REQUEST FOR PROPOSAL 18/24/30 MVA 138 kv to kv 3φ Power Transformers with LTC WEATHERFORD MUNICIPAL UTILITY SYSTEM

Transcription

1 REQUEST FOR PROPOSAL 18/24/30 MVA 138 kv to kv 3φ Power Transformers with LTC WEATHERFORD MUNICIPAL UTILITY SYSTEM SECTION I - SCOPE A. The Weatherford Municipal Utility System invites qualified and responsible applicants to submit a written proposal for the furnishing of three 18/24/30 MVA 138 kv to kv three phase substation power transformers with on-load tap changers designed and equipped per the attached technical specifications. B. It is the intent of this request to have the successful applicant enter into an agreement to furnish, ship, unload, install, and assemble each of the power transformers to one of the substations owned by the Weatherford Municipal Utility System, Weatherford TX, C. The first of the transformers is to be delivered mid-march, The timing of the remaining transformer deliveries is to be the subject of discussion between the Utility and the Applicant, but is to be completed no later than the fall of SECTION II - DEFINITIONS OF TERMS The following terms as used throughout this document and the attachments are defined as follows: A. Utility - The Weatherford Municipal Utility System, a public utility enterprise, wholly-owned by the City of Weatherford, Texas. B. Department The Electric Department, that portion of the Weatherford Municipal Utility System which owns and maintains the electric distribution system and substations. C. Director - The Director of the Weatherford Municipal Utility System and/or his/her designated representatives and/or agents. D. Applicant - Is interchangeable with and synonymous with the terms "BIDDER", "INSTALLER", "PROVIDER", each term of which is used to mean the person(s) who are submitting a written proposal to provide the specified services. E. R.F.P. - A "Request for Proposal" which details the services required by the City and the respective terms and conditions. A. Proposal - A formal written document and any supporting information submitted by the "APPLICANT" offering to furnish the equipment and provide the required services. 1

2 SECTION III - APPLICATION AND AWARD A. The "APPLICANT" shall pick up a Request for Proposal and/or detailed specification from the following location: Finance Department 303 Palo Pinto Weatherford, Texas Telephone No.: B. The applicant's completed "Proposal" and all required forms and supporting documents must be submitted on or before 2:00 pm, Tuesday August 18 th, The completed proposal shall be submitted to: Finance Department 303 Palo Pinto Weatherford, Texas Telephone No.: All RFP s will be publicly opened and respondent s names read aloud at 2:00 pm, Tuesday August 18 th, 2015, at City Hall Council Chambers, 303 Palo Pinto for the Substation Power Transformers Proposals. 2. All applications must be submitted in a sealed envelope clearly marked with the words PROPOSAL ; SUBSTATION POWER TRANSFORMERS. 3. Any proposals received after 2:00 pm, Tuesday August 18 th, 2015 will be considered late and non-conforming and returned to the applicant unopened. C. The Utility reserves the right to reject any and/or all proposals and/or any portion of a single proposal with or without cause. D. The Director will evaluate the conforming proposals for compliance with the terms and conditions. The Utility will approve the purchase of at least three identical transformers subject to the terms and conditions listed herein. E. The service agreement shall be awarded on a total bid basis for a single vendor, at the best value to the Utility, to provide Substation Power Transformers at its various sites. F. Upon completion of the approval process and approval of the agreement terms and conditions by the City of Weatherford Legal Department, the agreement will be signed by the successful applicant and the Utility. SECTION IV - APPLICATIONS AND QUALIFICATIONS 2

3 Each applicant which submits a written proposal must meet the minimum requirements as detailed in the RFP and shall include in his or her proposal the following documents; which will be used as the evaluation criteria in selecting the most qualified applicant(s): A. A complete resume including experience as it relates to this service with reference names and phone numbers. B. A complete technical description of the proposed substation power transformers. C. A statement outlining the assumptions and criteria used to design the proposed substation power transformers to be supplied to the Utility. D. A statement outlining the shipping, erection, assembly, filling, and testing of the transformer to be provided under contract. E. A statement of the proposed pricing structure for the provision of these services. F. Before submitting proposals, each bidder will be held responsible for having examined the Utility substation environments and satisfied itself as to the existing conditions under which he or she will be obligated to deliver, unload, assemble, and fill the transformer that will in any manner affect his or her services under the agreement. No allowances shall be made in this connection on behalf of the bidder for any error or negligence on his or her part. G. A completed copy of the attached Conflict of Interest form. SECTION V - GENERAL GUIDELINES The successful Provider will be required to enter into a written agreement with the Utility incorporating the proposal and this agreement. SECTION VI - SPECIFICATIONS The attached TECHNICAL SPECIFICATION FOR A 138/13.09KV, 18/24/30 MVA THREE PHASE POWER TRANSFORMER shall be incorporated by reference. 3

