05-Inst._Trans._IDIQ_Specifications_Rev_1.docx

TRANSFORMERS

CT, CVT, VT, METERING UNITS AND SSVT

EQUIPMENT DESCRIPTION/SPECIFICATIONS

TABLE OF CONTENTS

1. Specifications For Current Transformers…………………………..……………………….1

2. Specifications For Coupling Capacitor Voltage Transformers..…...……….…………..…….…………………………………………..……….16

3. Specifications For Voltage Transformers………………………………...........…...……

4. Specifications For Metering Units ………………………………...........…...….…………..41

5. Specifications For Station Service Voltage Transformers………………………………...........…………………………………………….49

6. Seismic Qualification Requirements For Equipment..……................................….......................................................................…57

7. Electrical Drawings And Data To Be Furnished By The Contractor.…….............………………………………………………………………………..59

SPECIFICATIONS FOR CURRENT TRANSFORMERS

A. GENERAL:

The bid items 1 through 61 current transformers (CT’S) shall be in accordance with American National Standards Institute (ANSI), Institute of Electrical and Electronics Engineers, Inc. (IEEE), and National Electrical Manufacturers Association (NEMA) and specifically the latest versions of ANSI/IEEE C57.13 and ANSI/IEEE C57.13.6. Wound-type transformers shall be for base mounting. Wound-type CT’S (other than bar-type primary) shall be equipped with primary bypass devices for protecting the windings from high-voltage surges. Turns between any two taps shall be uniformly distributed along the entire core and arranged so that every 20 or 40 turns are fully distributed. CT’S shall be supplied with or without supporting structures, as required, when Western places the order for the equipment. Only new equipment of current and present day design shall be manufactured and furnished to Western under this contract.

B. MATERIAL AND SPECIFICATIONS:

The CT’S shall have the following ratings and features as shown in Table A-1 through Table A-9 below:

TABLE A-1

Item 2) 1000:5

Item 3) 200:5 Item 4) 1000:51)

Item 5) 200:5 Item 6) 1000:5

Item 7) 200:5 Item 8) 1000:5

Minimum accuracy range at 30ºC ambient temperature

Suitable for Operation with Ambient Temperature of:

Minimum Maximum 24 Hour Average

Minus 45ºC Plus 55ºC Plus 45ºC

Plus 45ºC

TABLE A-2

Item 10) 1000:5

Item 11) 500 or 600:5 Item 12) 1000:5 Item 13) 2000:5

Suitable for Operation with Ambient Temperature of:

Minimum

Plus 45ºC

TABLE A-3

Item 15) 1000:5 Item 16) 2000:5

500:5, 1000:5 or 2000:5

500:5, 1000:5 or 2000:5

Suitable for Operation with Ambient Temperature of:

Minimum

Plus 45ºC

Item 20) High Item 17) Low Item 19) Moderate Item 21) High

TABLE A-4

Item 23) 1000:5 Item 24) 2000:5

500:5, 1000:5 or 2000:5

500:5,

Suitable for Operation with Ambient Temperature of:

Minimum

Plus 45ºC

Item 28) High Item 25) Low Item 27) Moderate Item 29) High

TABLE A-5

Item 31) 1000:5 Item 32) 2000:5

500:5, 1000:5 or 2000:5

500:5,

Suitable for Operation with Ambient Temperature of:

Minimum

Plus 45ºC

Item 36) High Item 33) Low Item 35) Moderate Item 37) High

TABLE A-6

Item 39) 1000:5 Item 40) 2000:5

500:5, 1000:5 or 2000:5

500:5,

Suitable for Operation with Ambient Temperature of:

Minimum

Plus 45ºC

Item 44) High Item 41) Low Item 43) Moderate Item 45) High

TABLE A-7

Item 39) 1000:5 Item 40) 2000:5

500:5, 1000:5 or 2000:5

500:5,

Suitable for Operation with Ambient Temperature of:

Minimum

Plus 45ºC

Item 52) High Item 49) Low Item 51) Moderate Item 53) High

TABLE A-8

Item 39) 1000:5 Item 40) 2000:5

500:5, 1000:5 or 2000:5

500:5,

Suitable for Operation with Ambient Temperature of:

Minimum

Plus 45ºC

Item 60) High Item 57) Low Item 59) Moderate Item 61) High

1. THERMAL AND MECHANICAL RATINGS: The short time thermal and mechanical current ratings of wound-type current CT’S, in accordance with American National Standard, shall be not less than specified.

