shall be attached to the exterior surface of the transformer, except:
A. Those cited in Section 15.2.
B. A label containing the manufacturer’s serial number and Huntsville Utilities’ commodity
number and purchase order number shall be affixed on the rear surface of the transformer.
13.8 No warning labels or signs shall be attached to the exterior surface of the transformer.
14.0 TANKS
14.1 Each transformer tank shall be designed in accordance with ANSI Standard C57.12.23, latest
revision.
14.2 Each transformer tank shall be of sufficient strength to withstand a pressure of seven (7) PSIG
without permanent distortion of the tank as outlined in ANSI Standard C57.12.23, Section 6.5.1,
latest revision.
14.3 Each transformer manufacturer shall furnish each transformer with tank grounding provisions.
Tank grounding provisions shall be constructed per ANSI Standard C57.12.23, Section 6.5.4,
latest revision. Tank grounding provisions shall be capped before the unit is painted.
14.4 Tank covers shall be domed or sloped to prohibit moisture accumulation.
15.0 INSULATING OIL
15.1 Each transformer shall be filled with mineral insulating oil and shall be certified to contain less
than one part per million (1ppm) Polychlorinated Biphenyls (PCB's) as measured on a dry weight
basis. A notice to this affect shall be included on the transformer nameplate.
EXAMPLE:
FILLED WITH OIL CONTAINING LESS THAN 1 PPM PCB's
or
CONTAINS LESS THAN 1 PPM PCB's 15.2 A separate, standard “Non-PCB” label, blue background with white lettering with the following
legend: “Non-PCB Mineral Oil – when manufactured contained less than 1 PPM PCB” shall be attached to the top of all submersible transformers.
REVISED R. GRIGG _ DATE 12/20/17 ELECTRIC ENGINEERING
112 SPRAGINS STREET HUNTSVILLE, AL 35801
APPROVED ___________ DATE _______
SINGLE-PHASE, SUBMERSIBLE, DUAL VOLTAGE DISTRIBUTION TRANSFORMER SPECIFICATION EED105.15.4 APPROVED K. HENSLEY_____
DATE 12/20/17
PAGE 9 OF 14 GENERAL SPECIFICATIONS FOR UTILITY MATERIAL
16.0 FUSING
16.1 Each transformer shall be furnished with an approved, oil-immersed, Cooper (RTE) or ABB
(Westinghouse) Bay-O-Net draw-out fuse holder and an approved, current sensing, Cooper (RTE)
Bay-O-Net fuse element.
16.2 A series connected, partial-range, oil-immersed, Chance Type "TL", Hi-Tech Type "OS", or RTE
Type "ELSP" current limiting fuse, suitably sized for both voltages (see table #1), shall be installed
on the source side of each Bay-O-Net fuse.
16.3 The current limiting fuse shall be mounted in accordance with the fuse manufacturer's
recommendation in the immediate vicinity of the loop buss and ahead of the Bay-O-Net fuse
feeding the primary winding. The current limiting fuse shall be rigidly mounted to eliminate
shifting of the fuse and/or the possibility of fuse to ground contact. The dislodging of a current
limiting fuse will result in the immediate removal of the respective manufacturer from Huntsville
Utilities' list of approved manufacturers.
16.4 The Bay-O-Net fuse shall be mounted on top of the transformer and positioned so that the fuse
may be easily removed and installed by a person using a hot stick from above.
16.5 The Bay-O-Net fuse holders shall be marked so that the name of the manufacturer is externally
visible after installation.
16.6 Transformers shall be shipped with the 7200 Volt Bay-O-Net fuse installed.
16.7 Bay-O-Net fuses and current limiting fuses shall be sized per table #1.
17.0 SHIPPING
17.1 Each transformer shall be placed on a solid wood pallet for shipment. Each transformer shall be
secured to the pallet with two steel bands attached to the transformer lifting provisions in a manner
that prevents damage to the transformer paint finish. Transformers shall not be stacked.
17.2 A tag indicating Huntsville Utilities' commodity number and purchase order number shall be
attached to the transformer inside the terminating compartment.
18.0 LOSS EVALUATIONS
18.1 The following performance information is to be furnished by each transformer manufacturer with
the quotation.
REVISED R. GRIGG _ DATE 12/20/17 ELECTRIC ENGINEERING
112 SPRAGINS STREET HUNTSVILLE, AL 35801
APPROVED ___________ DATE _______
SINGLE-PHASE, SUBMERSIBLE, DUAL VOLTAGE DISTRIBUTION TRANSFORMER SPECIFICATION EED105.15.4 APPROVED K. HENSLEY_____
DATE 12/20/17
PAGE 10 OF 14 GENERAL SPECIFICATIONS FOR UTILITY MATERIAL
1. No load losses in watts at normal frequency and voltage.
2. Total full load losses in watts at normal frequency and voltage.
Loss evaluation is an integral factor in the final selection process. The evaluation of losses will be
based on the total cost of ownership for 30 years based on the following formula:
Cost of Ownership = $1.791 x Purchase Price
Plus $7.4206 x No load loss in watts
Plus $3.3393 x Load loss in watts
Where the load losses are computed as Total loss - No load
loss
19.0 TOLERANCES FOR LOSSES
19.1 The quoted losses shall be guaranteed by the manufacturer as specified in ANSI/IEEE C57.12.00,
Section 9.3, latest revision (IE each unit received, shall be evaluated for load losses on an
individual basis {rather than an average basis} as defined in paragraphs 20.0 through 23.2).
20.0 LOSS VERIFICATION
20.1 Each manufacturer shall furnish Huntsville Utilities with certified loss test reports, by serial
number, for each unit. Receipt of the certified loss test reports by Huntsville Utilities shall be
a requirement for payment. Each certified test report shall include loss data as specifically
required for quotation as well as size and configuration of each transformer.
20.2 Each certified test report will be reviewed by Huntsville Utilities to ensure that each transformer
conforms to ANSI/IEEE Standard C57.12.00, (latest revision).
20.3 Each shipment of distribution transformers received by Huntsville Utilities will be routinely and/or
randomly sampled and loss tested. Huntsville Utilities personnel will compare data obtained
through this loss testing procedure to the data provided by the manufacturer in the certified test
reports. The manufacturer's certified loss data must be within 2% of the data obtained by
Huntsville Utilities testing.
20.4 If the loss data obtained by Huntsville Utilities testing is not within 2% of the manufacturer's
certified loss data, Huntsville Utilities will choose one or more of the following corrective actions:
A. Conduct loss testing on the entire lot of transformers received by Huntsville Utilities with the
loss testing results being used in place of the certified loss data reported by the manufacturer.
REVISED R. GRIGG _ DATE 12/20/17 ELECTRIC ENGINEERING
112 SPRAGINS STREET HUNTSVILLE, AL 35801
APPROVED ___________ DATE _______
SINGLE-PHASE, SUBMERSIBLE, DUAL VOLTAGE DISTRIBUTION TRANSFORMER SPECIFICATION EED105.15.4 APPROVED K. HENSLEY_____
DATE 12/20/17
PAGE 11 OF 14 GENERAL SPECIFICATIONS FOR UTILITY MATERIAL
The cost of the loss testing shall be credited to Huntsville Utilities by the respective
manufacturer.
B. Reject the entire lot of transformers and return the transformers to the respective manufacturer
at the manufacturer's expense.
C. Return a random sampling of the lot of transformers to the respective manufacturer for
verification of the loss test data by the manufacturer.
D. Subject a random sampling of the lot of transformers to testing conducted by a mutually
agreed upon third party test laboratory.
If actions taken under Items C. and D. indicate that the manufacturer's certified loss data is
inaccurate, the respective manufacturer will bear the expense of the above action(s).
20.5 Any manufacturer whose certified test reports are found to be in error shall be subject to probation,
suspension, and/or deletion as an approved supplier. Such suspension or deletion shall not
necessarily be limited to a particular item or class of items.
21.0 LOSS ADJUSTMENT PROCEDURES
21.1 Transformer losses shall not exceed tolerances specified in ANSI/IEEE Standard C57.12.00,
Section 9.3 - Tolerances for Losses (latest revision). Each transformer that fails to conform to this
standard shall be returned to the manufacturer, freight collect, for replacement. Alternately,
Huntsville Utilities may require credit from the manufacturer equal to the present value of the
added cost of ownership for a 30-year period but not to exceed the original purchase cost of the
transformer. The credit required shall be based on the difference of the actual losses and quoted
losses using the evaluation formula costs.