4 In WITNESS WHEREOF, the parties have caused this AGREEMENT to be duly executed, in multiple counterparts, intending to be bound thereby on this the day of,. WEATHERFORD MUNICIPAL UTILTITY SYSTEM Printed Name: Title: Signature: Date: SUBSTATION POWER TRANSFORMER PROVIDER Company: Printed Name: Title: Signature: Date: 4

5 WEATHERFORD MUNICIPAL UTILITY SYSTEM WEATHERFORD, TEXAS TECHNICAL SPECIFICATION FOR A 138/13.09KV, 18/24/30 MVA THREE PHASE POWER TRANSFORMER 1 of 36

6 TABLE OF CONTENTS- 1.0 SCOPE AND CLASSIFICATION SCOPE CLASSIFICATION APPLICABLE STANDARDS PRIORITY OF STANDARDS REGULATIONS FUNCTIONAL AND SUPPLIER REQUIREMENTS FUNCTIONAL REQUIREMENTS SUPPLIER REQUIREMENTS PERFORMANCE REQUIREMENTS RATINGS LOADING IMPEDANCE LOSSES SHORT CIRCUIT REQUIREMENTS AUDIBLE SOUND LEVEL LIQUID LEVEL ACCESSORIES AND ADDITIONAL REQUIREMENTS GENERAL MATERIAL BUSHINGS NAMEPLATE REQUIREMENTS CURRENT TRANSFORMERS SURGE ARRESTERS DE-ENERGIZED TAP CHANGER ON LOAD TAP CHANGER (LTC) INDICATING DEVICES COOLING EQUIPMENT OIL PRESERVATION SYSTEM CONTROL CABINETS AUXILIARY AND CONTROL POWER GROUNDING HANDLING VACUUM FILLING PAINT REQUIREMENTS INSULATING OIL INSPECTION AND TEST REQUIREMENTS OBSERVATION RIGHTS ROUTINE TESTS ADDITIONAL TESTS TEST REPORTS OTHER REQUIREMENTS DRAWINGS DESIGN REVIEW SHIPPING AND RECEIVING INSTALLATION WARRANTY MATERIAL SAFETY DATA SHEETS AND WASTE REDUCTION NOTIFICATION of 36

7 7.7 SERVICE BULLETINS LOSS SUBMITTAL REQUIREMENTS FALL PROTECTION of 36

8 1.0 SCOPE AND CLASSIFICATION 1.1 Scope This specification sets forth the minimum requirements for operating characteristics and safety features of a 138/13.09kV power transformer. 1.2 Classification The transformer shall be 18/24/30 MVA three phase, 138 kv delta kV wye, 65 C temperature rise, with an on load tap changer (LTC) The transformer will be installed at an altitude less than 3300 feet and subjected to an annual ambient temperature variance of -30 C to +45 C The transformer shall be designed for continuous operation at rated capacity at the specified altitude and ambient temperature range The transformer shall be capable of cold starting in a -30 Deg C ambient with the core and coil also at -30 Deg C. 2.0 APPLICABLE STANDARDS 2.1 Priority of Standards 2.2 Regulations Equipment supplied in accordance with this specification shall comply with applicable provisions of the latest NEMA, IEEE, ANSI/IEEE, ASTM, NESC, NEC, and ANSI standards relating to power transformers. In case of conflict between any of the standards mentioned in this specification and the contents of this document, the Weatherford Municipal Utility System specification shall govern The manufacturer shall inform WEATHERFORD MUNICIPAL UTILITY SYSTEM of all instances where there are conflicts between WEATHERFORD MUNICIPAL UTILITY SYSTEM specifications and the applicable standards The manufacturer, joint venture partners, and all sub-contractors shall comply with the United States of America Federal Acquisition Regulations when purchasing material for use in our transformers. 3.0 FUNCTIONAL AND SUPPLIER REQUIREMENTS 3.1 Functional Requirements The transformer will be used in an electric utility distribution substation to feed 12.47kV, 3 phase, 4 wire, grounded wye, with solidly grounded neutral circuits from the bus from separately furnished outdoor circuit breakers. The transformer will be used in a step-down application from the 138kV transmission system to the kv distribution system. 3.2 Supplier Requirements To preclude difficulties with overseas shipping and with WEATHERFORD MUNICIPAL UTILITY SYSTEM personnel access to the factory and to the design engineering team, the engineering and manufacturing location shall be restricted to North America. 4 of 36

