Instrument Transformer Reference. Meter and Relay Applications for the Electrical Industry

Transcription

1 Instrument Transformer Reference Meter and Relay Applications for the Electrical Industry

2 Note: For Current and Voltage Transformer Pricing Information refer to: 600 V -PL kv-36 kv -PL The transformers listed in this guide represent those most commonly built for the electric utility industry but are a small sample of what we actually offer. For special designs or units not listed please contact your local ABB representative. VT Voltage Designations 14400/24940Y This unit is rated for operating Volts. It can be connected at Volts line-ground on a Volt system (line to line Volts are V) OR it can be connected line to line on a system with V line to line. This unit is not suitable for operation at Volts. The "Y" indicates it has two fully insulated bushings, suitable for line to line connection /24940GY This unit is rated for operating Volts. It can be connected at Volts line-ground on a Volt system (line to line Volts are V). It CANNOT be connected line to line. The "GY" indicates it only has one fully insulated bushing, making it suitable for line to ground connection only /14400Y This unit is rated for operating Volts. It can be connected at Volts line to line /14400GY This unit is rated for operating Volts. However, it can only be connected line to ground on a V system. Therefore the actual operating voltage of the unit would be 14400/1.73. The accuracy and thermal ratings of this unit are based on V. This is typical where there is a relay connected to the unit which should operate when there is a single line to ground fault. In this condition, the line to ground voltage becomes equal to the line to line voltage. This unit is not suitable for line to line connection as indicated by the "GY". CT Rating Factors: Rating factors given in this brochure are standard at 30ºC. See the thermal loading guide on page for derating for higher average ambient temperatures. Transformers in this booklet conform to the following standards where applicable: 1) IEEE Standard Requirements for Instrument Transformers, C ) ANSI Standard for Instrument Transformers for Metering Purposes, 15 kv and less, C

3 GENERAL INDEX GUIDE 600 VOLT CURRENT TRANSFORMERS Primary Current Type Product Page Bulletin No. 50 thru 1000 IMC thru 800 CBT/ thru 800 CBT-H thru 600 CSF thru 800 CSH thru 300 CMS thru 1200 CMF thru 4000 CMV thru 5000 CMV-HT HT thru 4000 CLC thru 6000 CLE thru 4000 RLC Multi-Ratio AUXILIARY Multi-Ratio A-AUTO thru 3000 OBCT VOLT VOLTAGE TRANSFORMERS Primary Voltage Type Product Page Bulletin No. 240 thru 600 PPW thru 600 PPM thru 480 PPX kv-36 kv CURRENT TRANSFORMERS Class Type Product Page Bulletin No. 5, 8.7 kv Indoor KIR-60, kv Indoor KIR , 8.7 kv Outdoor KOR-60, kv Outdoor KOR kv Outdoor KON kv Outdoor KOR-15C kv Outdoor KOR A kv Outdoor KOT kv Outdoor KOTD kv-36 kv VOLTAGE TRANSFORMERS Class Type Product Page Bulletin No. 5 kv Indoor VIY , 15 kv Indoor VIZ-75, kv Indoor VIZZ-15, 15G kv Outdoor VOY , 15 kv Outdoor VOZ-75, A kv Outdoor VOZ-11M kv Outdoor VOY kv Outdoor VOG kv Outdoor VOY kv Outdoor VOG kv Outdoor VOY-15, 15G kv Outdoor VOZ kv Outdoor VOHD-200, 200G kv Outdoor VOZZ-15, 15G kv Outdoor VOZZ-20, 20G kv Outdoor VOY-20, 20G Application Data Accuracy Standards IT Type Designations Cross-Reference

4 600 V CURRENT TRANSFORMERS TYPE IMC PB Window Dia In. UL Recognized Component 600 Volts Indoor, 10 kv BIL 25 Through 400 Hertz Primary Style IEEE Meter Accuracy Amps Number B0.1 B0.2 B0.5 TYPE IMC TYPE CBT/ A98G A98G A98G A98G A98G A98G A98G A98G A98G A98G A98G Optional Accessory Mtg. Feet Style 9628A05G01 No Base A77G A77G A77G A77G A77G A77G A77G Flat Base A77G A77G A77G A77G A77G A77G A77G High Base A77G A77G A77G A77G A77G A77G A77G

5 TYPE CBT/1 PB Volts Indoor/Outdoor 10 kv BIL 60 Hertz Rating Factor Height Width Length Weight

6 600 V CURRENT TRANSFORMERS TYPE CBT-H PB Volts Indoor/Outdoor 10 kv BIL 60 Hertz TYPE CBT-H Primary Style IEEE Meter Accuracy Amps Number B0.1 B0.2 B0.5 No Base Flat Base High Base A78G A78G A78G A78G A78G A78G A78G A78G A78G A78G A78G A78G A78G A78G A78G A78G A78G A78G Primary Style IEEE Meter Accuracy Amps Number B0.1 B0.2 B0.5 TYPE CSF 1 No Base A85G A85G A83G A83G Flat Base A85G A85G A83G A83G A85G A85G A83G A83G High Base 4 1 Optional Accessory: Primary Bars 1.500" D Style 9628A05G09 *Accuracy 20% less at 50 Hertz.

