CSA C301 2-2006 Three-phase submersible distribution transformers (Second Edition).pdf

1、C301.2-06(reaffirmed 2011)Three-phase submersible distribution transformersLegal Notice for StandardsCanadian Standards Association (CSA) standards are developed through a consensus standards development process approved by the Standards Council of Canada. This process brings together volunteers rep

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16、CSA Standards Update ServiceC301.2-06March 2006Title: Three-phase submersible distribution transformersPagination: 16 pages (vii preliminary and 9 text), each dated March 2006To register for e-mail notification about any updates to this publicationgo to www.ShopCSA.caclick on E-mail Services under M

17、Y ACCOUNTclick on CSA Standards Update ServiceThe List ID that you will need to register for updates to this publication is 2019185.If you require assistance, please e-mail techsupportcsa.ca or call 416-747-2233.Visit CSAs policy on privacy at www.csagroup.org/legal to find out how we protect your p

18、ersonal information.Published in March 2006 by Canadian Standards AssociationA not-for-profit private sector organization5060 Spectrum Way, Suite 100, Mississauga, Ontario, Canada L4W 5N61-800-463-6727 416-747-4044Visit our Online Store at www.ShopCSA.caC301.2-06Three-phase submersible distribution

19、transformersCSA StandardISBN 1-55436-168-0Technical Editor: John ONeill Canadian Standards Association 2006All rights reserved. No part of this publication may be reproduced in any form whatsoever without the prior permission of the publisher.March 2006 iiiContents Canadian Standards Association Thr

20、ee-phase submersible distribution transformersTechnical Committee on Distribution Transformers ivSubcommittee on Network and Submersible Distribution Transformers viPreface vii1Scope 12 Reference publications and definitions 12.1 Reference publications 12.2 Definitions 23 Electrical features 23.1 Ge

21、neral 23.2 Voltage designation 23.3 Voltage and basic impulse insulation levels (BIL) 34 Mechanical features 34.1 General 34.2 Dimensions 34.3 Sealed construction 34.4 Lifting lugs 44.5 Associated apparatus 45 Bushings, terminals, and grounding 45.1 Bushings and terminals 45.1.1 High-voltage bushing

22、s 45.1.2 Low-voltage bushings 55.2 Grounding 56 Finish 57Tests 68Marking 68.1 Nameplate and connection diagram 68.2 Terminal marking 69 Optional accessories and features 6Tables1 High-voltage electrical characteristics of transformers and assembled high-voltage load-break terminals 72 Preferred low-

23、voltage and required BIL ratings 83 Basic physical sizes 8Figure1 Typical cover layout showing the preferred locations of high-voltage and low-voltage bushings, high-voltage switch handles, and grounding terminals 9C301.2-06 Canadian Standards Associationiv March 2006Technical Committee on Distribut

24、ion TransformersF. Chan Utilicorp Networks Canada,Calgary, AlbertaRepresenting Canadian Electricity AssociationChairG. Morrissette VA TECH Transformateurs Ferranti-Packard Inc.,Trois-Rivires, QubecRepresenting Canadian Electricity AssociationVice-ChairA. Beattie Electric and Utilities Safety Associa

25、tion,Mississauga, OntarioM. Bell Hydro One Networks Inc.,Toronto, OntarioM. Culhane Cooper Power Systems Inc.,Waukesha, Wisconsin, USARepresenting NEMAAssociateR. de Lhorbe Schneider Canada Inc.,Mississauga, OntarioM. Fischer BC Hydro,Burnaby, British ColumbiaD. Galloway ABB Power T (b) provide an e

26、xplanation of circumstances surrounding the actual field condition; and(c) be phrased where possible to permit a specific “yes” or “no” answer.Committee interpretations are processed in accordance with the CSA Directives and guidelines governing standardization and are published in CSAs periodical I

27、nfo Update, which is available on the CSA Web site at www.csa.ca. Canadian Standards Association Three-phase submersible distribution transformersMarch 2006 1C301.2-06Three-phase submersible distribution transformers1Scope1.1This Standard covers the features of three-phase submersible transformers r

28、ated 75 to 3000 kV A.Note: For details not covered herein, reference should be made to CSA C2.1.1.2This Standard applies only to three-phase distribution transformer units intended for use in a ventilated vault or enclosure below grade level, with all terminations and accessories cover mounted, or n

29、early so, for operation above grade. It does not apply to(a) directly buried transformers in contact with the earth;(b) permanently submerged transformers; or(c) network-type transformers.1.3The equipment covered by this Standard is intended primarily for operation by electrical utilities on effecti

30、vely grounded underground distribution systems having high voltages, as shown in Table 1.Note: The operation of transformers complying with this Standard by other than an electric utility may be subject to additional requirements by the electrical inspection authority having jurisdiction.1.4The equi

31、pment covered by this Standard typically has two high-voltage bushings for each phase designed for circuit loop feed within the transformer tank. High-voltage switching and fuse protection normally connected between this internal loop feed element and the transformer high-voltage winding is not cove

32、red by this Standard and is specified by the purchaser.1.5In CSA Standards, “shall” is used to express a requirement, i.e., a provision that the user is obliged to satisfy in order to comply with the standard; “should” is used to express a recommendation or that which is advised but not required; “m

33、ay” is used to express an option or that which is permissible within the limits of the standard; and “can” is used to express possibility or capability. Notes accompanying clauses do not include requirements or alternative requirements; the purpose of a note accompanying a clause is to separate from

34、 the text explanatory or informative material. Notes to tables and figures are considered part of the table or figure and may be written as requirements. Annexes are designated normative (mandatory) or informative (non-mandatory) to define their application.2 Reference publications and definitions2.