9 3.2.2 The manufacturer shall be able to demonstrate no less than ten (10) years experience successfully building and testing power transformers of the size, complexity, and quality outlined in this specification The manufacturer shall be prepared to openly discuss with the WEATHERFORD MUNICIPAL UTILITY SYSTEM design consultant the manufacturers test floor failures and remedies over previous ten (10) year period The manufacturer shall be able to provide to WEATHERFORD MUNICIPAL UTILITY SYSTEM a list of installed transformers in the region which may be readily inspected by WEATHERFORD MUNICIPAL UTILITY SYSTEM personnel, and appropriate contacts within the Utility owning the installed transformers The manufacturer shall own or have an active alliance with a qualified transformer repair facility within the continental United States trained and equipped to repair the transformer outlined within this specification. 4.0 PERFORMANCE REQUIREMENTS 4.1 Ratings Frequency 60 Hz Phase Class ONAN/ONAF/ONAF Voltage High (HV) 138,000 (± 5%, DETC) Volts Delta Low (LV) 13,090 (± 10%, LTC) Volts Grounded Wye Capacity (at all LTC tap positions) Self-Cooled Forced-cooled Forced-cooled BIL HV LV Neutral 18 MVA 24 MVA 30 MVA 550kV 110kV 110kV Temperature Rises 4.2 Loading Maximum Average Winding Rise Maximum Hot Spot Rise (Windings and Leads) Maximum Top Oil Rise 65 C 80 C 65 C The continuous loading shall be as follows: Duty Terminal MVA Winding Temp. Rise by Resistance Continuous HV 18/24/30 65 C Continuous LV 18/24/30 65 C The transformer and all auxiliaries shall be capable of carrying overloads in accordance with ANSI/IEEE and this specification. The manufacturer shall demonstrate that all auxiliaries have adequate overload capability. 5 of 36

10 4.3 Impedance 138 /13.09 KV 18/24/30 MVA TRANSFORMER The transformer and all auxiliaries shall be additionally capable of carrying 125% of the top nameplate rating for a period of 12 continuous hours. This 12-hour emergency loading period shall commence after the transformer has been fully loaded for 6 hours, and the top oil temperature has stabilized at 95 C, which assumes a 30 C ambient temperature. During the 12 hour emergency loading period the ambient temperature shall be 40 C, the maximum top oil temperature shall be limited to 110 C, the maximum hot spot temperature shall be limited to 135 C, and the loss-of-life shall be limited to 0.1%. The PROPOSAL shall provide ultimate overload temperatures and loss of life calculations The neutral lead conductor and the neutral bushing shall be capable of carrying full load current. The neutral lead conductor and the neutral bushing shall also be capable of carrying all overloads in accordance with ANSI/IEEE The transformer shall be designed and manufactured to allow continuous operation of all windings at 110% voltage at no-load and at 105% output voltage at full load and 0.8 power factor without gassing. The positive sequence impedance of the transformer shall be 9.92% at the self cooled, base rated MVA, with the DETC and the LTC on the neutral tap positions. The tolerance on impedance shall be in accordance with Section 9.2 of ANSI/IEEE. 4.4 Losses The transformer losses will be used in the evaluation of the Proposals. No-load and load loss values at the 1 raise LTC position at the self cooled rating shall be supplied with the PROPOSAL and will be used in the evaluation. If the transformer has a LTC, which uses variable volts per turn design, the no-load losses shall be guaranteed on the LTC position having the highest no-load losses. The manufacturer shall state in the PROPOSAL the DETC and LTC positions with the highest no-load losses as the guaranteed losses in the case of variable volts per turn design. The manufacturer shall also submit with the PROPOSAL the auxiliary load at the maximum forced cooled rating for use in the evaluation. The following life cycle costs will be used for design purposes and will be evaluated separately when assessing any loss penalties. Cost of no-load losses Cost of load losses Cost of auxiliary losses $ 10,820/kW $ 3,160/kW $ 3,160/kW The manufacturer shall submit with the PROPOSAL the percentage maximum total measurement error for the no-load loss measurement and the load loss measurement systems. The errors must contain all components of the error including probable calibration errors and other uncertainties in the measurement system. Certified data for the loss measurement errors shall be submitted with the PROPOSAL. The data shall be traceable to the United States National Institute of Standards and Technology or other equivalent standardization organization. Equivalency will be determined by WEATHERFORD MUNICIPAL UTILITY SYSTEM using supporting documentation provided by the manufacturer as part of the PROPOSAL. A system check to insure that all errors have been properly applied may be required. Failure to submit a loss measurement system error or the submission of an error that is obviously erroneous will result in the rejection of the PROPOSAL. The maximum loss measurement error that is acceptable is ± three (3) percent as per ANSI/IEEE and NIST. Loss measurement errors greater than ± three (3) percent will result in the rejection of the manufacturer s PROPOSAL. 6 of 36

