VA 26 12 19-2010 PAD-MOUNTED LIQUID-FILLED MEDIUM-VOLTAGE TRANSFORMERS.pdf

1、09-10 26 12 19 - 1 SECTION 26 12 19 PAD-MOUNTED, LIQUID-FILLED, MEDIUM-VOLTAGE TRANSFORMERS SPEC WRITER NOTE: Delete between /-/ if not applicable to project. This spec is applicable for transformers 2500 kVA and less on 5 kV and 15 kV systems, with source not over 8.3 kV phase-to ground. PART 1 - G

2、ENERAL 1.1 DESCRIPTION A. This section specifies the furnishing, installation, and connection of pad-mounted transformers. B. Pad-mounted transformers shall be complete, outdoor type, continuous duty, integral assembly, grounded, tamper-resistant, and weatherproof, with liquid-immersed transformers.

3、 1.2 RELATED WORK A. Section 09 06 00, SCHEDULE FOR FINISHES: Finishes for electrical equipment. /B. Section 13 05 41, SEISMIC RESTRAINT REQUIREMENTS FOR NON-STRUCTURAL COMPONENTS: Requirements for seismic restraint of non-structural components./ C. Section 26 05 11, REQUIREMENTS FOR ELECTRICAL INST

4、ALLATIONS: General electrical requirements that are common to more than one section of Division 26. D. Section 26 05 13, MEDIUM-VOLTAGE CABLES: Medium-voltage cables. E. Section 26 05 26, GROUNDING AND BONDING FOR ELECTRICAL SYSTEMS: Requirements for personnel safety and to provide a low impedance p

5、ath to ground for possible ground currents. F. Section 26 05 41, UNDERGROUND ELECTRICAL CONSTRUCTION: Manholes, pull-boxes, and duct lines for underground raceway systems. G. Section 26 05 71, ELECTRICAL SYSTEM PROTECTIVE DEVICE STUDY: Short-circuit and coordination study. 1.3 QUALITY ASSURANCE Refe

6、r to Paragraph, QUALIFICATIONS, in Section 26 05 11, REQUIREMENTS FOR ELECTRICAL INSTALLATIONS. 1.4 FACTORY TESTS Transformers shall be thoroughly tested at the factory to ensure that there are no electrical or mechanical defects. Tests shall be conducted as per UL and ANSI Standards. Factory tests

7、shall be certified. The following tests shall be performed: 1. Perform insulation-resistance tests, winding-to-winding and each winding-to-ground. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-09-10 26 12 19 - 2 2. Perform turns-ratio tests at all

8、tap positions. 1.5 SUBMITTALS A. In accordance with Section 26 05 11, REQUIREMENTS FOR ELECTRICAL INSTALLATIONS, submit the following: B. Shop Drawings: 1. Clearly present sufficient information to determine compliance with drawings and specifications. 2. Include electrical ratings, nameplate data,

9、impedance, outline drawing with dimensions and front, top, and side views, weight, mounting details, decibel rating, termination information, temperature rise, no-load and full-load losses, regulation, overcurrent protection, connection diagrams, and accessories. 3. Complete nameplate data, includin

10、g manufacturers name and catalog number. C. Manuals: 1. When submitting the shop drawings, submit companion copies of complete maintenance and operating manuals, including technical data sheets, wiring diagrams, and information for ordering replacement parts. a. Identify terminals on wiring diagrams

11、 to facilitate installation, maintenance, and operation. b. Indicate on wiring diagrams the internal wiring for each piece of equipment and interconnections between the pieces of equipment. c. Approvals will be based on complete submissions of manuals, together with shop drawings. 2. Two weeks prior

12、 to the final inspection, submit four copies of the final up-dated maintenance and operation manuals to the /Resident Engineer/ /COTR/. a. Update the manual to include any information necessitated by shop drawing approval. b. Show all terminal identification. c. Include information for testing, repa

13、ir, trouble-shooting, assembly, disassembly, and recommended maintenance intervals. d. Provide a replacement parts list with current prices. Include a list of recommended spare parts, tools, and instruments for testing and maintenance purposes. e. Furnish manuals in loose-leaf binder or manufacturer

14、s standard binder. D. Certifications: Two weeks prior to the final inspection, submit four copies of the following certifications to the /Resident Engineer/ /COTR/: Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-09-10 26 12 19 - 3 1. Certification b

15、y the manufacturer that the materials conform to the requirements of the drawings and specifications. 2. Certification by the contractor that the materials have been properly installed, connected, and tested. 1.6 APPLICABLE PUBLICATIONS A. Publications listed below (including amendments, addenda, re

16、visions, supplements, and errata) form a part of this specification to the extent referenced. Publications are referenced in the text by designation only. B. American Concrete Institute (ACI): 318-05 . Building Code Requirements for Structural Concrete C. American National Standards Institute (ANSI)