7 TYPE CSF PB Volts Indoor/Outdoor 10 kv BIL 50/60 Hertz* Rating Factor Height Width Length Weight Rating Window Factor Dia. Height Width Length Weight " D Style 9628A05G10 5

8 600 V CURRENT TRANSFORMERS TYPE CSH PB Window Dia In. 200 & 300 Amps 2.00 In. all other ratings 600 Volts Indoor/Outdoor 10 kv BIL 50/60 Hertz TYPE CSH Primary Style IEEE Meter Accuracy Amps Number B0.1 B0.2 B0.5 No Base A90G A90G A90G A90G A90G A90G Flat Base A90G A90G A90G A90G A90G A90G High Base TYPE CMS A90G A90G A90G A90G A90G A90G A79G A79G No Base A79G A79G Flat Base A79G A79G High Base 6 *Accuracy 20% less at 50 Hertz.

9 TYPE CMS PB Window Dia In. 600 Volts Indoor/Outdoor 10 kv BIL 50/60 Hertz Relay* Rating Accuracy Factor Height Width Length Weight C C C C C C C C C C C C C10 3, C C C C C C C C C C C

10 600 V CURRENT TRANSFORMERS TYPE CMF 600 Volts, Indoor/Outdoor, 10 kv BIL 50/60 Hertz* Window Dia In. 100, 200 & 200/400 Amps 3.06 In. all other ratings Primary Style IEEE Meter Accuracy Amps Number B0.1 B0.2 B0.5 B1.8 With Window and Flat Base With Window and High Base With Primary Bar and Flat Base With Primary Bar and High Base A30G A30G A30G A30G A30G A30G A30G A30G A30G / A30G11 0.3/ / / / A30G13 0.3/ / / / A30G15 0.3/ / / A30G A30G A30G A30G A30G A30G A30G A30G A30G / A30G12 0.3/ / / / A30G14 0.3/ / / / A30G16 0.3/ / / A01G A01G A01G A01G A01G A01G A01G A01G / A01G11 0.3/ / / / A01G13 0.3/ / / / A01G15 0.3/ / / A01G A01G A01G A01G A01G A01G A01G A01G / A01G12 0.3/ / / / A01G14 0.3/ / / / A01G16 0.3/ / /0.3 8 *Accuracy 20% less at 50 Hertz.

11 PB Relay* Rating Accuracy Factor Height Width Length Weight C C C C C C C C C30/C50 4/ C20/C30 2/ C20/C50 2/ C C C C C C C C C30/C50 4/ C20/C30 2/ C20/C50 2/ C C C C C C C C C30/C50 4/ C20/C30 2/ C20/C50 2/ C C C C C C C C C30/C50 4/ C20/C30 2/ C20/C50 2/

12 600 V CURRENT TRANSFORMERS TYPE CMV Window Opening 3.50 x 4.50 In. CMV Primary Style IEEE Meter Accuracy Amps Number B0.1 B0.2 B0.5 B0.9 B1.8 Tapered Bottom A75G A75G A75G A75G A75G A75G A75G A75G A75G A75G A75G A75G A73G A73G A73G A73G A73G A73G A73G Wide Bottom A73G A73G A73G A73G A73G Optional Accessories Mounting Feet 4 pcs. w hdwr., Style #9628A05G15 One Piece Base w hdwr., Style #9628A05G Accuracy 20% less at 50 Hertz.

13 PB Volts, Indoor/Outdoor 10 kv BIL 50/60 Hertz* fits the following bus bar sizes: ¼ " ⅜ " * ½ " * *with modification Accessory: Bus Bar Adapter Style #9628A05G17 (2 pcs.) Supplied with Style #7524A75GXX To order without use Style # 7524A76GXX Relay 1 Rating Accuracy Factor Height Width Length Weight C C C C C C C C C C C C C C C C C C C C C C C C

14 600 V CURRENT TRANSFORMERS TYPE CMV-HT HT refers to CTs designed for high temperature environments. Refer to Product Bulletin for details. Window Opening 3.5 x 4.5 In. 600 Volts Indoor/Outdoor 10 kv BIL Hertz Primary Style IEEE Meter Accuracy Amps Number B0.1 B0.2 B0.5 B0.9 B A231G A231G A231G A231G A231G A231G A231G A231G A231G A231G A231G * Accuracy 20% less at 50 Hertz.

15 PB HT Relay * Rating Accuracy Factor Height Width Length Weight C C C C C C C C C C C

16 600 V CURRENT TRANSFORMERS TYPE CLC Window Dia In. Primary Style IEEE Meter Accuracy Amps Number B0.1 B0.2 B0.5 B0.9 B A58G A58G A58G A58G A58G A58G A58G A58G Without Mounting Feet 600/ A58G08 800/ A58G / A58G / A58G / A58G ➁ ➁ ➁ ➁ ➁ A59G A59G A59G A59G A59G A59G A59G A59G With Mounting Feet 4-Piece 600/ A59G08 800/ A59G / A59G / A59G / A59G ➁ ➁ ➁ ➁ ➁ 14 ➁ Tap Connection X2-X3 *Accuracy 20% less at 50 Hertz.