Example:
Evaluation Definitions: Quoted Values: Actual Values:
PPF Purchase Price Factor = 1.791 Purchase Price = $10.00 Purchase Price = $10.00
NLF No Load Loss Factor = 7.4206 No Load Losses = 1.0 No Load Losses = 1.2
LLF Load Loss Factor = 3.3393 Load Losses = 2 Load Losses = 2.1
Quoted Values Actual Values
REVISED R. GRIGG _ DATE 12/20/17 ELECTRIC ENGINEERING
112 SPRAGINS STREET HUNTSVILLE, AL 35801
APPROVED ___________ DATE _______
SINGLE-PHASE, SUBMERSIBLE, DUAL VOLTAGE DISTRIBUTION TRANSFORMER SPECIFICATION EED105.15.4 APPROVED K. HENSLEY_____
DATE 12/20/17
PAGE 12 OF 14 GENERAL SPECIFICATIONS FOR UTILITY MATERIAL
Purchase Price times PPF $10.00 * 1.791 = 17.91 $10.00 * 1.791 = 17.91
Plus + +
No load losses times NLF 1.0 * 7.4206 = 7.4206 1.2 * 7.4206 = 8.90472
Plus + +
Load Losses times LLF 2.0 * 3.3393 = 6.6786 2.1 * 3.3393 = 7.01253
Equals Evaluation value = 32.0092 = 33.82725
Quoted evaluation 32.0092
Minus -
Actual evaluation 33.82725
Equals Evaluated Difference 1.81805
Evaluated Difference (1.81805)
Divided by purchase price factor 1.791
Equals Purchase Price Adjustment (1.0151)
Check: re-evaluate units with adjustment to purchase price:
Quoted Purchase Price $10.00
Plus Purchase Price Adjustment ( 1.0151)
Equals Actual Purchase Price $ 8.9849
Actual Purchase Price times PPF $ 8.9849 * 1.791 = 16.0919559
Plus +
No load losses times NLF 1.2 * 7.4206 = 8.90472
Plus +
Load Losses times LLF 2.1 * 3.3393 = 7.01253
Equals Evaluation value = 32.00092
This equals the quoted evaluated life cost.
Thus the computed adjustment is accurate.
The required credit would be the 1.0151 or 1.02 if rounded to cents (since .0051 is greater than .005).
If the adjustment above had been positive, the actual losses would have been less than quoted and no
credit would have been due from the manufacturer.
We would not issue a credit to the manufacturer for beating his loss quotation.
REVISED R. GRIGG _ DATE 12/20/17 ELECTRIC ENGINEERING
112 SPRAGINS STREET HUNTSVILLE, AL 35801
APPROVED ___________ DATE _______
SINGLE-PHASE, SUBMERSIBLE, DUAL VOLTAGE DISTRIBUTION TRANSFORMER SPECIFICATION EED105.15.4 APPROVED K. HENSLEY_____
DATE 12/20/17
PAGE 13 OF 14 GENERAL SPECIFICATIONS FOR UTILITY MATERIAL
Per ANSI C-57.12.00.9.3, tolerances for losses are as follows:
Number of No-load Load
Units on Basis of Losses Losses
One Order Determination (%) (%)
1 1 10 6
2 or more Each unit 10 6
2 or more Average of 0 0
all units
Therefore, each unit must be within 10% on no load losses and within 6% on load losses. If more than
one identical unit is shipped as one order in a single shipment, the average of all units must meet quoted
losses with no tolerance.
21.2 Any manufacturer who supplies Huntsville Utilities with transformers that repeatedly fail to meet
quoted losses shall be subject to probation, suspension, and/or complete deletion as an approved
supplier.
22.0 EXCEPTIONS AND DEVIATIONS
22.1 Manufacturers quoting transformers to this specification shall indicate any areas where changes
to this design and/or specification are required by their design standards. Any recommended
changes to this design and/or specification offered by the manufacturer shall be accompanied by
sufficient information to permit full evaluation of the desired changes. Any change to this design
and/or specification requires prior approval from Huntsville Utilities Electrical Engineering.
Detailed approval drawings, design criteria, test data, and prototype samples shall be submitted
with design or specification change requests.
22.2 Huntsville Utilities will routinely and/or randomly inspect and/or test each shipment of
transformers to ensure that each transformer received conforms to this specification and/or
any agreed upon deviations.
22.3 Bids will be awarded to manufacturers based on the manufacturer's stated compliance with this
specification in its entirety. In the event that a bid is awarded to a manufacturer, and said
manufacturer's product is discovered not to be in compliance with this specification (and/or any
agreed upon deviations) in any manner, any/all of the following actions will be required by
Huntsville Utilities:
1. Any transformers received that do not comply with this specification in its entirety will be
rejected and returned to the manufacturer at the manufacturer's expense.
REVISED R. GRIGG _ DATE 12/20/17 ELECTRIC ENGINEERING
112 SPRAGINS STREET HUNTSVILLE, AL 35801
APPROVED ___________ DATE _______
SINGLE-PHASE, SUBMERSIBLE, DUAL VOLTAGE DISTRIBUTION TRANSFORMER SPECIFICATION EED105.15.4 APPROVED K. HENSLEY_____
DATE 12/20/17
PAGE 14 OF 14 GENERAL SPECIFICATIONS FOR UTILITY MATERIAL
2. The respective manufacturer will be required to provide Huntsville Utilities with the number
of units initially quoted (at the initial quoted price and loss values) which do comply with this
specification in its entirety. Provision of the initial number of units quoted by the respective
manufacturer is mandatory even if said manufacturer is required to supply units manufactured
by another approved source. Units supplied by another approved source shall be delivered in
the time specified by the manufacturer winning the bid.
3. Failure to comply with this specification (and/or any agreed upon deviations) in its entirety
may result in the manufacturer's immediate suspension or removal from Huntsville Utilities'
list of approved manufacturers. Such suspension or deletion shall not necessarily be limited
to a particular item or class of items.
REVISED R. GRIGG _ DATE 12/20/17 ELECTRIC ENGINEERING
112 SPRAGINS STREET HUNTSVILLE, AL 35801
APPROVED ___________ DATE _______
SINGLE-PHASE, SUBMERSIBLE, DUAL VOLTAGE DISTRIBUTION TRANSFORMER SPECIFICATION EED105.15.4 APPROVED K. HENSLEY_____
DATE 12/20/17
PAGE 15 OF 14 GENERAL SPECIFICATIONS FOR UTILITY MATERIAL
TABLE #1
FUSING SPECIFICATIONS CHART FOR
SINGLE-PHASE, SUBMERSIBLE, DISTRIBUTION TRANSFORMERS
PRIMARY VOLTAGE – 7200 x 14400 VOLTS (DUAL VOLTAGE)
SECONDARY VOLTAGE – AS SPECIFIED BY HUNTSVILLE UTILITIES
kVA
SIZE
RTE
7200Volt
“Bay-O-Net”
Current Sensing
Fuse Element
RTE
14400 Volt
“Bay-O-Net”
Current Sensing
Fuse Element
PARTIAL RANGE
CURRENT LIMITING
FUSE
CHANCE
TYPE “TL”
HI-TECH
TYPE “OS”
RTE
TYPE “ELSP”
CONDUCTOR
SIZE 25
4000353C06
4000353C04
C705-0797
HTDS242035
3544030M61M
2/0
37.5
4000353C06
4000353C04
C705-0797
HTDS242035
3544040M61M
2/0
50
4000353C08
4000353C06
C705-0798
HTDS242035
3544050M61M
4/0
75
4000353C10
4000353C08
-----------
HTDS242065
354480M71M
350 MCM
100
4000353C10
4000353C08
-----------
HTDS242065
354480M71M
500 MCM
167
4000353C12
4000353C10
-----------
HTDS242100
3544125M71M
500 MCM
(2 PER LEG)
REVISED R. GRIGG _ DATE 12/20/17 ELECTRIC ENGINEERING
112 SPRAGINS STREET HUNTSVILLE, AL 35801
APPROVED ___________ DATE _______
SINGLE-PHASE, OVERHEAD, DUAL VOLTAGE DISTRIBUTION TRANSFORMER SPECIFICATION EED105.39.10 APPROVED K. HENSLEY____
DATE 12/20/17
PAGE 1 OF 11 GENERAL SPECIFICATIONS FOR UTILITY MATERIAL
HUNTSVILLE UTILITIES ELECTRICAL ENGINEERING
SINGLE-PHASE, OVERHEAD, DUAL VOLTAGE, DISTRIBUTION TRANSFORMER SPECIFICATIONS
PRIMARY VOLTAGE – 7200 X 14400 (DUAL VOLTAGE)
SECONDARY VOLTAGE – AS SPECIFIED BY HUNTSVILLE UTILITIES
1.0 SCOPE
1.1 This specification covers the electrical characteristics and mechanical features of single-phase, 60
Hertz, conventional, mineral oil-immersed, self-cooled, dual voltage, overhead type, distribution
transformers.