17、: C37.47-00 High Voltage Current-Limiting Type Distribution Class Fuses and Fuse Disconnecting Switches C57.12.00-00 . General Requirements for Liquid-Immersed Distribution, Power and Regulating Transformers C57.12.25-90 . Transformers-Pad-Mounted, Compartmental-Type, Self Cooled, Single-Phase Distr

18、ibution Transformers with Separable Insulated High Voltage Connectors; High Voltage, 34500 Grd Y/19920 Volts and Below; Low-Voltage 240/120 Volts; 167 kVA and Smaller Requirements C57.12.28-05 . Pad-Mounted Equipment Enclosure Integrity C57.12.29-99 . Pad-Mounted Equipment Enclosure Integrity for Co

19、astal Environments C57.12.34-04 . Pad-Mounted, Compartmental-Type, Self Cooled, Three-Phase Distribution Transformers, 2500kVA and Smaller High Voltage 34500 Grd Y/19920 Volts and Below; Low-Voltage 480 Volts and Below D. American Society for Testing and Materials (ASTM): D3487-08 . Standard Specifi

20、cation for Mineral Insulating Oil Used in Electrical Apparatus E. Institute of Electrical and Electronic Engineers (IEEE): C2-07 National Electrical Safety Code C62.11-99 Metal-Oxide Surge Arresters for Alternating Current Power Circuits 48-09 Test Procedures and Requirements for Alternating Current

21、 Cable Terminations Used on Shielded Cables Having Laminated Insulation Rated 2.5kV Through 765kV or Extruded Insulation Rated 2.5kV Through 500kV Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-09-10 26 12 19 - 4 386-06 . Standard for Separable Insu

22、lated Connector Systems for Power Distribution Systems Above 600V 592-96 . Standard for Exposed Semiconducting Shields on High Voltage Cable Joints and Separable Insulated Connectors F. National Electrical Manufacturers Association (NEMA): C57.12.26-87 . Pad-Mounted, Compartmental-Type, Self-Cooled,

23、 Three-Phase Distribution Transformers for Use with Separable Insulated High-Voltage Connectors, High-Voltage, 34500 Grd Y/19920 Volts and Below; 2500 kVA and Smaller LA1-92 . Surge Arresters TP1-02 . Guide for Determining Energy Efficiency for Distribution Transformers TR1-00 . Transformers, Regula

24、tors, and Reactors G. National Fire Protection Association (NFPA): 70-08 National Electrical Code (NEC) H. Underwriters Laboratories Inc. (UL): 467-07 . Grounding and Bonding Equipment PART 2 - PRODUCTS 2.1 EQUIPMENT, GENERAL A. Equipment shall be in accordance with ANSI, ASTM, IEEE, NEMA, NFPA, UL,

25、 as shown on the drawings, and as specified herein. The transformer shall be assembled as an integral unit by a single manufacturer. B. Ratings shall not be less than shown on the drawings. C. Provide transformers designed to withstand the mechanical stresses caused by rough handling during shipment

26、 in addition to the electrical and mechanical stresses that may occur during operation. D. Completely fabricate transformers at the factory so that only the external cable connections are required at the job site. E. Thoroughly clean, phosphatize, and finish all the metal surfaces at the factory wit

27、h a rust-resistant primer and dark green enamel finish coat, except where a different color is specified in Section 09 06 00, SCHEDULE FOR FINISHES. All surfaces of the unit that will be in contact with the concrete pad shall be treated with corrosion-resistant compounds and epoxy resin or a rubberi

28、zed sealing compound. 2.2 COMPARTMENTS A. Construction: 1. Enclosures shall be in accordance with ANSI C57.12.28 /or ANSI C57.12.29 if installed in coastal environments/. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-09-10 26 12 19 - 5 2. The mediu

29、m- and low-voltage compartments shall be separated with a steel barrier that extends the full height and depth of the compartments. 3. The compartments shall be constructed of sheet steel (gauge to meet ANSI requirements) with bracing, reinforcing gussets, and jig-welding to ensure rectangular rigid

30、ity. 4. Use cadmium or zinc plated bolts, nuts, and washers. 5. Sufficient space shall be provided for equipment, cabling, and terminations within the compartments. 6. Affix transformer nameplate permanently within the low-voltage compartment. Voltage and kVA rating, connection configuration, impeda

31、nce, date of manufacture, and serial number shall be shown on the nameplate. B. Doors: 1. Provide a separate door for each compartment with provisions for a single padlock to secure all doors. Provide each compartment door with open-position doorstops and corrosion-resistant tamperproof hinges welde

32、d in place. The medium-voltage compartment door shall be mechanically prevented from opening unless the low-voltage compartment door is open. 2. The secondary compartment door shall have a one-piece steel handle and incorporate three-point locking mechanisms. SPEC WRITER NOTE: Include the following

33、paragraph for projects containing five or more transformers. /3. Provide a 2 in 50 mm size padlock for each assembly, as approved by the /Resident Engineer/COTR/. Padlocks shall be keyed to the /Resident Engineers/COTRs/ established key set. Firmly attach the padlock to the door assembly by a chain.

