ENGINEERING SPECIFICATION

Transcription

1 ENGINEERING SPECIFICATION No. Page 1 CATEGORY: TRANSFORMERS DATE: 11/16/2006 Subject: TABLE OF CONTENTS PURPOSE...2 SCOPE...2 REFERENCES...2 DEFINITIONS...2 SPECIFICATION...2 General... 2 High Voltage Bushings...4 Dielectric Fluid...4 Transformer Labeling...6 TECHNICAL INFORMATION...7 TESTING AND INSPECTION...8 LOSS EVALUATION...8 DRAWINGS...10 MATERIAL AND DESIGN CHANGES...10 TABLE

2 Page 2 1 PURPOSE Provides the technical requirements for the submittal of a bid to manufacture Overhead- Type Distribution Transformers for District use. 2 SCOPE 2.1 These specifications cover the electrical and mechanical features of a single phase, 60 Hz, liquid filled, self cooled, overhead-type transformer (unit). 2.2 The unit shall conform to all applicable provisions of the American National Standards Institute Standard No. C , latest revision except as denoted by provisions of this specification. 3 REFERENCES 3.1 IEEE C General Requirements for Liquid Immersed Distribution, Power and Regulating Transformers 3.2 ANSI/ASTM D-3487, Standard Specification for Mineral Insulating Oil 3.3 ASTM D-6871, Standard Specification for Natural (Vegetable Oil) Ester Fluids used in Electrical Apparatus 3.4 ANSI C , Overhead-Type Distribution Transformers 3. IEEE C , PART I: Standard Test Code for Liquid Immersed Distribution, Power and Regulating Transformers 3.6 ASTM 13, Standard Practice for Specifying Color by the Munsell System 4 DEFINITIONS Refer to the IEEE Standard Dictionary of Electrical and Electronic Terms. SPECIFICATION.1 General.1.1 The transformer shall be manufactured, tested and delivered in accordance with the applicable industry standards, latest revisions, as defined in Section 3; unless specifically addressed otherwise in this specification or in writing by the SMUD Standards Engineer.

3 Page The transformer shall be rated single-phase, 60 Hertz, self-cooled 6 o C rise, oil immersed, continuous duty, distribution type with no high voltage taps required..1.3 The unit shall have one of the following high-voltage ratings as specified in the bid document: 6930/12,000 GrdY volts 4160x12,000/20,784 GrdY volts 12,000/20,784 GrdY volts 4160 volts 2400/4160 GrdY volts.1.4 The low voltage winding will be specified elsewhere as 120/240 volts, 240/480 volts, or 277 volts..1. Transformers rated 2400/4160 GrdY volts or 4160 volts shall have a minimum BIL of 60kV. Units with a high-voltage rating of 6930/12,000 GrdY volts shall have a minimum BIL of 9 kv. Units rated 12,000/20784 GrdY volts shall have a minimum BIL of 12 kv. Transformers with dual voltage ratings shall meet the minimum BIL requirements of the higher primary voltage rating, as outlined above..1.6 Units rated 4160x12,000/20,784 GrdY volts shall be supplied with an externally operable dual voltage switch to change the internal winding connections to obtain either of the two high voltage ratings..1.7 All units supplied under this specification shall be supplied with a nameplate that meets the requirements of ANSI C and providing information as specified in ANSI C , latest revision..1.8 The tank finish shall be of a Light Gray color, conforming to ANSI No. 70 (Munsell No. BG 7.0/0.4)..1.9 The dimensions and/or weight of transformers shall not exceed the values specified in Table 1, Section 11 of this specification, except as allowed in writing by the SMUD Standards Engineer Units shall have supporting lugs as specified in ANSI C , Section 7..2, except that 0kVA, 4160x12,000/20,784GrdY volt rated transformers shall have Type B supporting lugs with Type B spacing, as shown in Figures 1 and 3 of ANSI Standard C