2. BUSHINGS: The bushings shall be porcelain type for oil-filled CT’S or may be either polymer, composite or of a silicon compound type if needed to pass the seismic requirements of IEEE 693, for the moderate or high seismic requirement ratings. Bushings shall be molded butyl rubber or molded epoxy resin, which are an integral part of the CT insulation system, for dry type CT’S that are furnished. All porcelains shall be wet process, homogeneous, and free from cavities or other flaws. The porcelain glazing shall be uniform in color and free from blisters, burns, and other defects. The color of the bushings shall be ANSI 70 gray color or may be a dark gray, (all-most black) color when epoxy or butyl rubber type of construction is furnished. Porcelain parts of each CT shall be made of one piece when rated below 1300-kV BIL.

When rated at 1300-kV and above, porcelain parts may be constructed of one piece or of multiple parts provided the multiple parts are assembled by one of the following methods:

(1) By flanged segments.

(2) By placing firing material in the joints between the segments and the entire porcelain part fired in one piece or:

(3) By securely holding the parts together with a clamping device through the centerline of the bushing. The joint must be at right angles to the longitudinal centerline of the bushing if this method is used.

Polymer, silicon, or composite type bushings shall consist of a core, housing, and end fittings as required. The outer material shall resist formation of electrical tracking on the surface of the insulating material, resist cracking, prevent hydrolysis (chemical process leading to electrical or mechanical degradation), have electrical and mechanical characteristics as required for the application, provide the necessary creep distance, shall have a life comparable to what a porcelain bushing provides, and withstand sunlight for the entire life of the equipment (resist ultra-violet radiation and pollution).

3. CONSTRUCTION: The CT’S shall be either dry type or oiled-filled type as stated and allowed in Tables A-1 through A-35 above. The CT’S shall be suitable for outdoor use, shall be hermetically sealed, and shall be completely factory sealed to prevent breathing and absorption of moisture. Dry type CT’S shall be constructed of a non-tracking insulation such as molded butyl rubber or molded epoxy resin.

Current transformers of the series-parallel primary type shall be designed and constructed so the series-parallel connections of the primary windings can be changed external to the case without opening or disturbing the main case.

Expansion tanks external to the main tanks will not be acceptable for oil-filled type CT’s. Also for oil-filled type CT’s, oil expansion and pressure relief shall be accomplished by the use of a stainless steel diaphragm assembly. The active part of the unit shall be located above the porcelain in aluminum head housing.

4. ACCESSORIES: Liquid-filled CT’S shall be provided with drain valves or plugs and with liquid-level gauges or indicators. Glass through which oil can be exposed to sunlight shall be capable of filtering out those sunrays that cause oil deterioration.

5. SERVICE CONDITIONS: The CT’S shall withstand the seismic, wind, unusual temperatures, and elevation conditions as specified. The CT’S shall withstand ASCE 7 wind load, with a minimum basic wind speed of 90 miles per hour and importance factor of 1.15. Wind and seismic loads are to be considered as not occurring simultaneously.

6. INSULATING LIQUID: The insulating liquid shall be the manufacturer’s standard product. The liquid shall not contain polychlorinated biphenyls (PCB). Each CT unit shall be permanently marked and certification furnished that states there is no PCB present in the insulating liquid when the unit is delivered to Western.

7. PRIMARY TERMINALS: For all 69-kV through 500-kV class oil-filled CT’S, including Items 1005B through 1011C, the primary line terminals shall be NEMA standard line 4-hole terminal pad conforming to the requirements of NEMA Standard CC 1. Also for Items 004G through 020F, grounding terminal shall be provided which is suitable for connecting from No. 2 AWG up to 500 KCMIL copper cable.