11 4.4.3 The no-load losses and excitation current at room temperature after impulse tests shall be used as the guaranteed values and shall not deviate from the no-load losses and excitation current values measured before impulse tests by more than five (5) percent. If the difference between the before and after values are greater than five (5) percent, WEATHERFORD MUNICIPAL UTILITY SYSTEM shall be contacted and a course of action determined. It is expected that the manufacturer shall determine the cause and correct any problems that result in deviations in no-load losses and excitation current that are greater than five (5) percent. WEATHERFORD MUNICIPAL UTILITY SYSTEM reserves the right to reject the transformer if satisfactory explanations or corrections are not made A transformer which, after factory testing, has actual losses exceeding the guaranteed losses, as stated in the seller s PROPOSAL, shall have its selling price reduced. The amount of reduction will be calculated by determining the actual losses, in kw, above and beyond the proposed guaranteed kw losses, multiplied by the evaluated cost per kw. Measured loss values shall be considered separately when assessing loss penalties (If a loss item is less than the guarantee it cannot be used to offset another loss component that is higher than the guarantee). 4.5 Short Circuit Requirements The transformer shall be capable of withstanding the mechanical and thermal stresses produced by external short circuits under the conditions specified in ANSI/IEEE except allowances for system impedance are not allowed. The available short circuit currents shall be calculated based on infinite bus source feeding the transformer. In addition, the source voltage shall be 110% of nominal at nominal DETC tap rating The manufacturer shall investigate the different fault conditions (three-phase fault, single line to ground fault, etc.) for the various combinations of tap positions and design for the highest stress conditions Where applicable, transformer windings shall be designed for free buckling and forces shall not exceed 65% of the 0.2% yield stress of the conductor. The calculated tensile stresses in the conductor shall be limited to 80% of the 0.2% yield stress of the copper The manufacturer is expected to have adequate model and full size transformer test data on which to base the acceptance criteria for stresses The manufacturer shall provide to WEATHERFORD MUNICIPAL UTILITY SYSTEM engineer a copy of all criteria and calculations used to calculate the fault stresses. WEATHERFORD MUNICIPAL UTILITY SYSTEM prefers that this information be provided in an electronic format that our standard programs can read The mechanical stress in the tie plates shall be limited to 65% of the elastic limit for the steel during short circuit events as well as for stresses incurred during lifting. 4.6 Audible Sound Level The average sound level shall not exceed 68 db for the ONAN rating and shall not exceed 70 db for the maximum forced cooled rating as measured by the procedures outlined in ANSI/IEEE at the maximum sound level position. 4.7 Liquid Level The main and LTC compartments shall be designed so that a low-level liquid alarm will not be activated when the ambient temperature reaches a low of -30 degrees Celsius with no load connected to the LV bushings The main and LTC compartments shall be designed so that oil does not alarm or overflow the compartments when the ambient temperature reaches 45 degrees Celsius and the transformer is at 125% of maximum nameplate rating per ANSI standards. 7 of 36

12 5.0 ACCESSORIES AND ADDITIONAL REQUIREMENTS 5.1 General Use 0,1,2,3, for phase designation in lieu of N, A, B, C. Associate phase 1 with H1, X1, Y1, etc All manhole covers and manholes shall be round, with minimum interior manhole diameter of 24 inches The tank cover shall be designed to prevent water from standing on the cover All nuts, bolts, and washers used on the transformer shall be non-rust stainless steel or WEATHERFORD MUNICIPAL UTILITY SYSTEM engineer approved equivalent. All fasteners shall be metallic or WEATHERFORD MUNICIPAL UTILITY SYSTEM engineer approved equivalent Split or star lock washers shall not be furnished as locking or clamping devices inside the tank. Double nutting, or other methods approved by WEATHERFORD MUNICIPAL UTILITY SYSTEM, shall be used for locking or clamping on the lead support framework All gaskets shall be in recessed, machined grooves. All gasket surfaces shall be made up by flanges that are raised at least ¾ inches above the cover All gasket materials shall be of the highest quality and specifically chosen for the application considering transport shock and vibration, temperature ranges in storage and in operation, sealed fluids, leakage rates, and ease of repair Tank shall be designed so that welds will not be located within 6 inches of the corners. All tank panel welds with oil on one side shall be welded on both sides. Welders shall be certified to AWS D The tank, including the cover and base, shall be designed such that, after installation, there will be no permanent deformation caused by shipping or handling The serial number and impedance of the transformer shall be permanently stenciled on the nameplate and provided on construction record drawings The maximum allowable burrs on the slit or cut edges of electrical steel used in the core shall not exceed 0.8 mils. Excessive edge or surface damage during manufacture may be the basis for the rejection of the core. Manufacturer shall have established processes to prevent rusting on core edges during the manufacturing process The core gaps shall not be greater than 1/16. Gaps greater than 1/16 must be justified to WEATHERFORD MUNICIPAL UTILITY SYSTEM as part of their proposal The core induction at 110% voltage at no-load and 105% output voltage at full load and 0.8 power factor excitation shall not exceed 1.93 Tesla The core cross-section shall approximate a circle All windings shall be circular, and shall be designed and constructed with full circumference clamping rings HV or LV windings shall be disc or helical only; layered HV or LV windings are not acceptable The use of internal varistors will not be allowed All wiring external to the control cabinets shall be run in rigid metallic galvanized conduit or WEATHERFORD MUNICIPAL UTILITY SYSTEM engineer approved equivalent. Other accessories, such as thermocouple cable, shall also be run in rigid metallic galvanized conduit or WEATHERFORD MUNICIPAL UTILITY SYSTEM engineer approved equivalent. Transformer design shall minimize the use of conduit. 8 of 36