4 Page To limit pressure buildup inside the tank, an automatic pressure relief device shall be installed on each transformer. The pressure relief system shall be designed to conform with ANSI Standard C , Section 7..2 and High Voltage Bushings.2.6 Each transformer shall be supplied with two cover-mounted high voltage bushings with the capability of being disconnected from the transformer windings at or below the bottom of the bushings, inside the tank..2.7 The high voltage bushing terminals shall not be manufactured of cast aluminum. The eyebolt for the terminal shall have a threaded length of 1 inch, and shall be Penn-Union Electric Company Part No. S46906, or District approved equal..2.8 The high voltage bushing terminals shall be equipped with bird guards so that there are no exposed conducting parts when energized. The bird guard shall be GE catalog No. 1921J060P21, Cooper Catalog No. 229C06 or District approved equal..2.9 All bushings shall have Light Gray ANSI No. 70 (Munsell No. BG 7.0/0.4) finish..3 Dielectric Fluid.3.1 The transformer design shall accommodate both a natural ester-based dielectric fluid meeting the requirements of paragraphs.3. and.3.6, or a mineral oil dielectric fluid as described in paragraph.3.7. The transformer shall meet all other requirements of this specification when filled with either dielectric fluid. The fluid to be provided shall be specified in the bid document..3.2 The transformer shall be shipped completely filled with a dielectric fluid that has received approval by the District. The Bidder shall specify the brand and name of the dielectric fluid that will be supplied..3.3 There shall be no residue of dielectric fluid on the exterior of the transformer when the unit is delivered to the District. This includes, but is not limited to residue resulting from the filling process, fluid that might be expelled by pressure relief devices during transport, fluid from tank leaks, or fluid that drips from wetted seals around the tank cover..3.4 The supplied fluid shall be miscible with existing acid refined mineral oil dielectric fluids, as identified in paragraph.3.7, and with Envirotemp FR3

5 fluid produced by Cooper Power Systems.. Page.3. Envirotemp FR3 fluid is approved for use by the District. If the Bidder will supply a different natural ester dielectric, the electrical, chemical and physical characteristics of the fluid, pertinent to application in distribution transformers, shall be provided to the District for approval. The Bidder shall provide support documentation including the Material Safety Data Sheet, certified test results and/or EPA reports, as required for the District to perform a thorough evaluation of the specified fluid in accordance with these requirements..3.6 The natural ester-based dielectric fluid shall meet the minimum requirements of ASTM Standard D-6871 and shall have the following minimum characteristics: Dielectric Constant, ASTM C >3 Dielectric Breakdown, ASTM 1816 (0.04 gap/after filling) >2kV Flash and Fire Point: >300 C Viscosity, ASTM C <=4cSt The fluid shall be acceptable for use in the State of California, and shall be certified non-toxic, non-bioaccumulating, non-carcinogenic, and 100% biodegradable in the environment. The Bidder shall supply data from accelerated aging tests showing that the fluid significantly improves the longevity of the transformer winding insulation relative to mineral oil dielectric fluid. Tests results shall suggest a minimum doubling of the paper insulation life in transformers filled with the natural ester-based fluid as compared to conventional mineral oil dielectric fluid. The fluid shall retain electrical, chemical and physical characteristics so as to perform acceptably in service with a water content less than 400mg/kg. The fluid shall retain greater than 90% of it s dielectric strength and fire point when contaminated with mineral oil fluid or other natural-ester based dielectric fluid in percentages less than 7.% by weight. The properties and characteristics of the natural ester-based dielectric fluid shall be such that the equipment used for handling of mineral oil dielectric fluid, as described in paragraph.3.7 of this specification, may be used to transfer, filter, dry and/or reclaim the fluid..3.7 Mineral oil dielectric fluid shall be Type II anti-oxidant inhibited mineral oil, in compliance with the latest revision of ANSI/ASTM D-3487, Standard Specification for Mineral Insulating Oil used in Electrical Apparatus.