For all 15-kV class through 46-kV class dry-type CT’S, including Items 1001A through 1004A, provide primary terminals which are flat copper bars or provide tin-plated copper bars, which are suitable for either copper or aluminum connections. These terminals shall be equivalent to a 2-hole terminal as shown in NEMA CC 1, Figure 4-2, except the top hole is 9/16-inch diameter hole and the bottom hole is a slot with two 9/16 diameter holes (one hole at each end, up and down vertically, and a ¾-inch long slot in the middle). A ground terminal shall be provided on the base plate of all Item 1001A through 1004A CT’S which is equal to a 1/4-20 inch ground screw welded on the base plate or provide an alternate design to Western for consideration.

For Item No. 1005A, dry-type 69-kV CT’S, provide a NEMA 4-hole terminal pad as shown Standard CC 1 and provide a ground terminal clamp suitable for No. 2 AWG solid through 500 KCMIL cable.

8. POLARITY MARKERS: The polarity shall be shown on the equipment and applicable drawings for the primary and secondary circuits of the CT’S.

9. NAMEPLATE: The nameplate shall be furnished and made of stainless steel. The CT ratings and information prescribed by ANSI shall be included on the nameplate which is either etched or stamped into the metal to provide a permanent record which will not fade in the sunlight or fade due to aging.

10. SECONDARY TERMINAL BOX: Secondary circuits wiring shall be brought to a terminal box at the base of the CT’S where studs of a size of ¼-20 or of equal size or larger are provided so that the inter-connection of internal and external wiring of secondary circuits can be made. The terminal box shall be weatherproof design to keep moisture out and have a minimum of two knockouts for 1-inch NPT conduit hubs for CT Items 1001A through1004A. For CT Items 1005A through 1011C, furnish a minimum of three knockouts for 1 ½-inch NPT conduit hubs to allow installation of conduit to the terminal box. For all CT’S, a short-circuiting type terminal block or shorting terminal strips shall be provided which can short the CT secondary wiring inside the terminal box and prevent open circuits on the CT secondary wiring.

11. EXPLOSION-LIMITING CHARACTERISTICS: The oil-filled CT’S shall be of the type designed to minimize insulation breakdown and reduces the risk of porcelain explosion and fire. Pressure waves created by arching during failure shall be limited to the head of the transformer. The lower part of the transformer head shall be specially reinforced as required to limit transmission of mechanical forces to the porcelain insulator and the head shall be shielded with an appropriate housing to prevent horizontal projection of fragments during explosion.

In the event of catastrophic failure and explosion, such explosion shall be confined within a circle, the radius of which is not to exceed the height of the CT including its pedestal, for the maximum distance that any flying parts from the CT will be permitted to travel away from the CT, in a horizontal direction.

C. TESTS:

Each CT shall be tested in accordance with ANSI C57.13. Test instrument requirements shall be in accordance with ANSI Standard C39.1-1981 for 0.25 percent accuracy.

DIELECTRIC TEST.

(1) Applied potential at 50 Hz for 72 seconds or 60 Hz for 60 seconds.

(2) Induced potential.

MECHANICAL THERMAL RATINGS.

Mechanical short-circuit and thermal rating tests shall be performed in accordance with ANSI C57.13 if certifications confirming the requirements of the ratings are not available for CT’S of the same type and design required by these specifications. Verification of the thermal rating by calculation (in accordance with ANSI C57.13, paragraph 8.6.2) will be accepted in lieu of testing.

STANDARD APPLICATION DATA AT 60 HZ.

Except as modified herein, standard application data shall be furnished in accordance with ANSI C57.13, Section 6.10. Typical curves and data for ratio-correction-factor and phase-angle data and curves for the metering accuracy type CT’S will be acceptable if prepared from actual test performed on identical transformers. The manufacture shall certify the data and shall furnish it in both tabulated and curve form.