13 Any conduit shall be rigidly mounted on standoffs (so it does not lay flat on the transformer tank or external braces) and shall be painted to match the transformer. Installation and orientation of Conduit LB s shall be such that the wire access covers are positioned for easy access, allowing them to be removed using a standard length screwdriver. Using the transformer braces or other built-in channel that is subjected to the transformer heat is not allowed The manufacturer shall provide the following spare components for each transformer purchased without additional cost to WEATHERFORD MUNICIPAL UTILITY SYSTEM: One (1) Complete itemized set of gaskets along with one extra set for LTC. These components shall be delivered with the transformer The manufacturer shall state the special tools that are required for the installation and maintenance of the transformer in the PROPOSAL. In addition, the manufacturer shall provide any special tools required for the installation and maintenance of the unit without additional cost to WEATHERFORD MUNICIPAL UTILITY SYSTEM Care shall be taken in the design and assembly of the transformers to reduce and to minimize vibration. The transformer shall be free from any undue or harmful vibration, which would be detrimental to the operation of the transformer, and any auxiliaries mounted on the tank or connected to the transformer Internal Lead Routing: The lead routing for the active part shall be neat and orderly. The leads shall be clamped in place to prevent movement during transportation and operation. The leads shall be supported from the active part support structure with pressboard clamps; i.e. plastic lead ties, string ties, or fabric tape ties are not acceptable. Bundles of leads shall be configured to allow free oil flow on lead surfaces The transformer is to be designed to withstand the following minimum shipping accelerations: 5g longitudinal, 3g vertical, and 1.5g transverse The support structure for the lead assemblies shall not be fastened to the upper or lower winding clamping rings The winding temperature shall determine the loading capacity of the transformer. The loading shall not be limited by any ancillary device such as leads, cables, switches, bushings, etc The lead exit temperatures shall be limited to 3 C higher than the winding hot spot temperature of the associated winding The insulation structure of the transformer is to be designed in consideration of lightning impulse voltages, switching surge voltages, applied test voltages, and induced test voltages (enhancement and one hour levels). These voltages shall be used to determine the electrical stresses in the oil gaps in the major insulation system. The manufacturer shall analyze the electrical stresses and the conversion from impulse voltages to the one minute 60 Hz voltage shall be with an impulse ratio of 2.5. The calculated stresses shall be compared with the Weidmann curve for Partial Discharge Inception for Degassed Oil. There shall be a minimum of 20% margin between the curve value and the calculated electrical stresses For disk type coils it is required that crossovers be located between key spacer columns The core shall be designed such that the core hot spot temperature is limited to 130 C with an ambient temperature of 30 C. The excitation conditions shall be the maximum of the 100% voltage with full load, 110% voltage at no-load, or 105% output voltage with full load and 0.8 power factor. 9 of 36

14 5.2 Material 138 /13.09 KV 18/24/30 MVA TRANSFORMER The minimum pressure on the windings at final pressing after vapor phase processing is 4 N/mm² All material used in the construction of the transformer shall be new The conductor for all current carrying parts, including windings and leads, shall be copper or silver bearing copper. Where conductors are spliced, all connections shall be inspected for quality prior to taping. Joints shall be made by mechanical crimping or by induction brazing only, soldering or torch brazing will not be accepted. No joints shall be permitted in draw leads inside bushings All material used, or proposed to be used, in the transformer shall be tested, and have passed the transformer oil compatibility test using the method outlined per ASTM or WEATHERFORD MUNICIPAL UTILITY SYSTEM engineer approved equivalent. The test reports shall be available upon request for WEATHERFORD MUNICIPAL UTILITY SYSTEM inspection at any time during the PROPOSAL or manufacturing process. Any material found by WEATHERFORD MUNICIPAL UTILITY SYSTEM inspector which has not had the oil compatibility test performed on it, or that the manufacturer cannot produce an oil compatibility test report for, shall be tested immediately at the manufacturer s expense. If the material fails the oil compatibility test, WEATHERFORD MUNICIPAL UTILITY SYSTEM will not accept the transformer until all non-compliant material is replaced All material used in the transformer shall be subject by the manufacturer to rigid quality assurance and control standards. The manufacturer shall have complete traceability on all material from receiving until final installation in the transformer. Material tracking and inspection reports shall be made available to WEATHERFORD MUNICIPAL UTILITY SYSTEM inspector upon request The manufacturer shall have conducted an initial vendor inspection and qualifying audit with ongoing spot checks on all material used in the transformer. Vendor inspection and audit reports shall be made available to WEATHERFORD MUNICIPAL UTILITY SYSTEM inspector upon request. Materials found by WEATHERFORD MUNICIPAL UTILITY SYSTEM inspector to have not been properly qualified for use by the manufacturer shall, as a general rule, be unacceptable for use in the transformer. The manufacturer, at the manufacturer s expense, shall make arrangements satisfactory to WEATHERFORD MUNICIPAL UTILITY SYSTEM, up to and including the replacement of the non-qualified material The cellulose insulation barriers and spacers shall be high-density material ( g/cc). Low-density pressboard is acceptable for formed insulation parts. The paper insulation for winding conductors shall be high density, thermally upgraded, and shall be Dennison 22HCC, Tullis-Russell Rotherm, or approved equal The winding conductor insulation shall be thermally stabilized. Insulation on all conductors used in the coil winding process shall be cellulose insulating paper. It shall be wound onto the conductor using a spinning process. The paper insulation shall be applied in single or multiple strands such that a minimum of 30% of the paper surfaces are overlapped to provide for a continuous insulating surface. Sufficient tension shall be maintained on the paper strands so as to prevent loose wraps. Paper taped conductor shall be supplied by Algonquin or approved equal. The performance of the paper shall meet the following criteria: The paper shall retain at least 50% of its original tensile strength after exposed to 110ºC for hours The paper shall have a degree of polymerization of at least 200 after hours at 110ºC. 10 of 36