2.0 STANDARDS
2.1 All characteristics, definitions, terminology, etc., except those that are specifically outlined and/or
modified by these specifications, shall be in accordance with ANSI / (IEEE) Standards C57.12.00,
C57.12.80, and C57.12.90, latest revisions, and ANSI Standards C57.12.20 and C57.12.70, latest
revisions.
3.0 SIZES COVERED
3.1 Transformer sizes covered under this specification include 1 kVA through 500 kVA.
4.0 PRIMARY VOLTAGE
4.1 Transformer primary voltage shall be as specified and/or requested by Huntsville Utilities.
Rated Primary Voltage (Dual Voltage)
1) 7200/12470Y x 14400/24940Y
5.0 SECONDARY VOLTAGE
5.1 Transformer secondary voltage shall be as specified and/or requested by Huntsville Utilities.
Rated Secondary Voltage
1) 120/240
REVISED R. GRIGG _ DATE 12/20/17 ELECTRIC ENGINEERING
112 SPRAGINS STREET HUNTSVILLE, AL 35801
APPROVED ___________ DATE _______
SINGLE-PHASE, OVERHEAD, DUAL VOLTAGE DISTRIBUTION TRANSFORMER SPECIFICATION EED105.39.10 APPROVED K. HENSLEY____
DATE 12/20/17
PAGE 2 OF 11 GENERAL SPECIFICATIONS FOR UTILITY MATERIAL
2) 240/480
3) 277
6.0 INSULATION LEVEL
6.1 The high voltage insulation shall be as follows:
Rated High Voltage (Volts) BIL (kV) Insulation Class (kV)
7200 / 12470 Y 125 25
x
14400 / 24940 Y
6.2 The low voltage insulation shall have a BIL rating of 30 kV and be of the 1.2 kV insulation class.
7.0 TEMPERATURE RISE LIMITS
7.1 Temperature rise and loading conditions shall conform to ANSI/IEEE Standard C57.12.90, Section
11, latest revision, and ANSI/IEEE Standard C57.12.00, Section 5.11, latest revision.
8.0 REFERENCE TEMPERATURE
8.1 The reference temperature to which losses, impedance, regulation, and efficiency are corrected shall
be 85C.
9.0 TESTING
9.1 Each transformer shipped to Huntsville Utilities shall pass each and every test specified herein.
9.2 Routine tests shall be conducted on each transformer, and, except as specified in ANSI Standard
C57.12.20, Section 5.2, latest revision, all testing procedures shall follow and/or comply with
ANSI/IEEE Standard C57.12.00 and ANSI/IEEE Standard C57.12.90, latest revisions.
9.3 Each transformer manufacturer shall perform a production line full-wave voltage impulse test of
each unit prior to shipment. Each respective transformer manufacturer shall furnish Huntsville
Utilities with a detailed description of the procedure(s) and test method(s) used during the execution
of each production line impulse test.
9.4 Each manufacturer shall furnish Huntsville Utilities with certified proof, by serial number, that each
transformer design conforms to the short circuit requirements covered in ANSI/IEEE Standard
C57.12.00, Section 7, latest revision, and ANSI/IEEE Standard C57.12.90, Section 12, latest
revision.
9.5 Each manufacturer shall furnish Huntsville Utilities with a certified test report, by serial number, for
REVISED R. GRIGG _ DATE 12/20/17 ELECTRIC ENGINEERING
112 SPRAGINS STREET HUNTSVILLE, AL 35801
APPROVED ___________ DATE _______
SINGLE-PHASE, OVERHEAD, DUAL VOLTAGE DISTRIBUTION TRANSFORMER SPECIFICATION EED105.39.10 APPROVED K. HENSLEY____
DATE 12/20/17
PAGE 3 OF 11 GENERAL SPECIFICATIONS FOR UTILITY MATERIAL
each transformer. Each certified test report shall include the following information:
A. Percent impedance (85C)
B. Load loss (quoted and actual)
C. No load loss (quoted and actual)
D. Total loss (quoted and actual)
E. Percent excitation current (@ 100% Voltage)
F. High and low voltage ratings
G. Serial number of unit
H. kVA size
I. Exterior dimensions
I. Huntsville Utilities purchase order number
9.6 Each manufacturer shall ship to Huntsville Utilities one (1) copy of each certified test report for each
transformer. Receipt of one (1) copy of each certified test report for each transformer is a
requirement for payment. Certified test reports shall be shipped within thirty (30) days of
transformer shipment to the following address:
Huntsville Utilities
Purchasing Department
P. O. Box 2048
Huntsville, AL 35804
10.0 CONSTRUCTION AND DESIGN
10.1 Each transformer shall be constructed and/or designed to meet or exceed construction standards set
forth by ANSI Standard C57.12.20, latest revision.
10.2 Dual primary voltage transformers shall be designed such that under normal operating conditions,
no electrical or mechanical damage will occur when the dual voltage switch is set in any possible
setting.
REVISED R. GRIGG _ DATE 12/20/17 ELECTRIC ENGINEERING
112 SPRAGINS STREET HUNTSVILLE, AL 35801
APPROVED ___________ DATE _______
SINGLE-PHASE, OVERHEAD, DUAL VOLTAGE DISTRIBUTION TRANSFORMER SPECIFICATION EED105.39.10 APPROVED K. HENSLEY____
DATE 12/20/17
PAGE 4 OF 11 GENERAL SPECIFICATIONS FOR UTILITY MATERIAL
10.3 All insulating paper used as layer insulation in transformer coil assembly shall be bonded type,
coated on both sides with a thermosetting adhesive and properly cured prior to impregnating with
oil, or the coils shall be wound with primary conductor containing a thermosetting adhesive that
when properly cured will form an effective bond, both turn to turn and layer to layer.
10.4 Transformer core-coil shall be of either shell or core type interlaced design. Shell type non-
interlaced designs are not acceptable.
11.0 TANK FINISH
11.1 Each transformer shall have a light gray (Light Gray No. 70, Munsell Notation 5BG 7.0/0.4 or
equivalent), weather/corrosion-resistant paint finish. Paint shall be of such quality that it meets or
exceeds Proposed EEI Finishing Requirements, latest revision.
11.2 Transformers one hundred (100) kVA and below shall have an insulated coating on the tank cover
capable of withstanding 12 kV at a 2000 volts/second rate of rise or 15 kV at 500 volts/second rate
of rise tested per ASTM D149 using 1/4" diameter electrodes. The results of design tests to confirm
this capability shall be submitted for approval.
11.3 Tank coats on transformers rated 100 kVA and below shall be a finish capable of withstanding a
direct blow of 160 inch-pounds per ASTM D-2794-69.
11.4 For transformers rated above 100 kVA, the minimum acceptable coating shall be a thermosetting
powder 2.5-3.5 MILS thick.
12.0 BUSHINGS AND TERMINALS
12.1 Each transformer shall be provided with cover-mounted, high voltage, wet-process, porcelain
bushing(s) with eyebolt terminals.
12.2 High voltage bushings shall be gasketed and internally clamped to provide a moisture proof and/or
oil proof seal.
12.3 Color of high voltage bushing(s) shall match Light Gray No. 70, Munsell Notation 5BG 7.0/0.4.12.4
Electrical characteristics, number, location, and physical arrangement of high voltage bushing(s)
shall be as specified in ANSI Standard C57.12.20, Section 6, latest revision.
12.4 Each transformer shall be furnished with low voltage, two-piece, porcelain or glass polyester
bushings with terminals per ANSI Standard C57.12.20, Section 6.1.2, latest revisions.
12.5 Low voltage bushings shall be securely keyed and sealed to prohibit moisture and/or oil migration.
12.6 Electrical characteristics, number, location, and physical arrangement of low voltage terminals shall
be as specified in ANSI Standard C57.12.20, Section 6, latest revision.
REVISED R. GRIGG _ DATE 12/20/17 ELECTRIC ENGINEERING
112 SPRAGINS STREET HUNTSVILLE, AL 35801
APPROVED ___________ DATE _______
SINGLE-PHASE, OVERHEAD, DUAL VOLTAGE DISTRIBUTION TRANSFORMER SPECIFICATION EED105.39.10 APPROVED K. HENSLEY____
DATE 12/20/17
PAGE 5 OF 11 GENERAL SPECIFICATIONS FOR UTILITY MATERIAL
12.7 Internal secondary leads shall be identified with appropriate markings permanently embossed in the
leads that correspond with lead markings on the nameplate.
12.8 All terminal markings and connections shall be as specified in ANSI Standard C57.12.70, latest
revision.
12.9 All bushing markings shall be either permanently painted on the transformer with
weather/oil/corrosion-resistant paint, or shall be permanently marked on stainless steel plates
riveted, welded, or bolted to the unit. Gummed and/or adhesive labels and/or signs will NOT be
acceptable. Transformer markings other than those specified above are NOT acceptable unless
previously approved by Huntsville Utilities.