17 PB Volts, Indoor/Outdoor, 10 kv BIL 50/60 Hertz* Optional Accessories: Mounting Feet-Set of 4 with Hardware 9628A05G20 One Piece Base 9628A05G21 Window Plate-One required 9628A05G22 Primary Bar Assemblies Amps-1 Bar 9628A05G Amps-2 Bars 9628A05G Amps-3 Bars 9628A05G Amps-4 Bars 9628A05G26 Relay* Rating Accuracy Factor Height Width Length Weight C C C C C C C C C C C C C C C C C C C C C C C C C C C C continued on next page 15

18 600 V CURRENT TRANSFORMERS TYPE CLC CONT D. Primary Style IEEE Meter Accuracy Amps Number B0.1 B0.2 B0.5 B0.9 B A60G A60G A60G A60G A60G A60G A60G A60G With One Piece Base 600/ A60G08 800/ A60G / A60G / A60G / A60G ➁ ➁ ➁ ➁ ➁ A61G A61G A61G A61G A61G A61G A61G A61G With Window Plate 600/ A61G08 800/ A61G / A61G / A61G / A61G ➁ ➁ ➁ ➁ ➁ 16 ➁ Tap Connection X2-X3 *Accuracy 20% less at 50 Hertz.

19 PB Relay* Rating Accuracy Factor Height Width Length Weight C C C C C C C C C C C C C C C C C C C C C C C C C C C C

20 600 V CURRENT TRANSFORMERS TYPE CLE Window Dia In. Primary Style IEEE Meter Accuracy Amps Number B0.1 B0.2 B0.5 B0.9 B1.8 Without Mounting Feet A63G A63G A63G A63G A63G , / A63G / A63G / A63G / A63G / A63G A64G A64G A64G A64G A64G / A64G06 With Mounting Feet 1500/ A64G07 2-Piece 2000/ A64G / A64G / A64G ➁ Tap Connection X2-X3 *Accuracy 20% less at 50 Hertz.

21 PB Volts, Indoor/Outdoor, 10 kv BIL 50/60 Hertz Optional Accessories Mounting Feet-Set of 2 w/hdwr. 9628A05G27 Window Plates-Set of 2 w/hdwr. 9628A05G28 Relay* Rating Accuracy Factor Height Width Length Weight C C C C C C C C C C C C C C C C C C C C C C C C

22 600 V CURRENT TRANSFORMERS TYPE RLC Window Dia In. 600 Volts Indoor/Outdoor 10 kv BIL 50/60 Hertz Primary Style IEEE Meter Accuracy Amps Number B0.1 B0.2 B0.5 B0.9 B A52G A52G A52G A52G A52G A52G A52G A52G A52G Standard 600/ A52G / A52G / A52G / A52G / A52G Hi Relay Accuracy A21G A21G A21G A21G / A21G / A21G / A21G Tap Connection X2-X3 *Accuracy 20% less at 50 Hertz.

23 PB Relay* Rating Accuracy Factor Height Width Length Weight C C C C C C C C C C C C C C C C C C C C C C C C C C C C C

24 600 V CURRENT TRANSFORMERS AUXILIARY Indoor Test Voltage: 2500 Volts 25 Through 60 Hertz Multi-Ratio Winding Development tapped wdg part wdg. Style Winding Turns Winding Turns Ratio Number Multi 7881A02G Multi 7881A02G Multi 7881A02G Multi 7881A02G Multi 7881A02G Multi 7881A02G Multi 7881A02G Multi 7881A03G Multi 7881A03G Multi 7881A03G Multi 7881A03G :5 7881A01G :5 7881A01G :5 7881A01G TYPE A CURRENT BALANCING AUTO Indoor Test Voltage: 2500 Volts 25 Through 60 Hertz Type A transformers provide a large number of fine ratio adjustment taps for establishing an exact current ratio balance between the CT's on the input and output sides of power transformers. Volt-Ampere Style Ratio Adjustment Range Rating Number A17G01 from 10.8:5 to 5:5 Amps A17G02 from 10.8:5 to 5:5 Amps. 22

25 PB Dimensions & Weights Multi-Ratio Single-Ratio Height Width Length Weight Typical Accuracy Values at 800 Ampere turns are: Relay Meter Multi-Ratio: T thru B0.5, 0.6 thru B1.8 Single Ratio: T50 Same Auxiliary CT's offer a wide selection of turns ratios for use in changing the overall ratio of main CT's. Available ratios can be determined from the wdg. turns tabulation. The max. continuous current rating of multi-ratio transformers can be calculated as follows: Single ratio auxiliary CTs have a nominal output of 5 amperes and a continuous current rating factor of PB

26 600 V CURRENT TRANSFORMERS TYPE OBCT Primary Style IEEE Meter Accuracy 1 Amps Number B0.1 B0.2 B0.5 B A86G A86G A86G A86G Turns Turns Turns Turns A86G A86G A86G A86G Turns Turns Turns Turns A86G A86G A86G A86G Turns Turns Turns Turns A86G A86G A86G A86G Turns Turns Turns Turns Mounting Brackets, includes mounting hardware Inside Diameter ANSI Bushing Flange Characteristics Bolt Circle Diameter and Number of Bolts and Bolt Size B864G01 589B864G01 589B864G B864G Note: When stacking two bushing current transformers on a common bushing, 24 1 Applies to Normal Ratio Only (Full Winding)