15 5.3 Bushings 138 /13.09 KV 18/24/30 MVA TRANSFORMER The electrical steel for the core shall be state-of-the-art material, H1 laser scribed electrical steel supplied by AK Steel or approved equal Insulation for winding-to-bushing conductors and the leads to the DETC and LTC shall be thermally upgraded material All material shall be traceable to its point of origin All material shall have test reports to verify that the material conforms to the applicable standards. These reports shall be provided to WEATHERFORD MUNICIPAL UTILITY SYSTEM upon request The XV bushings shall be ABB cat. # 015W2000A or to WEATHERFORD MUNICIPAL UTILITY SYSTEM engineer approved equivalent The X0 bushing shall be ABB cat. # 015W2000A or to WEATHERFORD MUNICIPAL UTILITY SYSTEM engineer approved equivalent The HV bushings shall be ABB cat. # 138W0800AE or WEATHERFORD MUNICIPAL UTILITY SYSTEM engineer approved equivalent Bushings that are bottom connected, shall have a non-plated brass connector, and be designed for that application Request for variance approval shall be submitted to WEATHERFORD MUNICIPAL UTILITY SYSTEM Engineer at least three weeks prior to the start of design review Bushing color shall be ANSI #70 light gray The BIL ratings for the bushings shall be as follows: Terminals BIL Voltage Class HV 650kV 138kV XV 110kV 15kV The HV bushings shall be located in segment 3, the XV bushings shall be located in segment 1, and the X0 bushing shall line up with the other XV bushings adjacent to X1 bushing, per ANSI All bushings shall be supplied with stud to four-hole NEMA 4 X 4 pad connectors. The four-hole NEMA pad shall have machined milled surfaces on both sides to permit conductors to be attached to both sides. The connectors shall be suitable for connection to aluminum bus or jumpers and copper bus Minimum center to center spacing of the 138kV bushings shall be 84 inches Minimum center to center spacing of the 13.09kV bushings shall be 30 inches. 5.4 Nameplate Requirements The manufacturer shall supply all nameplates as specified in the ANSI/IEEE standards. All nameplates shall be made from non-rust stainless steel or aluminum with Mil Spec protective coating. The information contained on the nameplates shall be inscribed and painted black. All the information shall be in English and in standard non-metric units of measure The manufacturer shall indicate the total weight of cellulose insulation contained in the transformer on the main nameplate A nameplate for series transformer and/or reactor shall be supplied on the main tank nameplate when applicable. 11 of 36

16 5.5 Current Transformers 138 /13.09 KV 18/24/30 MVA TRANSFORMER Bushing current transformers for WEATHERFORD MUNICIPAL UTILITY SYSTEM use shall be provided. The manufacturer shall install bushing-type current transformers as indicated below Multi-ratio bushing current transformers shall conform to ANSI/IEEE. All current transformers shall be ANSI Class C400, with a minimum Thermal Rating Factor (RF) of 2.0, except for those CT s needed solely for hot-spot calculations or for LDC inputs which do not need to be C400. The following CT's shall be supplied, per phase: 5.6 Surge Arresters Terminal Number of CT's per phase CT ratio HV (H1, H2, H3) 2 400/5 multi-ratio with ANSI Standard taps XV (X1, X2, X3) /5 multi-ratio with ANSI Standard taps XV (X0) /5 multi-ratio with ANSI Standard taps All secondary leads of current transformers shall be brought to a common outlet housing near the cover and then to the weatherproof control cabinet. CT lead splicing is not allowed. At the control cabinet each lead shall be terminated on a terminal block with short circuiting provisions. Each multi-ratio current transformer shall terminate on a separate block At least two (2) circular manholes shall be provided in the cover of the main tank to allow the removal or addition of current transformers. Each manhole shall be a minimum of 24 in diameter The transformer shall be provided with metal oxide station class surge arresters. The HV arresters shall be ABB Cat # P120SA098A equipped with appropriate accessories. The XV arresters shall be ABB Cat # P010SA008A The manufacturer shall provide mounting for the arresters. The manufacturer shall minimize the distance between the surge arrester and the bushing. On the HV side, the arrestor s 4-hole pad shall be at the same elevation as the bushing s 4-hole pad Surge Arresters shall be grounded to a minimum 4/0 AWG stranded bare copper ring. The surge arrester grounding ring shall be bonded to ground pads at diagonal corners of the transformer. Surge arrester ring shall be arranged so that it does not present a tripping or falling hazard to personnel working on top of the transformer tank All surge arresters shall be manufactured and tested in accordance with ANSI/IEEE Each surge arrester shall be in line with its respective bushing. 5.7 De-energized Tap Changer The transformer shall be provided with full capacity high voltage de-energized taps of: 131,100V; 134,550V; 138,000V; 141,450V; 144,900V (HV) Operation of the de-energized tap changer from ground level is required. The deenergized tap changer position indicator shall be visible from ground level Provisions for padlocking shall be furnished for each de-energized tap position The de-energized tap changer shall be arranged to provide for inspection and maintenance without un-tanking The de-energized tap changer shall be designed, manufactured, and tested to require maintenance and moving of the tap changer to wipe the contacts at an interval of no less than five years. Maintenance intervals of less than five years are not acceptable. 12 of 36