13.0 ACCESSORIES
13.1 Each transformer shall be equipped with an externally operated two (2) position, dual voltage switch.
The dual voltage switch handle shall be brought out through the side of the transformer tank for
external operation. The dual voltage switch shall be clearly designated using Huntsville Utilities
approved markings. Switch positions shall be indicated 7200 volts (7.2 kV) or 14400 volts (14.4
kV). In addition, the dual voltage switch shall: (1) clearly indicate its purpose and switch positions;
(2) be easily readable and operable with all conductors in place; (3) be clearly marked for de-
energized operation only. Transformers shall be shipped with the dual voltage switch in the 7200
volt position.
13.2 Each transformer shall be furnished with arrester mounting pads.
13.3 Transformers shall be provided with lifting lugs permanently attached and arranged on the
transformer tank to provide a distributed balanced lift in a vertical direction for the completely
assembled transformer as specified in ANSI Standard C57.12.20, Section 6.2.6.3, latest revision.
13.4 Each transformer shall be equipped with single or two position support lugs (hanger brackets) as
specified in ANSI Standard C57.12.20, Section 6.5, latest revision.
13.5 Each transformer shall be supplied with a durable, metal instruction nameplate as specified by ANSI
Standard C57.12.20, Section 6.3.4, latest revision. Nameplates shall be made of stainless steel or
other approved, non-corrosive metal and permanently marked with essential operating data. The
nameplate shall contain information for Nameplate A as specified in ANSI/IEEE Standard
C57.12.00, Section 5.12, latest revision. Voltage designations shall be in accordance with
ANSI/IEEE Standard C57.12.00, latest revision. The following information shall be included on
the transformer nameplate: (1) the BIL rating of the transformer; (2) decoded date the transformer
is manufactured (Example: MFR DATE 10/17). The nameplate shall be attached to the transformer
with weather/corrosion-resistant fasteners on or immediately adjacent to the lower support lug.
Nameplate shall be readable with all conductors in place.
REVISED R. GRIGG _ DATE 12/20/17 ELECTRIC ENGINEERING
112 SPRAGINS STREET HUNTSVILLE, AL 35801
APPROVED ___________ DATE _______
SINGLE-PHASE, OVERHEAD, DUAL VOLTAGE DISTRIBUTION TRANSFORMER SPECIFICATION EED105.39.10 APPROVED K. HENSLEY____
DATE 12/20/17
PAGE 6 OF 11 GENERAL SPECIFICATIONS FOR UTILITY MATERIAL
13.6 Each transformer shall be provided with a means of relieving excessive pressure as specified in
ANSI Standard C57.12.20, Section 6.2.7, latest revision. The pressure relief device shall
automatically vent when the pressure reaches 10±2 PSIG and reseal when the pressure falls to 6
PSIG. If a self-venting/resealing cover design is utilized, the assembly shall remain effectively
sealed for overloads and external secondary short circuits of the duration and magnitude allowed by
industry standards, but shall vent pressure at a minimum of 8 PSIG and reseal at a minimum of 6
PSIG. Designs which utilize a cover venting system which does not reseal are not permitted. The
completely assembled transformer shall withstand an internal static pressure of 7 PSIG without
permanent distortion. The manufacturer shall certify that design tests have been made on
representative production samples of each diameter to withstand pressure at a rate of rise of one
PSIG per second above 7 PSIG up to the cracking pressure of the pressure relief valve, as specified
in ANSI Standard C57.12.20, Section 6.2.7.1, latest revision, or the pressure at which the cover
design relieves excessive pressure, as specified in ANSI Standard C57.12.20, Section 6.2.7.2, latest
revision, without rupturing or displacing other components of the enclosure. Approved pressure
relief devices or designs must meet or exceed ANSI Standard C57.12.20, Sections 6.2.7 through
6.2.7.3, latest revisions.
13.7 All external markings (kVA markings, switch indications, bushing markings, etc.) shall be either
permanently painted on the unit using weather/oil/corrosion-resistant paint or shall be permanently
marked on stainless steel plates riveted, welded, or bolted to the unit.
13.8 No gummed labels or signs shall be attached to the exterior surface of the transformer, except:
A. Those cited in Section 15.2
B. A label containing the manufacturer’s serial number and Huntsville Utilities’ commodity
number and purchase order number shall be affixed on the top surface of the transformer.
13.9 No warning labels or signs shall be attached to the exterior surface of the transformer.
14.0 TANKS
14.1 Transformer tanks shall be designed per ANSI Standard C57.12.20, latest revision.
14.2 Tank withstand should meet NEMA TR1-1980, Part 2, Page 6, Section D.
14.3 Tank covers shall have a minimum slope of 1.5 to prohibit moisture accumulation.
14.4 Each transformer shall be furnished with tank grounding provisions. Tank grounding provisions
shall be constructed per ANSI Standard C57.12.20, Section 6.5.4, latest revision. Tank grounding
provisions shall be capped before the unit is painted.
15.0 INSULATING OIL
REVISED R. GRIGG _ DATE 12/20/17 ELECTRIC ENGINEERING
112 SPRAGINS STREET HUNTSVILLE, AL 35801
APPROVED ___________ DATE _______
SINGLE-PHASE, OVERHEAD, DUAL VOLTAGE DISTRIBUTION TRANSFORMER SPECIFICATION EED105.39.10 APPROVED K. HENSLEY____
DATE 12/20/17
PAGE 7 OF 11 GENERAL SPECIFICATIONS FOR UTILITY MATERIAL
15.1 Each transformer shall be filled with mineral insulating oil and shall be certified to contain less than
one part per million (1 ppm) Polychlorinated Biphenyls (PCBs) as measured on a dry weight basis.
A notice to this affect shall be included on the transformer nameplate.
EXAMPLE:
FILLED WITH MINERAL OIL CONTAINING LESS
THAN 1 PPM PCBs AT TIME OF MANUFACTURE
or
CONTAINS LESS THAN 1 PPM PCBs
15.2 A separate standard “Non-PCB” label, blue background with white lettering with the following
legend: “Non-PCB Mineral Oil – when manufactured contained less than 1 PPM PCB” shall be
attached on the side opposite the hanger on overhead transformers.
16.0 SHIPPING
16.1 Each transformer shall be placed on a solid wood pallet for shipment. Each transformer shall be
secured to the pallet with two steel bands attached to the transformer lifting provisions in a manner
that prevents damage to the transformer paint finish. Transformers shall not be stacked.
16.2 All single phase transformers must be loaded from the rear of the truck for unloading by forklift
from the rear exit of the trucks trailer.
17.0 LOSS EVALUATIONS
17.1 The following performance information is to be furnished by each transformer manufacturer with
the quotation.
1. No load losses in watts at normal frequency and range.
2. Total full load losses in watts at normal frequency and voltage.
Loss evaluation is an integral factor in the final selection process. The evaluation of losses will be
based on the total cost of ownership for 30 years based on the following formula:
Cost of Ownership = $1.791 x Purchase Price
Plus $7.4206 x No load loss in watts
Plus $3.3393 x Load loss in watts
Where the load losses are computed as
Total loss - No load loss
REVISED R. GRIGG _ DATE 12/20/17 ELECTRIC ENGINEERING
112 SPRAGINS STREET HUNTSVILLE, AL 35801
APPROVED ___________ DATE _______
SINGLE-PHASE, OVERHEAD, DUAL VOLTAGE DISTRIBUTION TRANSFORMER SPECIFICATION EED105.39.10 APPROVED K. HENSLEY____
DATE 12/20/17
PAGE 8 OF 11 GENERAL SPECIFICATIONS FOR UTILITY MATERIAL
18.0 TOLERANCES FOR LOSSES
18.1 The quoted losses shall be guaranteed by the manufacturer as specified in ANSI/IEEE C57.12.00,
Section 9.3, latest revision (IE each unit received, shall be evaluated for load losses on an individual
basis {rather than an average basis} as defined in Paragraphs 17.0 through 20.2.
19.0 LOSS VERIFICATION
19.1 Each manufacturer shall furnish Huntsville Utilities with certified loss test reports, by serial number,
for each unit. Receipt of the certified loss test reports by Huntsville Utilities shall be a
requirement for payment. Each certified test report shall include loss data as specifically required
for quotation as well as size and configuration of each transformer.
19.2 Each certified test report will be reviewed by Huntsville Utilities to ensure that each transformer
conforms to ANSI/IEEE Standard C57.12.00, latest revision.
19.3 Each shipment of distribution transformers received by Huntsville Utilities will be routinely and/or
randomly sampled and loss tested. Huntsville Utilities personnel will compare data obtained
through this loss testing procedure to the data provided by the manufacturer in the certified test
reports. The manufacturer’s certified loss data must be within ±2% of the data obtained by
Huntsville Utilities testing.