27 PB Multi-Ratio, Externally Mounted Test Voltage: 2500 Volts Hertz Relay 1 Case Case Accuracy ID OD Height Weight C C C C C C C C C C C C C C C C B864G03 589B864G04 589B864G B864G06 bracket 589B864G07 should also be ordered 25

28 600 V VOLTAGE TRANSFORMERS TYPE PPW PB Volts, Indoor and Outdoor 10 kv BIL, 60 Hertz PPW Thermal Rating: 150 Va at 30º C ambient 100 Va at 55º C ambient TYPE PPW Primary Style Voltage Ratio Number 240/416Y 2:1 7526A04G01 288/500Y 2.4:1 7526A04G02 300/520Y 2.5:1 7526A04G03 480/480Y 4:1 7526A04G04 600/600Y 5:1 7526A04G05 TYPE PPM 240/416Y 2:1 7526A10G01 288/500Y 2.4:1 7526A10G02 300/520Y 2.5:1 7526A10G03 480/480Y 4:1 7526A10G04 600/600Y 5:1 7526A10G05 120/120Y 1:1 7526A10G06 480/480Y 2:1 9628A88G07* TYPE PPX 120/208Y 1:1 7525A16G /120Y.578:1 7525A16G03 400/400Y 3.33:1 7525A16G to :1 7525A16G /360Y 1.732:1 7525A16G09 60/104Y.500:1 7525A16G /60 Hertz * 240 V Secondary

29 TYPE PPM and PPX PB Volts, Indoor and Outdoor 10 kv BIL, 60 Hertz PPM Thermal Rating: 500 Va at 30º C ambient 350 Va at 55º C ambient PPX Thermal Rating: 500 Va at 30º C ambient IEEE Meter Accuracy Height Width Length Weight 0.3 Class for W Class for X Burdens Class for W, X, M & Y Burdens W-Y W, 0.6X-Y W, 0.6X-Y W, 0.6X-Y W-Y W-Y

30 5 kv-8.7 kv CURRENT TRANSFORMERS TYPE KIR-60 AND KIR-75 Indoor 60,75 kv BIL 50/60 Hertz* Mechanical Rating: 5 thru 600 Amps, 150 x normal 800 Amps, 110 x normal Thermal Rating: 5 thru 600 Amps, 100 x normal for 1 second 800 Amps, 75 x normal for 1 second Primary Style IEEE Meter Amps Number Accuracy NSV 5.0 kv 60 kv BIL A01G A01G A01G A01G A01G A01G A01G B A01G08 through A01G09 B A01G10 All Ratings A01G A01G A01G A01G A01G A01G A01G A01G21 NSV 8.7 kv 75 kv BIL A02G A02G A02G A02G A02G A02G B A02G07 through A02G08 B A02G09 All Ratings A02G A02G A02G A02G A02G A02G A02G16 28 *Accuracy 20% less at 50 Hertz.

31 PB IEEE Relay* Rating Accuracy Factor Height Width Length Weight T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T

32 15 kv CURRENT TRANSFORMERS TYPE KIR-11 Indoor 110 kv BIL 50/60 Hertz* Mechanical Rating: 5 thru 600 Amps, 150 x normal 800 Amps, 110 x normal Thermal Rating: 5 thru 600 Amps, 100 x normal for 1 second 800 Amps, 75 x normal for 1 second Primary Style IEEE Meter Amps Number Accuracy NSV 15.0 kv 110 kv BIL Single Ratio A03G A03G A03G A03G A03G A03G A03G B A03G08 through A03G09 B A03G10 All Ratings A03G A03G A03G A03G A03G A03G A03G A03G21 NSV 15.0 kv 110 kv BIL Double Ratio 5/ A04G01 10/ A04G02 20/ A04G03 25/ A04G / A04G05 B0.1 75/ A04G06 through 100/ A04G07 B1.8 Full 150/ A04G08 B0.9 Tap 200/ A04G09 All Ratings 300/ A04G10 400/ A04G11 600/ A04G14 30 *Accuracy 20% less at 50 Hertz.

33 PB IEEE Relay* Rating Accuracy Factor Height Width Length Weight T T T T T T T T T T T T T T T T T T T90/T / T90/T / T90/T / T90/T / T90/T / T90/T / T90/T / T90/T / T90/T / T90/T / T100/T / T90/T /

34 5 kv-8.7 kv CURRENT TRANSFORMERS TYPE KOR-60 and KOR-75 Outdoor 60 kv and 75 kv BIL 50/60 Hertz Mechanical Rating: 5 thru 400 Amp; 150 x normal Amp; 110 x normal Thermal Rating: 5 thru 600 Amp; 100 x normal for 1 second 800 Amp; 75 x normal for 1 second 1000 Amp; 50 x normal for 1 second Primary Style IEEE Meter Amps Number Accuracy NSV 5.0 kv 60 kv BIL A10G A10G A10G A10G A10G A10G B A10G07 through A10G08 B A10G09 All Ratings A10G A10G A10G A10G A10G A10G A10G A10G17 NSV 8.7 kv 75 kv BIL A11G A11G A11G A11G A11G A11G B A11G07 through A11G08 B A11G09 All Ratings A11G A11G A11G A11G A11G A11G A11G A11G17 32 *Accuracy 20% less at 50 Hertz.