IMPULSE TESTS ON PRIMARY WINDINGS.

Each CT shall be tested in accordance with ANSI C57.13 paragraph 8.8.5. Certified impulse test reports will be accepted if they were prepared from actual tests performed on identical or pro-to-type transformers.

If impulse tests are required, a Western inspector may wish to witness the impulse tests.

D. PAINTING:

CT surfaces that are painted shall be painted by the manufacturer’s standard cleaning and shop-applied permanent paint system, with the color of paint to be ANSI 70 (gray). The paint system shall provide a minimum of 10 years corrosion–free protection.

E. SUPPORT STRUCTURES:

Any of the oil-filled type current transformers shown on the bid list may require an associated support structure. When Western requires the CT’S to be furnished with a support structure, one support structure shall be supplied with each CT and shall be made of galvanized steel. The support structures shall be hot-dip galvanized. The support structure shall have a minimum height of 96-inches (straight line distance) maintained between the bottom of the structure foundation to the bottom of the bushing. Western will provide the anchor bolts and all required embedded materials, based on the information provided by the Contractor, as shown on the drawings required by Section 7 entitled “Electrical Drawings and Data to Be Furnished by the Contractor.

Prior to galvanizing, grounding pads shall be provided 2 feet above the top of the base plate on all support structures. Two holes shall be drilled and tapped in the pads for 1/2-inch diameter bolts (13-UNC threading). The holes shall be spaced 1.75-inches center to center and vertically aligned in the center of the plates (NEMA spacing). Grounding pads shall be in accordance with NEMA CC1 and shall be made of stainless steel.

Refer to drawing 31 1075 "Substation Standards - Switch Operating and Equipment Platforms - Electrical Design and Details for support structure grounding pads details.

F. SEISMIC REQUIREMENTS:

Current transformers, rated 115-kV and above, purchased to be installed in moderate or high seismic areas, shall be designed and built to withstand the seismic requirements as specified in Section 6, entitled “Seismic Qualification Requirements for Equipment.

G. DRAWINGS AND DATA:

Furnish drawings and data for the CT’S as detailed in Section 7, entitled “Electrical Drawings and Data to Be Furnished by the Contractor.

SPECIFICATIONS FOR COUPLING CAPACITOR VOLTAGE TRANSFORMERS

Bid Items 62 through 117 coupling capacitor voltage transformers (CCVT’S) shall be in accordance with these specifications and American National Standards Institute (ANSI), Institute of Electrical and Electronics Engineers, Inc. (IEEE), and National Electrical Manufacturers Association (NEMA) Standard C93.1, where applicable. CCVT’S shall be for base mounting and shall be suitable for connection to high-voltage power circuits between line and ground. CCVT’S shall be supplied with or without supporting structures, as required, when Western places the order for the equipment. Only new equipment of current and present day design shall be manufactured and furnished to Western under this contract.

The CCVT’S shall have the following ratings and features as shown in Table B-1 through Table B-8 below:

TABLE B-1

Total Output Rating (minimum VA)

Item 63) 0.3% for M, W, X, Y, and Z

Suitable for Operation with Ambient Temperatures of:

Minimum

Plus 45ºC

TABLE B-2

Total Output Rating (minimum VA)

Item 65) .0.3% for M, W, X, Y, and Z

Relaying and Metering

Relaying and Metering

Suitable for Operation with Ambient Temperatures of:

Minimum

Plus 45ºC

Item 69) High Item 66) Low Item 68) Moderate Item 70) High

TABLE B-3

Total Output Rating

Item 72) .0.3% for M, W, X, Y, and Z

Relaying and Metering

Relaying and Metering

Suitable for Operation with Ambient Temperatures of:

Minimum

Plus 45ºC

Item 76) High Item 73) Low Item 75) Moderate Item 77) High

TABLE B-4

Total Output Rating

Item 79) .0.3% for M, W, X, Y, and Z

Relaying and Metering

Relaying and Metering

Suitable for Operation with Ambient Temperatures of:

Minimum

Plus 45ºC

Item 81) Moderate Item 83) High Item 80) Low Item 82) Moderate Item 84) High

TABLE B-5

Total Output Rating

Item 86) .0.3% for M, W, X, Y, and Z

Relaying and Metering

Relaying and Metering

Suitable for Operation with Ambient Temperatures of:

Minimum

Plus 45ºC

Item 88) Moderate Item 90) High Item 87) Low Item 89) Moderate Item 91) High

TABLE B-6

Total Output Rating (minimum VA)

Item 93) .0.3% for M, W, X, Y, and Z

Relaying and Metering

Relaying and Metering

Suitable for Operation with Ambient Temperatures of:

Minimum

Plus 45ºC

Item 95) Moderate Item 97) High Item 94) Low Item 96) Moderate Item 98) High

TABLE B-7

Total Output Rating

Item 100) .0.3% for M, W, X, Y, and Z

Relaying and Metering

Relaying and Metering

Suitable for Operation with Ambient Temperatures of:

Minimum

Plus 45ºC

Item 102) Moderate Item 104) High Item 101) Low Item 103) Moderate Item 105) High

TABLE B-8

* 600/1000:1 and 600/1000:1 (for 115-kV)

69,000 (for 115-kV)

Total Output Rating

Metering

Metering

Suitable for Operation with Ambient Temperatures of:

Minimum

Plus 45ºC

Item 110) High Item 107) Low Item 109) Moderate Item 111) High

TABLE B-9

* 800/1400:1 and 800/1400:1 (for 161-kV)

92,000 (for 161-kV)

Total Output Rating

Metering

Metering

Suitable for Operation with Ambient Temperatures of:

Minimum

Plus 45ºC

Item 116) High Item 113) Low Item 115) Moderate Item 117) High

1. BUSHINGS AND PORCELAINS: Bushings shall be made of porcelain material and the porcelains shall be wet process, homogeneous, and free from cavities or other flaws. As an alternative, bushings may be either polymer, composite or of a silicon compound type if needed to pass the seismic requirements of IEEE 693, for the moderate or high seismic requirement ratings. The glazing shall be uniform in color and free from blisters, burns, and other defects. The color of the porcelain shall be ANSI 70 gray. The porcelain parts of each CCVT bushing rated below 450-kV BIL shall be constructed of one piece.

For CCVT’S rated 450-kV BIL and above, the porcelain parts may be constructed of one piece or of multiple parts, provided the multiple parts are assembled by one of the following methods:

1. By flanged segments;

1. By placing firing material in the joints between the segments and the entire porcelain part fired in one piece; or;

1. By securely holding the parts together with a clamping device through the centerline of the bushing. The joint must be at right angles to the longitudinal centerline of the bushing if this method is used.

Polymer, silicon, or composite type bushings shall consist of a core, housing, and end fittings as required. The outer material shall resist formation of electrical tracking on the surface of the insulating material, resist cracking, prevent hydrolysis (chemical process leading to electrical or mechanical degradation), have electrical and mechanical characteristics as required for the application, provide the necessary creep distance, shall have a life comparable to what a porcelain bushing provides, and withstand sunlight for the entire life of the equipment (resist ultra-violet radiation and pollution).

2. CONSTRUCTION: The oil-filled part of oil-filled type CCVT’S shall be completely factory sealed to prevent breathing and absorption of moisture. The base housing shall be of weatherproof construction.

3. VOLTAGE TRANSFORMER: The voltage transformer for the CCVT’S shall consist of factory-adjusted elements that shall be mounted in the base housing of the CCVT’S. The burden watts, burden power factor, voltage ratio, and phase angle shall be factory adjusted.

4. SECONDARIES: Each CCVT shall have two electrically separate secondaries, each capable of supplying voltage at both marked ratios.