19.4 If the loss data obtained by Huntsville Utilities testing is not within ±2% of the manufacturer’s
certified loss data, Huntsville Utilities will choose one or more of the following corrective actions:
a. Conduct loss testing on the entire lot of transformers received by Huntsville Utilities with the
loss testing results being used in place of the certified loss data reported by the manufacturer.
The cost of the loss testing shall be credited to Huntsville Utilities by the respective
manufacturer.
b. Reject the entire lot of transformers and return the transformers to the respective manufacturer
at the manufacturer’s expense.
c. Return a random sampling of the lot of transformers to the respective manufacturer for
verification of the loss test data by the manufacturer.
d. Subject a random sampling of the lot of transformers to testing conducted by a mutually agreed
upon third party test laboratory.
If actions taken under Items c. and d. indicate that the manufacturer’s certified loss data is inaccurate,
the respective manufacturer will bear the expense of the above action(s).
19.5 Any manufacturer whose certified test reports are found to be in error shall be subject to probation,
suspension, and/or deletion as an approved supplier. Such suspension or deletion shall not
REVISED R. GRIGG _ DATE 12/20/17 ELECTRIC ENGINEERING
112 SPRAGINS STREET HUNTSVILLE, AL 35801
APPROVED ___________ DATE _______
SINGLE-PHASE, OVERHEAD, DUAL VOLTAGE DISTRIBUTION TRANSFORMER SPECIFICATION EED105.39.10 APPROVED K. HENSLEY____
DATE 12/20/17
PAGE 9 OF 11 GENERAL SPECIFICATIONS FOR UTILITY MATERIAL
necessarily be limited to a particular item or class of items.
20.0 LOSS ADJUSTMENT PROCEDURES
20.1 Transformer losses shall not exceed tolerances specified in ANSI/IEEE Standard C57.12.00, Section
9.3 - Tolerance for Losses (latest revision). Each transformer that fails to conform to this standard
shall be returned to the manufacturer, freight collect, for replacement. Alternately, Huntsville
Utilities may require credit from the manufacturer equal to the present value of the added cost of
ownership for a 30-year period but not to exceed the original purchase cost of the transformer. The
credit required shall be based on the difference of the actual losses and quoted losses using the
evaluation formula costs.
Example:
Evaluation Definitions: Quoted Values: Actual Values:
PPF Purchase Price Factor = 1.791 Purchase Price = $10.00 Purchase Price = $10.00
NLF No Load Loss Factor = 7.4206 No Load Losses = 1.0 No Load Losses = 1.2
LLF Load Loss Factor = 3.3393 Load Losses = 2 Load Losses = 2.1
Quoted Values Actual Values
Purchase Price times PPF $10.00 * 1.791 = 17.91 $10.00 * 1.791 = 17.91
Plus + +
No load losses times NLF 1.0 * 7.4206 = 7.4206 1.2 * 7.4206 = 8.90472
Plus + +
Load Losses times LLF 2.0 * 3.3393 = 6.6786 2.1 * 3.3393 = 7.01253
Equals Evaluation value = 32.0092 = 33.82725
Quoted evaluation 32.0092
Minus -
Actual evaluation 33.82725
Equals Evaluated Difference 1.81805
Evaluated Difference (1.81805)
Divided by purchase price factor 1.791
Equals Purchase Price Adjustment (1.0151)
Check: re-evaluate units with adjustment to purchase price:
Quoted Purchase Price $10.00
Plus Purchase Price Adjustment (1.0151)
Equals Actual Purchase Price $ 8.9849
Actual Purchase Price times PPF $ 8.9849 * 1.791 = 16.0919559
REVISED R. GRIGG _ DATE 12/20/17 ELECTRIC ENGINEERING
112 SPRAGINS STREET HUNTSVILLE, AL 35801
APPROVED ___________ DATE _______
SINGLE-PHASE, OVERHEAD, DUAL VOLTAGE DISTRIBUTION TRANSFORMER SPECIFICATION EED105.39.10 APPROVED K. HENSLEY____
DATE 12/20/17
PAGE 10 OF 11 GENERAL SPECIFICATIONS FOR UTILITY MATERIAL
Plus +
No load losses times NLF 1.2 * 7.4206 = 8.90472
Plus +
Load Losses times LLF 2.1 * 3.3393 = 7.01253
Equals Evaluation value = 32.00092
This equals the quoted evaluated life cost.
Thus the computed adjustment is accurate.
The required credit would be the 1.0151 or 1.02 if rounded to cents (Since .0051 is greater than .005).
If the adjustment above had been positive, the actual losses would have been less than quoted and no credit
would have been due from the manufacturer. We would not issue a credit to the manufacturer for beating
his loss quotation.
Per ANSI/IEEE Standard C57.12.00, Section 9.3, (latest revision) tolerances for losses are as follows:
Unless otherwise specified, each unit must be within 10% on no load losses and within 6% on load losses.
20.2 Any manufacturer who supplies Huntsville Utilities with transformers that repeatedly fail to meet
quoted losses shall be subject to probation, suspension and/or complete deletion as an approved
supplier.
21.0 EXCEPTIONS AND DEVIATIONS
21.1 Manufacturers quoting transformers to this specification shall indicate any areas where changes to
this design and/or specification are required by their design standards. Any recommended changes
to this design and/or specification offered by the manufacturer shall be accompanied by sufficient
information to permit full evaluation of the desired changes. Any change to this design and/or
specification requires prior approval of Huntsville Utilities Electrical Engineering. Detailed
approval drawings, design criteria, test data, and prototype samples shall be submitted with design
or specification change requests.
21.2 Transformers addressed by these specifications are subject to routine and/or random inspections
and/or testing conducted by Huntsville Utilities to assure that the transformers provided by the
vendor comply with this specification and/or any agreed upon deviations.
21.3 Bids will be awarded to manufacturers based on the manufacturer’s stated compliance with this
specification in its entirety. In the event that a bid is awarded to a manufacturer, and said
manufacturer’s product is discovered not to be in compliance with this specification (and/or any
agreed upon deviations) in any manner, any/all of the following actions will be required by
Huntsville Utilities:
a. Any transformers received that do not comply with this specification in its entirety will be
REVISED R. GRIGG _ DATE 12/20/17 ELECTRIC ENGINEERING
112 SPRAGINS STREET HUNTSVILLE, AL 35801
APPROVED ___________ DATE _______
SINGLE-PHASE, OVERHEAD, DUAL VOLTAGE DISTRIBUTION TRANSFORMER SPECIFICATION EED105.39.10 APPROVED K. HENSLEY____
DATE 12/20/17
PAGE 11 OF 11 GENERAL SPECIFICATIONS FOR UTILITY MATERIAL
rejected and returned to the manufacturer at the manufacturer’s expense.
b. The respective manufacturer will be required to provide Huntsville Utilities with the number
of units initially quoted (at the initial quoted price and loss values) which do comply with
this specification in its entirety. Provision of the initial number of units quoted by the
respective manufacturer is mandatory even if said manufacturer is required to supply units
manufactured by another approved source. Units supplied by another approved source shall
be delivered in the time specified by the manufacturer winning the bid.
c. Failure to comply with these specifications (and/or any agreed upon deviations) in their
entirety may result in the manufacturer’s immediate suspension or removal from Huntsville
Utilities’ list of approved manufacturers. Such suspension or deletion shall not necessarily
be limited to a particular item or class of items.
REVISED R. GRIGG _ DATE 12/20/17 ELECTRIC ENGINEERING
112 SPRAGINS STREET HUNTSVILLE, AL 35801
APPROVED ___________ DATE _______
SINGLE-PHASE, OVERHEAD DISTRIBUTION TRANSFORMER SPECIFICATIONS EED105.39.11 APPROVED K. HENSLEY____
DATE 12/20/17
PAGE 1 OF 13 GENERAL SPECIFICATIONS FOR UTILITY MATERIAL
HUNTSVILLE UTILITIES ELECTRICAL ENGINEERING
SINGLE-PHASE, OVERHEAD, SINGLE VOLTAGE, DISTRIBUTION TRANSFORMER SPECIFICATIONS
PRIMARY VOLTAGE – 7200 OR 14400 (SINGLE VOLTAGE)
SECONDARY VOLTAGE – AS SPECIFIED BY HUNTSVILLE UTILITIES
1.0 SCOPE
1.1 This specification covers the electrical characteristics and mechanical features of single-phase, 60
Hertz, conventional, mineral oil-immersed, self-cooled, single voltage, overhead type, distribution
transformers.
2.0 STANDARDS
2.1 All characteristics, definitions, terminology, etc., except those that are specifically outlined and/or
modified by these specifications, shall be in accordance with ANSI / IEEE Standards C57.12.00,
C57.12.80, and C57.12.90, latest revisions, and ANSI Standards C57.12.20 and C57.12.70, latest
revisions.