6 Page Dielectric fluids shall be properly handled, prepared and filtered before adding to clean dry transformers. When natural ester dielectric is supplied, the fluid shall not be contaminated with mineral oil dielectric residue, such a may remain in transfer piping, or filter equipment if improperly purged. (Separate oil handling facilities and processes are recommended, to prevent cross contamination of natural ester and mineral oil dielectric fluids.) After filling, transformer shall be sealed and may be topped with a nitrogen blanket as recommended by the manufacturer..3.9 Certification must be provided stating that the dielectric fluid is free of polychlorinated biphenyls (PCB's.).3.9 The nameplate of the transformer shall specify that the dielectric fluid is free of polychlorinated biphenyls (PCB s). The preferred designation on the nameplate is Contains No PCB at Time of Manufacture. Other designations will require approval by the District s Standards Engineer The Contractor shall provide the District with characteristics of the dielectric fluid that is used to fill the transformer(s) at the time of manufacture. The District may test the fluid upon delivery and will use the supplied characteristics and the requirements of this specification as criteria for acceptance of the transformer Fluids that do not meet these requirements may only be furnished upon approval by the District..4 Transformer Labeling.4.1 The transformer instruction nameplate shall be of corrosion-resistant material meeting the requirements of ANSI C Section The following information shall also be shown on the instruction nameplate of all units: Basic Lightning Impulse Insulation Level (BIL) Gallons of insulating liquid Approximate total weight in pounds Statement of PCB content per paragraph.3.9 Dual voltage switch positions 4 kv and 12 kv shall be identified on the instruction nameplate drawing..4.2 The 4 kv and 12 kv positions of the dual voltage switch shall be indicated on the tank exterior with a stencil or stainless steel indicating plate..4.3 Where natural ester-based dielectric fluid is supplied, the transformer will be

7 Page 7 marked with a permanent decal designating the brand name of the fluid, and stipulating that the fluid is biodegradable. The decal shall be clearly visible when the transformer is installed..4. The transformer shall be labeled with a decal that reads "NON-PCB". The decal shall be durable and appropriate for outdoor application. The decal shall be approximately 2-1/2" H x 3-1/2"W. It shall be blue with white lettering and have a gloss finish. The letters shall be 1" high and approximately 1/2" wide. The decal shall be located 3" above the bottom of the tank, under the low voltage bushings, and directly across from the transformer mounting brackets. 6 TECHNICAL INFORMATION 6.1 Each bidder shall submit with the bid the following descriptive information for each rating of transformer: Dimensioned outline drawings; Transformer net weights; Part number for externally operable dual voltage switch, when required; Guaranteed performance data: Ratings Temperature rise at rated load Percent regulation at rated load - 100% power factor Percent regulation at rated load - 80% power factor Percent impedance Percent exciting current Average no-load and load losses 6.2 Cooper Envirotemp FR3 fluid is presently approved by the District. If the bidder will supply a different fluid, the complete electrical, chemical and physical characteristics of the supplied natural ester-based dielectric fluid relevant to use in distribution transformers, as well as a current MSDS for the fluid shall be supplied, as per Section.3 of this specification. Also, the bidder shall provide certified test results or EPA reports showing that the fluid is biodegradable, non-toxic, noncarcinogenic, and non-bioaccumulating, and accelerated aging test results showing that the fluid will extend the life of transformer paper insulation as identified in Section.7.. The District will approve the proposed fluid before bid award. 6.4 It shall be expressly understood that the technical information, as furnished by the successful bidder, shall constitute guarantees, with variance therefrom only insofar as allowable by applicable NEMA and ANSI Standard tolerances.