35 PB IEEE Relay* Rating Accuracy Factor Height Width Length Weight T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T

36 15 kv CURRENT TRANSFORMERS TYPE KOR-11 Outdoor 110 kv BIL 50/60 Hertz Mechanical Rating: 5 thru 600 Amp; 150 x normal 800 Amp. 110 x normal Thermal Rating: 5 thru 600 Amp; 100 x normal for 1 second 800 Amp. 75 x normal for 1 second Primary Style IEEE Meter Amps Number Accuracy A12G A12G A12G A12G A12G A12G B A12G07 through A12G08 B A12G09 All Ratings A12G A12G A12G A12G A12G A12G A12G A12G A12G17 5/ A13G01 10/ A13G02 20/ A13G03 25/ A13G B0.1 50/ A13G05 through 75/ A13G06 B1.8 Full 100/ A13G07 B0.9 Tap 150/ A13G08 All Ratings 200/ A13G09 300/ A13G10 400/ A13G11 600/ A13G12 34 *Accuracy 20% less at 50 Hertz.

37 PB IEEE Relay* Rating Accuracy Factor Height Width Length Weight T T T T T T T T T T T T T T T T T T T90/T / T90/T / T90/T / T90/T / T90/T / T90/T / T90/T / T90/T / T90/T / T90/T / T100/T / T90/T /

38 15 kv CURRENT TRANSFORMERS TYPE KON-11 Mechanical Rating: All Ratings 270 x normal Thermal Rating: All Ratings 190 x normal, 1 second Outdoor 110 kv BIL 50/60 Hertz Primary Style IEEE Meter Amps Number Accuracy A25G A25G A25G A25G A25G A25G A25G A25G B0.1, A25G08 B0.2, B A25G09 All Ratings A25G A25G A25G A25G A25G A25G A25G A25G19 36 *Accuracy 20% less at 50 Hertz.

39 PB IEEE Relay* Rating Accuracy Factor Height Width Length Weight C C C C C C C C C C C C C C C C C C

40 25 kv CURRENT TRANSFORMERS TYPE KOR-15C (THIS REPLACES KOR-15 AND KOR-15B) Mechanical Rating: All styles single ratio 290 x normal All styles double ratio 290 TAP 145 FULL Thermal Rating: All styles 100 x normal, 1 second Primary Style IEEE Meter Amps Number Accuracy Single Ratio 5 923A185G A185G A185G A185G A185G B0.1, A185G06 through A185G07 B A185G08 All Ratings A185G A185G A185G A185G A185G A185G A185G A185G A185G A185G18 Double Ratio 5/10 923A186G01 10/20 923A186G02 20/40 923A186G B0.1 through 25/50 923A186G04 B0.9 Tap 50/ A186G05 B1.8 Full 75/ A186G06 All Ratings 100/ A186G07 150/ A186G08 200/ A186G09 300/ A186G10 400/ A186G11 600/ A186G12 38 *Accuracy 20% less at 50 Hertz.

41 PB Outdoor 150 kv BIL 50/60 Hertz IEEE Relay* Rating Accuracy Factor Height Width Length Weight C All Ratings / / C100 Tap 3.0/ C200 Full 3.0/ All Ratings 3.0/ / / / / / / /

42 36 kv CURRENT TRANSFORMERS TYPE KOR-20 Primary Style IEEE Meter Amps Number Accuracy NSV 36 kv 200 kv BIL Single Ratio A22G A22G A22G A22G A22G A22G B0.1, A22G07 B0.2, B0.5, A22G08 B A22G09 All Ratings A22G A22G A22G A22G A22G A22G A22G A22G17 NSV 36 kv 200 kv BIL Double Ratio 5/ A21G01 10/ A21G02 20/ A21G B0.1 through 25/ A21G04 B0.9 Tap 50/ A21G05 B1.8 Full 75/ A21G06 All Ratings 100/ A21G07 150/ A21G08 200/ A21G09 300/ A21G10 400/ A21G11 600/ A21G12 40 *Accuracy 20% less at 50 Hertz.