17 5.7.6 The DETC shall be provided with silver plated contacts. There shall also be only one external operating mechanism for a three phase DETC. 5.8 On Load Tap Changer (LTC) The transformer shall be equipped with an automatic on load tap changer meeting the following requirements: The LTC equipment shall be a Reinhausen Type RMV-II tap changer The LTC and all associated windings shall be capable of operating at the maximum transformer rating (MVA) continuously The manufacturer shall provide a separate complete nameplate for the LTC The regulating winding shall be fully distributed The LTC shall be located in the low voltage winding Provisions shall be provided for 32 steps. All tap positions shall be full capacity. Each step will correspond to a change in voltage of 5/8 percent of center tap voltage (13.09kV) The transformer and the on load tap changer shall be designed to operate in a stepdown mode. The primary mode of operation of the LTC will be to keep the secondary voltage constant as the load varies on the kv system and as the voltage changes on the 138 kv system The load tap changer control cabinet shall be located so it can be accessible from ground level A table of voltages and currents for each LTC position at the 65 C maximum nameplate rating at all tap voltages shall be provided on the nameplate Provisions for manual switching of the on load tap changer shall be made in the control cabinet as follows: Local/Remote Switch A Local/Remote Control Switch shall be provided that can switch control of the LTC from the control cabinet (local) to WEATHERFORD MUNICIPAL UTILITY SYSTEM remote supervisory equipment (remote) Auto/Manual Switch An Auto/Manual Control Switch shall be provided that when the Local/Remote Switch is in Local can switch the LTC from Manual to Automatic mode Lower/Off/Raise Switch A Lower/Off/Raise Control Switch shall be provided that when the Local/Remote Switch is in Local and the Auto/Manual Switch is in Manual can raise and lower the LTC. This is in addition to the maintenance switch required under One spare contact for each position shall be provided for the Local/Remote Switch and Auto/Manual Switch. These contacts shall be wired to a terminal block While the Local/Remote Switch is in the remote position, provisions shall be made for the switching the on load tap changer control from auto to manual and from manual to auto upon operation of a Form C latching contacts from WEATHERFORD MUNICIPAL UTILITY SYSTEM remote supervisory equipment While the Local/Remote Switch is in the remote position, the transformer tap position may be changed upon receipt of a signal from WEATHERFORD MUNICIPAL UTILITY SYSTEM remote supervisory equipment. The manufacturer shall provide all the equipment in the transformer necessary to effect these operations. Every such signal shall result in one tap position change, regardless of signal duration Provisions shall be provided for status indication to WEATHERFORD MUNICIPAL UTILITY SYSTEM remote supervisory equipment when the LTC is in the automatic 13 of 36