35、1 Reference publicationsThis Standard refers to the following publications, and where such reference is made, it shall be to the edition listed below.C301.2-06 Canadian Standards Association2 March 2006CSA (Canadian Standards Association)C2.1-06Single-phase and three-phase liquid-filled distribution

36、 transformersANSI (American National Standards Institute)C57.12.28-2005Pad-Mounted Equipment Enclosure IntegrityIEEE (Institute of Electrical and Electronics Engineers)IEEE 386-1995Separable Insulated Connector Systems for Power Distribution Systems Above 600 V2.2 DefinitionsThe following definition

37、s apply in this Standard:Effectively grounded under line-to-ground fault conditions, the rms voltage-to-ground of the ungrounded phase cannot exceed 80% of the normal phase-to-phase voltage.Submersible transformer a transformer intended to operate for its design life installed in a vault and subject

38、ed to occasional total submersion and frequent wetting due to seepage of sewage and street or salt water.3 Electrical features3.1 General3.1.1Each transformer shall comply with the electrical requirements of CSA C2.1, except as specified in this Standard.3.1.2The rated kV A capacities at rated volta

39、ge shall be 75, 150, 225, 300, 500, 750, 1000, 1500, 2000, 2500, or 3000.3.1.3The kV A ratings are continuous and based on the winding temperature rise not exceeding 55 C average and 70 C in the hottest-spot. The temperature rise of the insulating oil shall not exceed 55 C, when measured near the to

40、p of the tank.3.1.4The transformers shall have a 65 C temperature rise insulation system.3.1.5The design of GrdY-GrdY connected units shall incorporate a four- or five-legged core or triplex construction.3.2 Voltage designationVoltage designations of the form E (e.g., 2400) indicate a winding perman

41、ently delta-connected. Canadian Standards Association Three-phase submersible distribution transformersMarch 2006 33.2.1Voltage designations of the form E1GrdY/E (e.g., 4160 GrdY/2400) indicates a winding having reduced insulation and permanently Y-connected with the transformer neutral grounded (E1

42、equals ).3.3 Voltage and basic impulse insulation levels (BIL)3.3.1Preferred high-voltage ratings, BIL requirements, and associated high-voltage terminal components are shown in Table 1.3.3.2Preferred low-voltage ratings and the required BIL rating for transformers are shown in Table 2.4 Mechanical

43、features4.1 General4.1.1All switch and fuse hardware, accessories, nameplates, and other fixtures exposed to the underground environment shall be corrosion-resistant.4.1.2The tank shall have a steel base welded thereto. The base shall support the tank at a minimum distance of 38 mm above the floor.4

44、.1.3When external cooling devices are used, fixed mechanical protection shall be provided at the base of the transformer to prevent damage to the cooling devices when lowering the transformer into the vault.4.2 Dimensions4.2.1The transformer assembly includes primary bushings, inserts, secondary ter

45、minals, and switch- or fuse-operating handle projections.4.2.2Unless otherwise specified by the purchaser, the maximum dimensions of the transformer assembly shall not exceed the values shown in Table 3.4.3 Sealed construction4.3.1The complete transformer assembly shall be of sealed construction and

46、 shall remain effectively sealed for a top oil temperature range of 40 C to 105 C. Welded covers shall be designed so that the grinding operations to remove the cover will not cause damage to the tank or cover, thereby preventing resealing. In addition, all covers shall be provided with a gasketed h

47、andhole a minimum of 200 mm in diameter. Bolted covers, if provided, shall be bonded to the tank wall with an internal flexible copper connection accessible from the handhole. Similarly, the handhole cover shall also be internally bonded to the tank cover.3EC301.2-06 Canadian Standards Association4

48、March 20064.3.2Provision shall be made on all units for the manual release of gas pressures by means of a valve or plug before servicing.4.3.3The transformer shall be of sufficient strength to withstand a minimum gauge pressure of 50 kPa without leakage or permanent distortion of the tank. Two 1/2 i

49、n (minimum) pipe plugs or fittings for filling, draining, and pressure testing shall be provided.4.4 Lifting lugsFour lifting lugs shall be provided diagonally opposite and near the top of the transformer tank. Separate lugs shall be provided for the core, coils, and also for the cover.4.5 Associated apparatus4.5.1Devices such as switches, adapters, separable insulated connectors, and replaceable fuses that are designed for operation after the transformer is in place shall be located so that they can be operated with live-line tools from above.4.5.2T