43 PB A Outdoor 200 kv BIL 50/60 Hertz IEEE Relay* Rating Accuracy Factor Height Width Length Weight C All Ratings Tap Full C100 Tap C200 Full All Ratings /

44 5 kv-25 kv CURRENT TRANSFORMERS TYPE KOT Outdoor 60, 75, 110, 150 kv BIL 50/60 Hertz Tube Type 3.25 in. ID Primary Style IEEE Meter Amps Number Accuracy KOT-60 Tube Type NSV 5.0 kv 60 kv BIL KOT-75 Tube Type NSV 8.7 kv 75 kv BIL KOT-11 Tube Type NSV 15.0 kv 110 kv BIL KOT-15 Tube Type NSV 25 kv 150 kv BIL A32G01 0.3B A32G02 0.3B A32G03 0.3B A32G04 0.3B A32G05 0.3B A32G06 0.3B / A32G07 0.3B0.5 Tap B1.8 Full 1000/ A32G08 0.3B0.9 Tap B1.8 Full 2000/ A32G09 0.3B1.8 Tap B1.8 Full A33G01 0.3B A33G02 0.3B A33G03 0.3B A33G04 0.3B A33G05 0.3B A33G06 0.3B / A33G07 0.3B0.5 Tap B1.8 Full 1000/ A33G08 0.3B0.9 Tap B1.8 Full 2000/ A33G09 0.3B1.8 Tap B1.8 Full A34G01 0.3B A34G02 0.3B A34G03 0.3B A34G04 0.3B A34G05 0.3B A34G06 0.3B / A34G07 0.3B0.5 Tap B1.8 Full 1000/ A34G08 0.3B0.9 Tap B1.8 Full 2000/ A34G09 0.3B1.8 Tap B1.8 Full A35G01 0.3B A35G02 0.3B A35G03 0.3B A35G04 0.3B A35G05 0.3B A35G06 0.3B / A35G07 0.3B0.5 Tap B1.8 Full 1000/ A35G08 0.3B0.9 Tap B1.8 Full 2000/ A35G09 0.3B1.8 Tap B1.8 Full 42 *Accuracy 20% less at 50 Hertz.

45 PB Mechanical Rating: All units: effectively unlimited Thermal Rating: 800 and 1200 Amp 80 x normal, 1 second 1500 Amp and above 100 x normal, 1 second IEEE Relay* Rating Accuracy Factor Height Width Length Weight C C C C C C C100/C / C100/C / C100/C / C C C C C C C100/C / C100/C / C100/C / C C C C C C C100/C / C100/C / C100/C / C C C C C C C100/C / C100/C / C100/C / Continued on Next Page 43

46 5 kv-25 kv CURRENT TRANSFORMERS TYPE KOT CON T Outdoor 60, 75, 110, 150 kv BIL 50/60 Hertz Bar Type base details on details previous page Primary Style IEEE Meter Amps Number Accuracy KOT-60 Bar Type NSV 5.0 kv 60 kv BIL KOT-75 Bar Type NSV 8.7 kv 75 kv BIL KOT-11 Bar Type NSV 15.0 kv 110 kv BIL KOT-15 Bar Type NSV 25 kv 150 kv BIL A36G01 0.3B A36G02 0.3B A36G03 0.3B A36G04 0.3B A36G05 0.3B A36G06 0.3B / A36G07 0.3B0.5 Tap B1.8 Full 1000/ A36G08 0.3B0.9 Tap B1.8 Full 2000/ A36G09 0.3B1.8 Tap B1.8 Full A37G01 0.3B A37G02 0.3B A37G03 0.3B A37G04 0.3B A37G05 0.3B A37G06 0.3B / A37G07 0.3B0.5 Tap B1.8 Full 1000/ A37G08 0.3B0.9 Tap B1.8 Full 2000/ A37G09 0.3B1.8 Tap B1.8 Full A38G01 0.3B A38G02 0.3B A38G03 0.3B A38G04 0.3B A38G05 0.3B A38G06 0.3B / A38G07 0.3B0.5 Tap B1.8 Full 1000/ A38G08 0.3B0.9 Tap B1.8 Full 2000/ A38G09 0.3B1.8 Tap B1.8 Full A39G01 0.3B A39G02 0.3B A39G03 0.3B A39G04 0.3B A39G05 0.3B A39G06 0.3B / A39G07 0.3B0.5 Tap B1.8 Full 1000/ A39G08 0.3B0.9 Tap B1.8 Full 2000/ A39G09 0.3B1.8 Tap B1.8 Full 44 *Accuracy 20% less at 50 Hertz.

47 PB IEEE Relay* Rating Accuracy Factor Height Width Length Weight C C C C C C C100/C / C100/C / C100/C / C C C C C C C100/C / C100/C / C100/C / C C C C C C C100/C / C100/C / C100/C / C C C C C C C100/C / C100/C / C100/C /

48 5 kv-36 kv CURRENT TRANSFORMERS TYPE KOTD Outdoor 110, 150, 200 kv BIL 50/60 Hertz Tube Type 5 Inch ID Primary Style IEEE Meter Amps Number Accuracy KOTD-110 Tube Type NSV 15 kv, 110 kv BIL 200/ A142G01 0.3B / A142G02 0.3B / A142G03 0.3B / A142G04 0.3B / A142G05 0.3B / A142G06 0.3B / A142G07 0.3B / A142G08 0.3B / A142G09 0.3B / A142G10 0.3B1.8 KOTD-150 Tube Type NSV 25 kv 150 kv BIL 200/ A156G01 0.3B / A156G02 0.3B / A156G03 0.3B / A156G04 0.3B / A156G05 0.3B / A156G06 0.3B / A156G07 0.3B / A156G08 0.3B / A156G09 0.3B / A156G10 0.3B1.8 KOTD-200 Tube Type NSV 36 kv, 200 kv BIL 200/ A170G01 0.3B / A170G02 0.3B / A170G03 0.3B / A170G04 0.3B / A170G05 0.3B / A170G06 0.3B / A170G07 0.3B / A170G08 0.3B / A170G09 0.3B / A170G10 0.3B *Accuracy 20% less at 50 Hertz.