8 Page 8 6. Quoted losses should be realistic values based on experience with tested designs, and therefore shall be guaranteed with certainty. 7 TESTING AND INSPECTION 7.1 Prior to shipment, each transformer shall have passed the following routine tests in accordance with ANSI Standards: Applied and induced voltage; No-load losses Load Losses Ratio Polarity Exciting current 7.2 A Certified Test Report of the above tests shall be supplied to the District for each unit to be delivered under this specification. Test reports must reach the District on or before the date of delivery of the units shipped, as this will be a basis for acceptance of the shipment. 8 LOSS EVALUATION 8.1 Each bidder shall submit guaranteed no-load losses and load losses at the rated kva for each bid item. 8.2 The District will evaluate the guaranteed losses at he following rates to determine the equivalent first cost of losses for each bid item: No-load losses $.90/W Load losses (total losses minus no-load losses) $ 1.06/W The equivalent first cost for owning and operating the transformers (sum of the evaluated bid price, California state sales tax, and the equivalent first cost of no-load losses and load losses) will be one criterion used to determine the successful bidder. 8.3 The Contractor shall test each manufactured transformer to determine no-load losses, load losses and total losses, in accordance with the requirements of ANSI C and C , latest revisions. Test data shall be certified as correct and submitted to the District prior to or at the time of shipment. Test data shall be submitted by to the District s assigned Standards Engineer and to the District s Material Coordinator. Data shall be submitted in Excel spreadsheet (.xls) or comma delimited (.csv) format. The District must approve alternate methods of submittal.

9 Page 9 In addition, the certified test reports shall be sent under a separate cover to: Sacramento Municipal Utility District Supply Chain Services Department ATTN: Procurement Professional, B203 P.O. Box 1830 Sacramento, CA For long-term contracts the District will review tested transformer losses at the end of each calendar quarter. Otherwise, the District will review losses at the time of each order shipment. The District will compare the average of the certified test losses for each bid item, against the guaranteed average losses quoted in the bid. Where the average of the tested no-load losses or load losses for a bid item exceeds the quoted bid item commitment, the Contractor will pay the evaluated total difference to the District. The costs of losses used for evaluating the total difference shall be in accordance with paragraph 8.2 of this specification. 8. Bonuses will not be awarded for bid items with evaluated average losses that are less than the losses quoted at the time of bid. Losses, and the associated equivalent first costs, will not be balanced between transformers with different ratings. 8.6 In addition, the District may reject any transformer with no-load losses or total losses that exceed the guaranteed losses by more than the standard ANSI tolerances listed below: No-load losses 10% Total losses at rated kva 6% 8.7 The Contractor shall contact the District's assigned Material Coordinator before shipping any unit with tested losses that exceed the above tolerances. The District may reject such transformers. If the District accepts delivery of such units, the Contractor will be penalized at the following rates for all excess losses (tested losses minus guaranteed losses) for each unit accepted. No-load losses Load losses at rated kva $ 11.80/W $ 2.12/W 9 DRAWINGS 9.1 Final drawings and technical data shall be submitted to the District s Standards Engineer for review and approval, prior to award for manufacturing or supply. An

10 Page 10 electronic version of the final drawings and documents shall be provided to the District Standards Engineer in Adobe Acrobat (*.pdf), Microsoft Word (*.doc), and/or AutoCAD (*.dwg) format. 9.2 Drawings shall include the following: Detailed dimensional drawing of the unit showing location of exterior devices and required clearances. Detailed drawing of high voltage bushing terminal connector. Parts list including catalog numbers. Nameplate Drawing 9.3 All required submittals shall be complete and shall be approved by the District's Standards Engineer before final award of contracts. Any submittal that is not complete may result in technical non-compliance. 10 MATERIAL AND DESIGN CHANGES Following approval by the District of the specific design(s) and materials submitted to the District by the supplier, the supplier shall not make changes in such design(s) or materials without approval of the District s Standards Engineer.

11 Page TABLE 1 MAXIMUM SIZE AND WEIGHT SINGLE PHASE OVERHEAD-TYPE DISTRIBUTION TRANSFORMERS A. All units except those with 4160x12,000/20,784 GRDY V primary rating: kva Height (in.) Width (in.) Depth (in.) Weight (lbs.) B. Units with 4160x12,000/20,784 GRDY V primary rating: kva Height (in.) Width (in.) Depth (in.) Weight (lbs.)