3.0 SIZES COVERED
3.1 Transformer sizes covered under this specification include 1 kVA through 500 kVA.
4.0 PRIMARY VOLTAGE
4.1 Transformer primary voltage shall be as specified and/or requested by Huntsville Utilities.
Rated Primary Voltage (Single Voltage)
1) 7200/12470Y
2) 14400/24940Y
5.0 SECONDARY VOLTAGE
5.1 Transformer secondary voltage shall be as specified and/or requested by Huntsville Utilities.
REVISED R. GRIGG _ DATE 12/20/17 ELECTRIC ENGINEERING
112 SPRAGINS STREET HUNTSVILLE, AL 35801
APPROVED ___________ DATE _______
SINGLE-PHASE, OVERHEAD DISTRIBUTION TRANSFORMER SPECIFICATIONS EED105.39.11 APPROVED K. HENSLEY____
DATE 12/20/17
PAGE 2 OF 13 GENERAL SPECIFICATIONS FOR UTILITY MATERIAL
Rated Secondary Voltage (Volts)
1. 120/240
2. 240/480
3. 277
6.0 INSULATION LEVEL
6.1 The high voltage insulation shall be as follows:
Rated High Voltage (Volts) BIL (kV) Insulation Class (kV)
7200/12470Y 95 15
14400/24940Y 125 18
6.2 The low voltage insulation shall have a BIL rating of 30 kV and be of the 1.2 kV insulation class.
7.0 TEMPERATURE RISE LIMITS
7.1 Temperature rise and loading conditions shall conform to ANSI/IEEE Standard C57.12.90,
Section 11, latest revision, and ANSI/IEEE Standard C57.12.00, Section 5.11, latest revision.
8.0 REFERENCE TEMPERATURE
8.1 The reference temperature to which losses, impedance, regulation, and efficiency are corrected
shall be 85C.
9.0 TESTING
9.1 Each transformer shipped to Huntsville Utilities shall pass each and every test specified herein.
9.2 Routine tests shall be conducted on each transformer, and, except as specified in ANSI Standard
C57.12.20, Section 5.2, latest revision, all testing procedures shall follow and/or comply with
ANSI/IEEE Standard C57.12.00 and ANSI/IEEE Standard C57.12.90, latest revisions.
9.3 Each transformer manufacturer shall perform a production line full-wave voltage impulse test of
each unit prior to shipment. Each respective transformer manufacturer shall furnish Huntsville
Utilities with a detailed description of the procedure(s) and test method(s) used during the
execution of each production line impulse test.
REVISED R. GRIGG _ DATE 12/20/17 ELECTRIC ENGINEERING
112 SPRAGINS STREET HUNTSVILLE, AL 35801
APPROVED ___________ DATE _______
SINGLE-PHASE, OVERHEAD DISTRIBUTION TRANSFORMER SPECIFICATIONS EED105.39.11 APPROVED K. HENSLEY____
DATE 12/20/17
PAGE 3 OF 13 GENERAL SPECIFICATIONS FOR UTILITY MATERIAL
9.4 Each manufacturer shall furnish Huntsville Utilities with certified proof, by serial number, that
each transformer design conforms to the short circuit requirements covered in ANSI/IEEE
Standard C57.12.00, Section 7, latest revision, and ANSI/IEEE Standard C57.12.90, Section 12,
latest revision.
9.5 Each manufacturer shall furnish Huntsville Utilities with a certified test report, by serial number,
for each transformer. Each certified test report shall include the following information:
1. Percent impedance; (85 C)
2. Load loss (quoted and actual);
3. No load loss (quoted and actual);
4. Total loss (quoted and actual);
5. Percent excitation current; (@ 100% Voltage)
6. High and low voltage ratings;
7. Serial number of unit;
8. kVA size;
9. Exterior dimensions;
10. Huntsville Utilities purchase order number.
9.6 Each manufacturer shall ship to Huntsville Utilities one (1) copy of each certified test report for
each transformer. Receipt of one (1) copy of each certified test report for each transformer is
a requirement for payment. Certified test reports shall be attached to the invoice for the
transformers:
Invoice To: Huntsville Utilities
Purchasing Department
P.O. Box 2048
Huntsville, AL 35804
10.0 CONSTRUCTION AND DESIGN
REVISED R. GRIGG _ DATE 12/20/17 ELECTRIC ENGINEERING
112 SPRAGINS STREET HUNTSVILLE, AL 35801
APPROVED ___________ DATE _______
SINGLE-PHASE, OVERHEAD DISTRIBUTION TRANSFORMER SPECIFICATIONS EED105.39.11 APPROVED K. HENSLEY____
DATE 12/20/17
PAGE 4 OF 13 GENERAL SPECIFICATIONS FOR UTILITY MATERIAL
10.1 Each transformer shall be constructed and/or designed to meet or exceed construction standards
set forth by ANSI Standard C57.12.20, latest revision.
10.2 All insulating paper used as layer insulation in transformer coil assembly shall be bonded type,
coated on both sides with a thermosetting adhesive and properly cured prior to impregnating with
oil, or the coils shall be wound with primary conductor containing a thermosetting adhesive that
when properly cured will form an effective bond, both turn to turn and layer to layer.
10.3 Transformer core-coil shall be of either shell or core type interlaced design. Shell type non-
interlaced designs are not acceptable.
11.0 TANK FINISH
11.1 Each transformer shall have a light gray (Light Gray No. 70, Munsell Notation 5BG 7.0/0.4 or
equivalent), weather/corrosion-resistant paint finish. Paint shall be of such quality that it meets or
exceeds Proposed EEI Finishing Requirements, latest revision.
11.2 Transformers one hundred (100) kVA and below shall have an insulated coating on the tank cover
capable of withstanding 12 kV at a 2000 volts/second rate of rise or 15 kV at 500 volts/second rate
of rise tested per ASTM D149 using 1/4" diameter electrodes. The results of design tests to
confirm this capability shall be submitted for approval.
11.3 Tank coats on transformers rated 100 kVA and below shall be a finish capable of withstanding a
direct blow of 160 inch-pounds per ASTM D-2794-69.
11.4 For transformers rated above 100 kVA, the minimum acceptable coating shall be a thermosetting
powder 2.5-3.5 MILS thick.
12.0 BUSHINGS AND TERMINALS
12.1 Each transformer shall be provided with cover-mounted, high voltage, wet-process, porcelain
bushing(s) with eyebolt terminals.
12.2 High voltage bushings shall be gasketed and internally clamped to provide a moisture proof and/or
oil proof seal.
12.3 Color of high voltage bushing(s) shall match Light Gray No. 70, Munsell Notation 5BG 7.0/0.4.
12.4 Electrical characteristics, number, location, and physical arrangement of high voltage bushing(s)
shall be as specified in ANSI Standard C57.12.20, Section 6, latest revision.
REVISED R. GRIGG _ DATE 12/20/17 ELECTRIC ENGINEERING
112 SPRAGINS STREET HUNTSVILLE, AL 35801
APPROVED ___________ DATE _______
SINGLE-PHASE, OVERHEAD DISTRIBUTION TRANSFORMER SPECIFICATIONS EED105.39.11 APPROVED K. HENSLEY____
DATE 12/20/17
PAGE 5 OF 13 GENERAL SPECIFICATIONS FOR UTILITY MATERIAL
12.5 Each transformer shall be furnished with low voltage, two-piece, porcelain or glass polyester
bushings with terminals per ANSI Standard C57.12.20, Section 6.1.2, latest revisions.
12.6 Low voltage bushings shall be securely keyed and sealed to prohibit moisture and/or oil migration.
12.7 Electrical characteristics, number, location, and physical arrangement of low voltage terminals
shall be as specified in ANSI Standard C57.12.20, Section 6, latest revision.
12.8 Internal secondary leads shall be identified with appropriate markings permanently embossed in
the leads that correspond with lead markings on the nameplate.
12.9 All terminal markings and connections shall be as specified in ANSI Standard C57.12.70, latest
revision.
12.10 All bushing markings shall be either permanently painted on the transformer with
weather/oil/corrosion-resistant paint, or shall be permanently marked on stainless steel plates
riveted, welded, or bolted to the unit. Gummed and/or adhesive labels and/or signs will NOT be
acceptable. Transformer markings other than those specified above are NOT acceptable unless
previously approved by Huntsville Utilities.
13.0 HIGH VOLTAGE TAPS
13.1 Primary taps shall be supplied on units rated 7200/12470Y only when requested by Huntsville
Utilities.