5. SAFETY DEVICES: Furnish each CCVT with the following safety devices:

Potential Grounding Switch: Provide a potential grounding switch between the capacitor divider intermediate voltage circuit and ground. The switch shall be operable by a hook stick from ground elevation without opening the base housing of the CCVT.

(1) Ground Terminal: Provide on the base of the CCVT’S a ground terminal, suitable for connecting from No. 2 AWG up to No. 500 KCMIL copper cable.

(2) Primary Line Terminals: Line terminals shall be NEMA standard line 4-hole terminal pad conforming to the requirements of NEMA Standard CC 1.

6. NAMEPLATE: The nameplate shall be furnished and made of stainless steel. The CCVT ratings and information prescribed by ANSI shall be included on the nameplate which is either etched or stamped into the metal to provide a permanent record which will not fade in the sunlight or fade due to aging.

7. SECONDARY TERMINAL BOX: Secondary circuits wiring shall be brought to a terminal box at the base of the CCVT’S where studs of a size of ¼-20 or of equal size or larger are provided so that the inter-connection of internal and external wiring of secondary circuits can be made. The terminal box shall be weatherproof design to keep moisture out and have a minimum of two 1 ½-inch NPT conduit hubs to allow installation of conduit to the terminal box.

8. INSULATING OIL: The insulation oil used in each CCVT shall be the manufacturer’s standard product. The insulating liquid shall not contain polychlorinated biphenyls (PCB). The units shall be permanently marked and certification furnished that states there is no PCB present when the equipment is delivered to Western.

9. SERVICE CONDITIONS: The CCVT’S shall withstand the seismic, wind, unusual temperatures, and elevation conditions as specified. The CCVT’S shall withstand ASCE 7 wind load, with a minimum basic wind speed of 90 miles per hour and importance factor of 1.15. Wind and seismic loads are to be considered as not occurring simultaneously.

C. TESTS:

Each CCVT shall be tested in accordance with ANSI C93.1. Test instrument requirements shall be in accordance with ANSI Standard C39.1 for 0.25 percent accuracy.

PRODUCTION TESTS: Perform the following production tests on each CCVT:

(1) Capacitance and dissipation factor.

(2) Dielectric.

(3) Accuracy.

(4) Polarity.

D. PAINTING:

CCVT surfaces that are painted shall be painted by the manufacturer’s standard cleaning and shop-applied permanent paint system, with the color of paint to be ANSI 70 (gray). The paint system shall provide a minimum of 10 years corrosion–free protection.

E. SUPPORT STRUCTURES:

Any of the CCVTs shown on the bid list may require an associated support structure. When Western requires the CCVTs to be furnished with a support structure, each CCVT shall be provided with a support structure which shall be made of galvanized steel. The support structures shall be hot-dip galvanized. The support structure shall have a minimum height of 96-inches (straight line distance) maintained between the bottom of the structure foundation to the bottom of the bushing, which satisfies the minimum clearance from live parts, in accordance with table 124-1 of the latest ANSI/IEEE Standard C2, titled “National Electrical Safety Code (NESC). Western will provide the anchor bolts and all required embedded materials, based on the information provided by the Contractor, as shown on the drawings required by Section 7 entitled “Electrical Drawings and Data to Be Furnished by the Contractor.

Prior to galvanizing, grounding pads shall be provided 2 feet above the top of the base plate on all support structures. Two holes shall be drilled and tapped in the pads for 1/2-inch diameter bolts (13-UNC threading). The holes shall be spaced 1.75-inches center to center and vertically aligned in the center of the plates (NEMA spacing). Grounding pads shall be in accordance with NEMA CC1 and shall be made of stainless steel.

Refer to drawing 31 1075 "Substation Standards - Switch Operating and Equipment Platforms - Electrical Design and Details for support structure grounding pads details.

F. SEISMIC REQUIREMENTS:

CCVTs, rated 115-kV and above, purchased to be installed in moderate or high seismic areas, shall be designed and built to withstand the seismic requirements as specified in Section 6, entitled “Seismic Qualification Requirements for Equipment.