34、 / 2.3 BIL RATING SPEC WRITER NOTE: Edit the paragraphs below to conform to project requirements. /A. 5 kV class equipment shall have a minimum 60 kV BIL rating./ /B. 15 kV class equipment shall have a minimum 95 kV BIL rating./ /C. 25 kV class equipment shall have a minimum 125 kV BIL rating./ /D.

35、35 kV class equipment shall have a minimum 150 kV BIL rating./ 2.4 TRANSFORMER FUSE ASSEMBLY The primary fuse assembly shall be load-break combination fuse and dry-well fuse holder rated for system voltage, rated for 10 load makes and 10 load breaks, with rated 200 amp load current at 75% power fact

36、or, Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-09-10 26 12 19 - 6 10,000 symmetrical A close-in on fault duty, and 95 kV BIL. The entire fuse assembly shall be removable through the use of hot stick. 1. The fuses shall be concealed, hot stick re

37、movable, 50,000 A symmetrical interrupting, non-expulsion, current-limiting primary distribution type, of the size and voltage class as shown on the drawings. The fuses shall operate within the fuse holder as a unit disconnecting means. Fuses shall be in accordance with ANSI C37.47. 2. Transformers

38、shall not have internal “weak link“ fuses that require transformer tank cover removal for replacement. 3. For units above 500 kVA using fusing above the 50 A 15 kV and 100 A 5 kV application, a clip-mounted arrangement of the current limiting fuses (i.e., live-front configuration) is required. SPEC

39、WRITER NOTE: Select the appropriate paragraph below. 2.5 PRIMARY CONNECTIONS /A. Primary connections shall be live-front bushings with NEMA spades or eyebolt terminals suitable for cable sizes shown on the drawings./ /A. Primary connections shall be /200 A dead-front load break/ /600 A dead break/ w

40、ells and inserts for cable sizes shown on the drawings./ /B. Surge Arresters: Distribution class, one for each primary phase, complying with IEEE C62.11 and NEMA LA 1, supported from tank wall./ SPEC WRITER NOTE: Select the appropriate paragraph below, for the type of switch (radial or loop feed) an

41、d show on the drawings. CAUTION: A/E shall exercise care to limit loop circuits to 200 A to stay within equipment and termination capacity. 2.6 MEDIUM-VOLTAGE SWITCH /A. The transformer primary disconnect switch for radial feeds shall be an oil-immersed, internal, gang-operated, load-interrupter typ

42、e, rated 200 A, with a close-in on fault duty of 5,000 A symmetrical at voltage as shown on the drawings. The switch is to be a two-position, on-off, manual switch located in the medium-voltage compartment and hot-stick-operated. /1. Continuous current 200 A. A built-in switch with momentary current

43、 10,000 A symmetrical (2 seconds). Make and latch 6,000 A symmetrical./ /1. Continuous current 300 A. A separate switch in a free-standing weatherproof enclosure, pad-mounted beside the transformer, with momentary current 10,000 A symmetrical (2 seconds). Make and latch 10,000 A symmetrical./ Provid

44、ed by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-09-10 26 12 19 - 7 /1. Continuous current 600 A. A separate switch in a free-standing weatherproof enclosure, pad-mounted beside the transformer, with momentary current 10,000 A symmetrical (2 seconds). 10,00

45、0 A symmetrical (10 cycles). Make and latch 10,000 A symmetrical./ /B. Where a loop-feed operation (sectionalizing switch) is shown on the drawings, provide a four-position configuration arrangement, oil-immersed, gang-operated, rotary, loadbreak switch. The switch mechanism shall be spring-loaded a

46、nd the operation shall be independent of operator speed. The switch shall have the following ratings: 1. Continuous current 200 A. A built-in switch with maximum phase-to-phase voltage 35 kV, maximum phase-to-ground voltage 21.1 kV. Momentary 10,000 A for 10 cycles symmetrical./ SPEC WRITER NOTE: Se

47、lect the appropriate paragraph below. 2.7 MEDIUM-VOLTAGE TERMINATIONS /A. Terminate the medium voltage cables in the primary compartment with loadbreak premolded rubber elbow connectors, suitable for submersible applications. Elbow connectors shall have a minimum of 0.125 in 3 mm semi-conductive shi

48、eld material covering the housing. The separable connector system shall include the loadbreak elbow, the bushing insert, and the bushing well. Separable connectors shall comply with the requirements of IEEE 386, and shall be interchangeable between suppliers. Loadbreak elbow and bushing insert shall

49、 be from the same manufacturer. Allow sufficient slack in medium-voltage cable, ground, and drain wires to permit elbow connectors to be moved to their respective parking stands. Elbow connectors shall be rated as follows: 1. Voltage: /5kV/ /15kV/ phase-to-phase. 2. Continuous current: 200 A RMS./ /A. Terminate the medium-voltage cables in the medium-vo