13.2 All tap changers shall:
a. Conform to all aspects of ANSI Standard C57.12.20, Section 6.2.1, ANSI Standard
C57.12.20, Section 6.2.1.1, and ANSI Standard C57.12.20, Section 6.2.1.2, latest revisions;
b. Be two (2) - 2 ½ % above rated voltage and two (2) - 2 ½ % below rated voltage;
c. Be externally operated;
d. Have the same BIL rating of the highest voltage level when operated at each tap setting;
e. Be provided with positive stops to identify the highest and lowest tap positions;
REVISED R. GRIGG _ DATE 12/20/17 ELECTRIC ENGINEERING
112 SPRAGINS STREET HUNTSVILLE, AL 35801
APPROVED ___________ DATE _______
SINGLE-PHASE, OVERHEAD DISTRIBUTION TRANSFORMER SPECIFICATIONS EED105.39.11 APPROVED K. HENSLEY____
DATE 12/20/17
PAGE 6 OF 13 GENERAL SPECIFICATIONS FOR UTILITY MATERIAL
f. Be designed to prevent accidental operation by requiring a preliminary step such as loosening
a set screw before the tap position can be changed. This positive locking device shall be
clearly visible to field personnel operating the tap changer;
g. Have a permanent, clearly marked indicator plate showing tap positions;
h. Have all external components constructed or weather/corrosion-resistant material;
i. Be designed for operation using hot line tools;
j. Rotate in a clockwise direction from the high tap voltage to a lower tap voltage in the high
voltage winding;
k. Be clearly marked for de-energized operation only.
EXAMPLE: DE-ENERGIZE TRANSFORMER BEFORE
OPERATING TAP CHANGER
13.3 Transformers shall be shipped with the tap changer in the 100% tap position.
13.4 Approved manufacturers of tap changers include Central Moloney, G.E., ABB T&D, Cooper, and
ASP.
14.0 ACCESSORIES
14.1 Each transformer shall be furnished with arrester mounting pads.
14.2 Transformers shall be provided with lifting lugs permanently attached and arranged on the
transformer tank to provide a distributed balanced lift in a vertical direction for the completely
assembled transformer as specified in ANSI Standard C57.12.20, Section 6.2.6.3, latest revision.
14.3 Each transformer shall be equipped with single or two position support lugs (hanger brackets) as
specified in ANSI Standard C57.12.20, Section 6.5, latest revision.
14.4 Each transformer shall be supplied with a durable, metal instruction nameplate as specified by
ANSI Standard C57.12.20, Section 6.3.4, latest revision. Nameplate shall be made of stainless
steel or other approved, non-corrosive metal and permanently marked with essential operating
data. The nameplate shall contain information for Nameplate A as specified in ANSI/IEEE
Standard C57.12.00, Section 5.12, latest revision. Voltage designations shall be in accordance
with ANSI/IEEE Standard C57.12.00, latest revision. The following information shall be included
REVISED R. GRIGG _ DATE 12/20/17 ELECTRIC ENGINEERING
112 SPRAGINS STREET HUNTSVILLE, AL 35801
APPROVED ___________ DATE _______
SINGLE-PHASE, OVERHEAD DISTRIBUTION TRANSFORMER SPECIFICATIONS EED105.39.11 APPROVED K. HENSLEY____
DATE 12/20/17
PAGE 7 OF 13 GENERAL SPECIFICATIONS FOR UTILITY MATERIAL
on the transformer nameplate: (1) the BIL rating of the transformer; (2) decoded date the
transformer is manufactured (Example: MFR DATE 10/17). The nameplate shall be attached to
the transformer with weather/corrosion-resistant fasteners on or immediately adjacent to the lower
support lug. Nameplate shall be readable with all conductors in place.
14.5 Each transformer shall be provided with a means of relieving excessive pressure as specified in
ANSI Standard C57.12.20, Section 6.2.7, latest revision. The pressure relief device shall
automatically vent when the pressure reaches 10±2 PSIG and reseal when the pressure falls to 6
PSIG. If a self-venting/resealing cover design is utilized, the assembly shall remain effectively
sealed for overloads and external secondary short circuits of the duration and magnitude allowed
by industry standards, but shall vent pressure at a minimum of 8 PSIG and reseal at a minimum of
6 PSIG. Designs which utilize a cover venting system which does not reseal are not permitted.
The completely assembled transformer shall withstand an internal static pressure of 7 PSIG
without permanent distortion. The manufacturer shall certify that design tests have been made on
representative production samples of each diameter to withstand pressure at a rate of rise of one
PSIG per second above 7 PSIG up to the cracking pressure of the pressure relief valve, as specified
in ANSI Standard C57.12.20, Section 6.2.7.1, latest revision, or the pressure at which the cover
design relieves excessive pressure, as specified in ANSI Standard C57.12.20, Section 6.2.7.2,
latest revision, without rupturing or displaying other components of the enclosure. Approved
pressure relief devices or designs must meet or exceed ANSI Standard C57.12.20, Sections 6.2.7
through 6.2.7.3, latest revisions.
14.6 All external markings (kVA markings, switch indications, bushing markings, etc.,) shall be either
permanently painted on the unit using weather/oil/corrosion-resistant paint or shall be permanently
marked on stainless steel plates riveted, welded, or bolted to the unit.
14.7 No gummed labels or signs shall be attached to the exterior surface of the transformer, except:
1. Those cited in Section 16.2
2. A label containing the manufacturer’s serial number and Huntsville Utilities’ commodity
number and purchase order number shall be affixed on the top surface of the transformer.
14.8 No warning labels or signs shall be attached to the exterior surface of the transformer.
15.0 TANKS
15.1 Transformer tanks shall be designed per ANSI Standard C57.12.20, latest revision.
15.2 Tank withstand should meet NEMA TR1-1980, Part 2, Page 6, Section D.
REVISED R. GRIGG _ DATE 12/20/17 ELECTRIC ENGINEERING
112 SPRAGINS STREET HUNTSVILLE, AL 35801
APPROVED ___________ DATE _______
SINGLE-PHASE, OVERHEAD DISTRIBUTION TRANSFORMER SPECIFICATIONS EED105.39.11 APPROVED K. HENSLEY____
DATE 12/20/17
PAGE 8 OF 13 GENERAL SPECIFICATIONS FOR UTILITY MATERIAL
15.3 Tank covers shall have a minimum slope of 1.5 to prohibit moisture accumulation.
15.4 Each transformer shall be furnished with tank grounding provisions. Tank grounding provisions
shall be constructed per ANSI Standard C57.12.20, Section 6.5.4, latest revision. Tank grounding
provisions shall be capped before the unit is painted.
16.0 INSULATING OIL
16.1 Each transformer shall be filled with mineral insulating oil and shall be certified to contain less
than one part per million (1 ppm) Polychlorinated Biphenyls (PCBs) as measured on a dry weight
basis. A notice to this affect shall be included on the transformer nameplate.
EXAMPLE:
FILLED WITH MINERAL OIL CONTAINING LESS
THAN 1 PPM PCBs AT TIME OF MANUFACTURE
or
CONTAINS LESS THAN 1 PPM PCBs
16.2 A separate standard “Non-PCB” label, blue background with white lettering with the following
legend: “Non-PCB Mineral Oil – when manufactured contained less than 1 PPM PCB” shall be
attached on the side opposite the hanger on overhead transformers.
17.0 SHIPPING
17.1 Each transformer shall be placed on a solid wood pallet for shipment. Each transformer shall be
secured to the pallet with two steel bands attached to the transformer lifting provisions in a manner
that prevents damage to the transformer paint finish. Transformers shall not be stacked.
17.2 All single phase transformers must be loaded from the rear of the truck for unloading by forklift
from the rear exit of the trucks trailer.
18.0 LOSS EVALUATIONS
18.1 The following performance information is to be furnished by each transformer manufacturer with
the quotation.
REVISED R. GRIGG _ DATE 12/20/17 ELECTRIC ENGINEERING
112 SPRAGINS STREET HUNTSVILLE, AL 35801
APPROVED ___________ DATE _______
SINGLE-PHASE, OVERHEAD DISTRIBUTION TRANSFORMER SPECIFICATIONS EED105.39.11 APPROVED K. HENSLEY____
DATE 12/20/17
PAGE 9 OF 13 GENERAL SPECIFICATIONS FOR UTILITY MATERIAL
a. No load losses in watts at normal frequency and voltage.
b. Total full load losses in watts at normal frequency and voltage.
Loss evaluation is an integral factor in the final selection process. The evaluation of losses will be
based on the total cost of ownership for 30 years based on the following formula:
Cost of Ownership = $1.791 x Purchase Price
Plus $7.4206 x No load loss in watts
Plus $3.3393 x Load loss in watts
Where the load losses are computed as
Total loss - No load loss
19.0 TOLERANCES FOR LOSSES
19.1 The quoted losses shall be guaranteed by the manufacturer as specified in ANSI/IEEE C57.12.00-
1987, Section 9.3. Average of all units is interpreted to mean all units in a single manufacturing
run delivered to Huntsville Utilities in a single shipment. Split shipments shall be evaluated
separately.