Furnish drawings and data for the CCVTs as detailed in Section 7 entitled “Electrical Drawings and Data to Be Furnished by the Contractor.

SPECIFICATIONS FOR VOLTAGE TRANSFORMERS

Item 118 through Item 160 voltage transformers (VT’S) shall be in accordance with ANSI/IEEE C57.13, IEEE, and NEMA where applicable. The VT’S shall be wound type, suitable for base mounting and shall be suitable for connection to high-voltage power circuits between line and ground. VT’S and shall be supplied with or without supporting structures, as required, when Western places the order for the equipment. Only new equipment of current and present day design shall be manufactured and furnished to Western under this contract.

The VT’S shall have the following ratings and features as shown in Table C-1 through Table C-8 below:

TABLE C-1

Two-bushing Model, Dry Type Single-phase, outdoor, 60 Hz Two-bushing Model Dry Type Single-phase, outdoor, 60 Hz Single-bushing Model Dry Type

Item 119) 70:1 Item 120) 100:1 Item 121) 120:1 175/300:1 and 175/300:1

Item 119) 8400/14560 GY Item 120) 12000/20780 GY Item 121)14400/24940 GY

20125/34500 GY

Thermal Burden Rating (at 30˚C ambient) (minimum VA)

ANSI Accuracy Class Operation at Rated Voltage (Metering Accuracy)

Suitable for Operation with Ambient Temperatures of:

Minimum

Plus 45ºC

TABLE C-2

Two-bushing Model Dry Single-phase, outdoor, 60 Hz Two-bushing Model Dry

Thermal Burden Rating (at 30˚C ambient) (minimum VA)

ANSI Accuracy Class Operation at Rated Voltage (Metering Accuracy)

Suitable for Operation with Ambient Temperatures of:

Minimum

Plus 45ºC

TABLE C-3

Oil-Filled Type

Thermal Burden Rating (at 30˚C ambient)

ANSI Accuracy Class Operation at Rated Voltage (Metering Accuracy)

Suitable for Operation with Ambient Temperatures of:

Minimum

Plus 45ºC

Item 129) High Item 126) Low Item 128) Moderate Item 130) High

TABLE C-4

Oil-Filled Type

Thermal Burden Rating (at 30˚C ambient)

ANSI Accuracy Class

(Metering Accuracy)

Suitable for Operation with Ambient Temperatures of:

Minimum

Plus 45ºC

Item 135) High Item 134) Low Item 136) Moderate Item 138) High

TABLE C-5

Oil-Filled Type

Thermal Burden Rating (at 30˚C ambient)

ANSI Accuracy Class

(Metering Accuracy)

Suitable for Operation with Ambient Temperatures of:

Minimum

Plus 45ºC

Item 141) High Item 138) Low Item 140) Moderate Item 142) High

TABLE C-6

Oil-Filled Type

Thermal Burden Rating (at 30˚C ambient) (minimum VA)

ANSI Accuracy Class Operation at Rated Voltage (Metering Accuracy)

Suitable for Operation with Ambient Temperatures of:

Minimum

Plus 45ºC

Item 147) High Item 144) Low Item 146) Moderate Item 148) High

TABLE C-7

Oil-Filled Type

Thermal Burden Rating (at 30˚C ambient)

ANSI Accuracy Class

(Metering Accuracy)

Suitable for Operation with Ambient Temperatures of:

Minimum

Plus 45ºC

Item 153) High Item 150) Low Item 152) Moderate Item 154) High

TABLE C-8

Oil-Filled Type

Thermal Burden Rating (at 30˚C ambient)

ANSI Accuracy Class

(Metering Accuracy)

Suitable for Operation with Ambient Temperatures of:

Minimum

Plus 45ºC

Item 159) High Item 156) Low Item 158) Moderate Item 160) High

1. BUSHINGS AND PORCELAINS: The bushings shall be porcelain and all porcelains shall be wet process, homogeneous, and free from cavities or other flaws. As an alternative, bushings may be either polymer, composite or of a silicon compound type if needed to pass the seismic requirements of IEEE 693, for the moderate or high seismic requirement ratings. The glazing shall be uniform in color and free from blisters, burns, and other defects. The color of the porcelain, polymer, silicon or composite bushings shall be ANSI 70 gray for oil-filled type VT’S or may be a dark gray, (all-most-black) color when epoxy or butyl rubber type of construction is furnished for dry-type VT’S.