18 mode. This status should occur regardless of the position of the Local/Remote Switch. This circuit can use an Auto control contact (closes when LTC is in automatic) from WEATHERFORD MUNICIPAL UTILITY SYSTEM remote supervisory equipment. WEATHERFORD MUNICIPAL UTILITY SYSTEM will provide a schematic diagram for this circuit The on load tap changer motor shall be mounted in the control cabinet and it shall be readily accessible with the transformer energized. The motor shall be equipped with overcurrent protection with a manual reset The manufacturer shall wire all equipment control wiring to a terminal strip in the control cabinet. WEATHERFORD MUNICIPAL UTILITY SYSTEM will connect wiring for Raise, Lower, Auto, and Manual to this terminal strip The manufacturer shall provide one (1) mechanical counter to count all LTC operations. The counter shall be easily readable from ground level The following electrical accessories shall be provided in the LTC control cabinet: one (1) Waukesha positive coefficient heater to prevent condensation (no equivalent accepted); one (1) 120 V, 100 W equivalent, mechanically protected fluorescent outdoor light equipped with an outdoor fixture and outdoor door-operated switch; and one (1) 120 V, 20 Amp, outlet equipped with a Ground Fault Interrupting Device (GFCI). Each accessory shall be supplied from a separately protected circuit A mechanical position indicator with maximum and minimum indicating hands shall be provided. The position indicator shall be visible through a window in the door of the LTC control cabinet and shall also be visible from the manual control panel. The manufacturer shall provide a push button to reset the maximum and minimum indicating hands. The push button shall be located in the main control cabinet The manufacturer shall supply one (1) static voltage regulating relay, SEL catalog number X114AXXXXXXX, to automatically control the operation of the LTC. Potential input and relay output test switches shall be provided, such that the customer can isolate the output contacts and test the device A neutral indicating contact shall be provided in the LTC mechanism, and wired to the voltage regulating relay to assist the control in keeping track of LTC position The LTC type and rating shall be selected for a minimum of 500,000 operations at full load before LTC contact maintenance is required. The LTC shall be designed to achieve the full 500,000 operations on any combination of adjacent taps The manufacturer shall provide verification with the PROPOSAL submittal that the selected LTC meets the requirements contained in this section. The verification shall include, but not be limited to, the minimum number of operations before the mechanism and contacts require maintenance and the calculations used to arrive at this number The manufacturer shall provide one (1) combination 1 drain and sampling valve located at the bottom of the LTC compartment. The sampling device shall be suitable for use with ¼ I.D. Tygon tube for taking oil samples The manufacturer shall provide electrically interlocked hand crank for manual operation of the LTC The manufacturer shall provide limit switches and mechanical stops to prevent overtravel of the drive mechanism, and the LTC motor drive mechanism shall not be capable of being stopped in any off tap position due to loss of control power, motor failure, or control problem The manufacturer shall provide one (1) rapid pressure rise sensing unit mounted on the LTC compartment. The unit shall be equipped with test plugs to simulate a rapid pressure rise so that the unit can be tested periodically. The rapid pressure rise sensing unit shall be a Qualitrol Series 910 Rapid Pressure Rise Relay, or other manufacturer 14 of 36

19 recommended relay with WEATHERFORD MUNICIPAL UTILITY SYSTEM Engineer approval. The rapid pressure rise relay shall have a form c contact, which will be used for tripping The manufacturer shall provide one (1) automatic pressure relief device, which can be reset manually, mounted on each LTC compartment. The alarm contactor for this device shall be routed to the main control cabinet. The automatic pressure relief device shall be a Qualitrol Series 208 Pressure Relief Device The manufacturer shall provide one (1) magnetic liquid level gauge for the LTC. The gauge shall include one form c contact for LTC tank, low liquid level alarm and another form c contact for LTC tank, low liquid level trip, to operate when a risk of a flash over can occur. These alarm and trip settings shall be set by the manufacturer. The liquid level gauge shall have a six inch diameter dial. The magnetic liquid level gauges shall be Qualitrol, or approved alternative, as agreed upon by WEATHERFORD MUNICIPAL UTILITY SYSTEM engineer. The gauge shall be marked as to its intent The manufacturer shall provide terminal board points for PT terminations in the LTC cabinet The manufacturer shall provide a ventilated weatherproof control cabinet with hinged doors equipped with wind latches. The doors shall provide access to the control devices and have provisions for padlocking. All cabinet and door hardware shall be non-rust stainless steel A line-drop compensator (LDC) current transformer shall be provided on the X1 bushing. This CT shall have an output of 5 amps. A 5 amp to 0.2 amp transformer (Beckwith M-0169A or approved equal) shall be used to convert the current to 0.2 amps for the voltage regulating relay If a series transformer or preventative autotransformer is used in the LTC circuit, the windings of these transformers shall be the same type as the main windings. The manufacturer shall use the same winding construction methods on all windings in the transformer including the series transformer All exposed rotating drive shafts and related components shall be protected from accidental contact with steel covers. The steel covers shall be of sufficient rigidity and supported to prevent deformation Jacks for connecting a meter to monitor sensing potential shall be provided near the voltage regulating relay LTC operation test switch and service light shall be provided near the voltage regulating relay LTC off step alarm normally open contact shall be provided. This contact should not close during normal operation of the LTC or for loss of AC All auxiliary transformers (preventive auto and series) shall be constructed to class 2 power transformer standards including circular core and coil design using all copper conductors LTC sensing voltage shall be 120V, 60 Hz AC The LTC breather desiccant system shall be a Waukesha maintenance-free system, and it must be accessible from ground level, no higher than four feet from the bottom of the transformer tank Lead connections to the LTC terminal board shall be fastened with two bolts per connection. All bolted electrical connections in the transformer are to be made with a minimum of two bolts. The bolt pattern shall be a NEMA 2-hole pattern A raise, off, lower spring return selector switch shall be mounted in the LTC motor housing near the on step position indicator. This switch shall bypass the LTC controls 15 of 36