49 PB DIA. HOLE 4 TOTAL FRONT BASE DETAILS PRIMARY POLARITY MARKER NAMEPLATE IEEE Relay* Rating Accuracy Factor Height Width Length Weight C100/ / C100/ / C200/ / C200/ / C200/ / C200/ / C400/ / C400/ / C400/ / C400/ / C100/ / C100/ / C200/ / C200/ / C200/ / C200/ / C400/ / C400/ / C400/ / C400/ / C100/ / C100/ / C200/ / C200/ / C200/ / C200/ / C400/ / C400/ / C400/ / C400/ / Continued on Next Page 47

50 15 kv-36 kv CURRENT TRANSFORMERS TYPE KOTD CON T Outdoor 110, 150, 200 kv BIL 50/60 Hertz Bar Type base detail on previous page Primary Style IEEE Meter Amps Number Accuracy* KOTD-110 Bar Type NSV 15 kv, 110 kv BIL 200/ A148G01 0.3B / A148G02 0.3B / A148G03 0.3B / A148G04 0.3B / A148G05 0.3B / A148G06 0.3B / A148G07 0.3B / A148G08 0.3B / A148G09 0.3B / A148G10 0.3B1.8 KOTD-150 Bar Type NSV 25 kv, 150 kv BIL 200/ A162G01 0.3B / A162G02 0.3B / A162G03 0.3B / A162G04 0.3B / A162G05 0.3B / A162G06 0.3B / A162G07 0.3B / A162G08 0.3B / A162G09 0.3B / A162G10 0.3B1.8 KOTD-200 Bar Type NSV 36 kv 200 kv BIL 200/ A176G01 0.3B / A176G02 0.3B / A176G03 0.3B / A176G04 0.3B / A176G05 0.3B / A176G06 0.3B / A176G07 0.3B / A176G08 0.3B / A176G09 0.3B / A176G10 0.3B *Accuracy 20% less at 50 Hertz.

51 PB IEEE Relay Rating Accuracy Factor Height Width Length Weight C100/ / C100/ / C200/ / C200/ / C200/ / C200/ / C400/ / C400/ / C400/ / C400/ / C100/ / C100/ / C200/ / C200/ / C200/ / C200/ / C400/ / C400/ / C400/ / C400/ / C100/ / C100/ / C200/ / C200/ / C200/ / C200/ / C400/ / C400/ / C400/ / C400/ /

52 5 kv VOLTAGE TRANSFORMERS TYPE VIY-60 Thermal Rating VA at 30ºC 700 VA at 55ºC Indoor 60 kv BIL 60 Hertz Primary Style Voltage Ratio Number Unfused 2400/4160Y 20:1 7525A50G /4200Y 35:1 7525A50G /4800Y 40:1 7525A50G03 2 Fuses 2400/4160Y 20:1 7525A51G /4200Y 35:1 7525A51G /4800Y 40:1 7525A51G03 1 Fuse 2400/4160GY 20:1 7525A52G /4200GY 2 35:1 7525A52G /4800GY 2 40:1 7525A52G Thermal and Accuracy ratings are at 120 V secondary voltage.

53 PB IEEE Meter Accuracy 1 Height Width Length Weight 0.3W, X, M, Y W, X, M, Y W, X, M, Y W, X, M, Y W, X, M, Y W, X, M, Y W, X, M, Y W, X, M, Y W, X, M, Y Fluxed for line-to-line Voltage; when connected line-to-ground, normal secondary Voltage is 69.3 Volts. 51

54 8.7 kv and 15 kv VOLTAGE TRANSFORMERS TYPE VIZ-75 AND VIZ-11 Indoor 75 kv and 110 kv BIL 60 Hertz Thermal Ratings: VA at 30ºC 1000 VA at 50ºC Primary Style Voltage Ratio Number VIZ kv BIL Unfused VIZ kv BIL Unfused VIZ kv BIL 2 Fuses VIZ kv BIL 2 Fuses VIZ kv BIL 1 Fuse VIZ kv BIL 1 Fuse 2400/4160Y 20:1 7525A66G /7280Y 35:1 7525A66G /8320Y 40:1 7525A66G /7200Y 60:1 7525A66G /12470Y 60:1 7525A66G /14560Y 70:1 7525A66G /12000Y 100:1 7525A66G /14400Y 120:1 7525A66G /4160Y 20:1 7525A67G /7280Y 35:1 7525A67G /8320Y 40:1 7525A67G /7200Y 60:1 7525A67G /12470Y 60:1 7525A67G /14560Y 70:1 7525A67G /12000Y 100:1 7525A67G /14400Y 120:1 7525A67G /4160GY 20:1 7525A68G /7280GY 35:1 7525A68G /8320GY 40:1 7525A68G /7200GY 2 60:1 7525A68G /12470GY 60:1 7525A68G /14560GY 70:1 7525A68G /12000GY 2 100:1 7525A68G /14400GY 2 120:1 7525A68G10 1 Thermal and Accuracy ratings are at 120 V secondary voltage. 2 Fluxed for line-to-line voltage; when connected line-to-ground, normal secondary voltage is 69.3 Volts. 52