The porcelain parts of each VT bushing rated below 450-kV BIL shall be constructed of one piece.

For VT’S rated 450-kV BIL and above, the porcelain parts may be constructed of one piece or of multiple parts, provided the multiple parts are assembled by one of the following methods:

a. By flanged segments;

b. By placing firing material in the joints between the segments and the entire porcelain part fired in one piece; or

c. By securely holding the parts together with a clamping device through the centerline of the bushing. The joint must be at right angles to the longitudinal centerline of the bushing if this method is used.

Polymer, silicon, or composite type bushings shall consist of a core, housing, and end fittings as required. The outer material shall resist formation of electrical tracking on the surface of the insulating material, resist cracking, prevent hydrolysis (chemical process leading to electrical or mechanical degradation), have electrical and mechanical characteristics as required for the application, provide the necessary creep distance, shall have a life comparable to what a porcelain bushing provides, and withstand sunlight for the entire life of the equipment (resist ultra-violet radiation and pollution).

Bushings shall be molded butyl rubber or molded epoxy resin, which are an integral part of the VT insulation system, for dry type VT’S that are furnished.

2. CONSTRUCTION: The VT’S shall be either dry type or oil-filled type as stated and allowed in tables C-1 through C-8 above. The VT’S shall be suitable for outdoor use, shall be hermetically sealed and shall be completely factory sealed to prevent breathing and absorption of moisture. Expansion tanks external to the main VT tanks will not be acceptable. The base housing shall be of weatherproof construction. For oil-filled VT’S, the insulating liquid shall be the manufacturer’s standard product and shall not contain polychlorinated biphenyls (PCB). The units shall be permanently marked and certification furnished that states there is no PCB present when the equipment is delivered to Western.

Dry type VT’S shall be constructed of a non-tracking insulation such as molded butyl rubber or molded epoxy resin.

3. ACCESSORIES: The oil-filled VTs shall be provided with drain and filling valves or plugs and with liquid level gauges or indicators. Any glass through which oil can be exposed to sunlight shall be capable of filtering out those sunrays that cause oil deterioration.

4. SECONDARIES: Each oil-filled type VT (and Item 124) shall have two electrically separate secondaries, each capable of supplying voltage at both marked ratios. Each dry type VT shall have one secondary for supplying the voltage at the required ratio.

5. PRIMARY TERMINALS: For all oil-filled VTs, each VT shall have line terminals according to NEMA standard line 4-hole terminal pads, conforming to the requirements of NEMA Standard CC 1. Also for the oil-filled VTs, provide on the base of each VT, a ground terminal which can connect to a No. 2 AWG up to a No. 500 KCMIL copper cable.

For dry-type VTs rated below 69-kV, each of the VT’s primary terminals are to be of the solder-less type made of hardened bronze. This terminal is fitted with a hard-copper collar and bronze pressure screw and this collar is semi-captive which allows it to turn 90 degrees in either direction to allow vertical or horizontal cable connections. For vertical and horizontal cable connections, a minimum of No. 10 AWG copper or aluminum cable will connect to this terminal, in the vertical cable position, a maximum of 4/0 AWG will connect to this terminal using aluminum conductor and a maximum of 250 kcmil copper cable will connect vertically. For horizontal cable connections, a maximum of 2/0 AWG aluminum cable will connect and a maximum of 3/0 AWG copper cable can be connected horizontally. Provide a ground terminal on the base plate of the VT which is equal to a ¼-20 inch ground screw welded on the base plate complete with roundhead screw, cup washer, flat washer, and lock washer.

For the dry-type VTs rated at 69-kV, the primary terminal…