20.0 LOSS VERIFICATION
20.1 Each manufacturer shall furnish Huntsville Utilities with certified loss test reports, by serial
number, for each unit. Receipt of the certified loss test reports by Huntsville Utilities shall be a
requirement for payment. Each certified test report shall include loss data as specifically required
for quotation as well as size and configuration of each transformer.
20.2 Each certified test report will be reviewed by Huntsville Utilities to ensure that each transformer
conforms to ANSI/IEEE Standard C57.12.00, latest revision.
20.3 Each shipment of distribution transformers received by Huntsville Utilities will be routinely and/or
randomly sampled and loss tested. Huntsville Utilities personnel will compare data obtained
through this loss testing procedure to the data provided by the manufacturer in the certified test
reports. The manufacturer’s certified loss data must be within ±2% of the data obtained by
Huntsville Utilities testing.
20.4 If the loss data obtained by Huntsville Utilities testing is not within ±2% of the manufacturer’s
certified loss data, Huntsville Utilities will choose one or more of the following corrective actions:
REVISED R. GRIGG _ DATE 12/20/17 ELECTRIC ENGINEERING
112 SPRAGINS STREET HUNTSVILLE, AL 35801
APPROVED ___________ DATE _______
SINGLE-PHASE, OVERHEAD DISTRIBUTION TRANSFORMER SPECIFICATIONS EED105.39.11 APPROVED K. HENSLEY____
DATE 12/20/17
PAGE 10 OF 13 GENERAL SPECIFICATIONS FOR UTILITY MATERIAL
a. Conduct loss testing on the entire lot of transformers received by Huntsville Utilities with
the loss testing results being used in place of the certified loss data reported by the
manufacturer. The cost of the loss testing shall be credited to Huntsville Utilities by the
respective manufacturer.
b. Reject the entire lot of transformers and return the transformers to the respective manufacturer
at the manufacturer's expense.
c. Return a random sampling of the lot of transformers to the respective manufacturer for
verification of the loss test data by the manufacturer.
d. Subject a random sampling of the lot of transformers to testing conducted by a mutually
agreed upon third party test laboratory.
If actions taken under Items c. and d. indicate that the manufacturer's certified loss data is
inaccurate, the respective manufacturer will bear the expense of the above action(s).
20.5 Any manufacturer whose certified test reports are found to be in error shall be subject to probation,
suspension, and/or deletion as an approved supplier. Such suspension or deletion shall not
necessarily be limited to a particular item or class of items.
21.0 LOSS ADJUSTMENT PROCEDURES
21.1 Transformer losses shall not exceed tolerances specified in ANSI/IEEE Standard C57.12.00,
Section 9.3 - Tolerances for Losses (latest revision). Each transformer that fails to conform to this
standard shall be returned to the manufacturer, freight collect, for replacement. Alternately,
Huntsville Utilities may require credit from the manufacturer equal to the present value of the
added cost of ownership for a 30-year period but not to exceed the original purchase cost of the
transformer. The credit required shall be based on the difference of the actual losses and quoted
losses using the evaluation formula costs.
Example:
Evaluation Definitions: Quoted Values: Actual Values:
PPF Purchase Price Factor = 1.791 Purchase Price = $10.00 Purchase Price = $10.00
NLF No Load Loss Factor = 7.4206 No Load Losses = 1.0 No Load Losses = 1.2
LLF Load Loss Factor = 3.3393 Load Losses = 2.0 Load Losses = 2.1
Quoted Values Actual Values
REVISED R. GRIGG _ DATE 12/20/17 ELECTRIC ENGINEERING
112 SPRAGINS STREET HUNTSVILLE, AL 35801
APPROVED ___________ DATE _______
SINGLE-PHASE, OVERHEAD DISTRIBUTION TRANSFORMER SPECIFICATIONS EED105.39.11 APPROVED K. HENSLEY____
DATE 12/20/17
PAGE 11 OF 13 GENERAL SPECIFICATIONS FOR UTILITY MATERIAL
Purchase Price times PPF $10.00 * 1.791 = 17.91 $10.00 * 1.791 = 17.91
Plus + +
No load losses times NLF 1.0 * 7.4206 = 7.4206 1.2 * 7.4206 = 8.90472
Plus + +
Load Losses times LLF 2.0 * 3.3393 = 6.6786 2.1 * 3.3393 = 7.01253
Equals Evaluation value = 32.0092 = 33.82725
Quoted evaluation 32.0092
Minus Actual evaluation -33.82725
Equals Evaluated Difference = 1.81805
Evaluated Difference (1.81805)
Divided by purchase price factor 1.791
Equals Purchase Price Adjustment =(1.0151)
Check: re-evaluate units with adjustment to purchase price:
Quoted Purchase Price $10.00
Plus Purchase Price Adjustment +( 1.0151)
Equals Actual Purchase Price =$ 8.9849
Actual Purchase Price times PPF $ 8.9849 * 1.791 = 16.0919559
Plus +
No load losses times NLF 1.2 * 7.4206 = 8.90472
Plus +
Load Losses times LLF 2.1 * 3.3393 = 7.01253
Equals Evaluation value = 32.00092
This equals the quoted evaluated life cost.
Thus the computed adjustment is accurate.
The required credit would be the 1.0151 or 1.02 if rounded to cents
(since .0051 is greater than .005).
If the adjustment above had been positive, the actual losses would have been less than quoted and no credit
would have been due from the manufacturer.
We would not issue a credit to the manufacturer for beating his loss quotation.
Per ANSI/IEEE Standard C-57.12.00, Section 9.3, tolerances for losses are as follows:
Number of No-load Load
REVISED R. GRIGG _ DATE 12/20/17 ELECTRIC ENGINEERING
112 SPRAGINS STREET HUNTSVILLE, AL 35801
APPROVED ___________ DATE _______
SINGLE-PHASE, OVERHEAD DISTRIBUTION TRANSFORMER SPECIFICATIONS EED105.39.11 APPROVED K. HENSLEY____
DATE 12/20/17
PAGE 12 OF 13 GENERAL SPECIFICATIONS FOR UTILITY MATERIAL
Units on Basis of Losses Losses
One Order Determination (%) (%)
1 1 10 6
2 or more Each unit 10 6
2 or more Average of 0 0
all units
Therefore, each unit must be within 10% on no load losses and within 6% on load losses. If more than
one identical unit is shipped as one order in a single shipment, the average of all units must meet quoted
losses with no tolerance.
21.2 Any manufacturer who supplies Huntsville Utilities with transformers that repeatedly fail to meet
quoted losses shall be subject to probation, suspension, and/or complete deletion as an approved
supplier.
22.0 EXCEPTIONS AND DEVIATIONS
22.1 Manufacturers quoting transformers to this specification shall indicate any areas where changes
to this design and/or specification are required by their design standards. Any recommended
changes to this design and/or specification offered by the manufacturer shall be accompanied by
sufficient information to permit full evaluation of the desired changes. Any change to this design
and/or specification requires prior approval from Huntsville Utilities Electrical Engineering.
Detailed approval drawings, design criteria, test data, and prototype samples shall be submitted
with design or specification change requests.
22.2 Transformers addressed by these specifications are subject to routine and/or random inspections
and/or testing conducted by Huntsville Utilities to assure that the transformers provided by the
vendor comply with this specification and/or any agreed upon deviations.
22.3 Bids will be awarded to manufacturers based on the manufacturer's stated compliance with this
specification in its entirety. In the event that a bid is awarded to a manufacturer, and said
manufacturer's product is discovered not to be in compliance with this specification (and/or any
agreed upon deviations) in any manner, any/all of the following actions will be required by
Huntsville Utilities:
a. Any transformers received that do not comply with this specification in its entirety will be
rejected and returned to the manufacturer at the manufacturer's expense.
REVISED R. GRIGG _ DATE 12/20/17 ELECTRIC ENGINEERING
112 SPRAGINS STREET HUNTSVILLE, AL 35801
APPROVED ___________ DATE _______
SINGLE-PHASE, OVERHEAD DISTRIBUTION TRANSFORMER SPECIFICATIONS EED105.39.11 APPROVED K. HENSLEY____
DATE 12/20/17
PAGE 13 OF 13 GENERAL SPECIFICATIONS FOR UTILITY MATERIAL
b. The respective manufacturer will be required to provide Huntsville Utilities with the number
of units initially quoted (at the initial quoted price and loss values) which do comply with this
specification in its entirety. Provision of the initial number of units quoted by the respective
manufacturer is mandatory even if said manufacturer is required to supply units manufactured
by another approved source. Units supplied by another approved source shall be delivered in
the time specified by the manufacturer winning the bid.
c. Failure to comply with this specification (and/or any agreed upon deviations) in their entirety
may result in the manufacturer's immediate suspension or removal from Huntsville Utilities'
list of approved manufacturers. Such suspension or deletion shall not necessarily be limited
to a particular item or class of items.