55 PB IEEE Meter Accuracy 1 Height Width Length Weight 0.3W, X, M, Y, Z W, X, M, Y, Z W, X, M, Y, Z W, X, M, Y, Z W, X, M, Y, Z W, X, M, Y, Z W, X, M, Y, Z W, X, M, Y, Z W, X, M, Y, Z W, X, M, Y, Z W, X, M, Y, Z W, X, M, Y, Z W, X, M, Y, Z W, X, M, Y, Z W, X, M, Y, Z W, X, M, Y, Z W, X, M, Y, Z W, X, M, Y, Z W, X, M, Y, Z W, X, M, Y, Z W, X, M, Y, Z W, X, M, Y, Z

56 25 kv VOLTAGE TRANSFORMERS TYPE VIZZ-15 AND VIZZ-15G Indoor 150 kv BIL 60 Hertz Available at other ratios and single tapped secondary or double secondary. Thermal Ratings: 3000 VA at 30ºC Ambient Primary Style Voltage Ratio Number VIZZ kv BIL 12000/20800Y 100:1 7525A82G /24940Y 120:1 7525A82G /18000Y 150:1 7525A82G /24000Y 200:1 7525A82G04 *VIZZ-15G 150 kv BIL 12000/20800GY 100:1 7524A84G /24940GY 120:1 7524A84G /20000GY :1 7524A84G /24000GY 200:1 7524A84G /18000GY 150:1 7524A84G05 *Single bushing 54 1 Style with Clamp Type Primary Terminal. Stud Type available.

57 PB IEEE Meter Accuracy Height Width Length Weight 0.3W, X, M, Y, Z, ZZ W, X, M, Y, Z, ZZ W, X, M, Y, Z, ZZ W, X, M, Y, Z, ZZ W, X, M, Y, Z, ZZ W, X, M, Y, Z, ZZ W, X, M, Y, Z, ZZ W, X, M, Y, Z, ZZ W, X, M, Y, Z, ZZ

58 5 kv, 8.7 kv and 15 kv VOLTAGE TRANSFORMERS TYPE VOY-60 Outdoor 60 kv BIL 60 Hertz Thermal Rating: 1000 VA at 30ºC ambient Primary Style Voltage Ratio Number 2400/4160Y 20:1 7525A85G /4200Y 35:1 7525A85G /4800Y 40:1 7525A85G03 TYPE VOZ-75 and VOZ-11 Outdoor 75 kv and 110 kv BIL 60 Hertz Thermal Rating: 1500 VA at 30ºC ambient 2400/4160Y 20:1 7525A89G /7280Y 35:1 7525A89G /8320Y 40:1 7525A89G /7200Y 60:1 7525A89G /12470Y 60:1 7525A89G /13200Y 63.5:1 7525A89G /14560Y 70:1 7525A89G /12000Y 100:1 7525A89G /13200Y 110:1 7525A89G /14400Y 120:1 7525A89G10 56

59 PB A IEEE Meter Accuracy Height Width Length Weight 0.3W, X, M, Y W, X, M, Y W, X, M, Y PB W, X, M, Y, Z W, X, M, Y, Z W, X, M, Y, Z W, X, M, Y, Z W, X, M, Y, Z W, X, M, Y, Z W, X, M, Y, Z W, X, M, Y, Z W, X, M, Y, Z W, X, M, Y, Z

60 15 kv VOLTAGE TRANSFORMERS TYPE VOZ-11M Outdoor 110 kv BIL 60 Hertz Thermal Rating: 1500 VA at 30ºC ambient Primary Style Voltage Ratio Number VOZ-11M 110 kv BIL 7200/12470GY 60:1 7525A91G /13200GY 63.5:1 7525A91G /14560GY 70:1 7525A91G07 TYPE VOY-11 Outdoor 110 kv BIL 60 Hertz Thermal Rating: 1500 VA at 30ºC ambient Primary Style Voltage Ratio Number 7200/12470Y 60:1 7525A23G /13200Y 63.5:1 7525A23G /14560Y 70:1 7525A23G /12000Y 100:1 7525A23G /13200Y 110:1 7525A23G /14400Y 120:1 7525A23G10 TYPE VOG-11 Outdoor 110 kv BIL 60 Hertz Thermal Rating: 1000 VA at 30ºC ambient Primary Style Voltage Ratio Number 7200/12470GY 60:1 7525A95G /13200GY 63.5:1 7525A95G /14560GY 70:1 7525A95G03 58

61 PB A IEEE Meter Accuracy Height Width Length Weight 0.3W, X, M, Y, Z W, X, M, Y, Z W, X, M, Y, Z PB IEEE Meter Accuracy Height Width Length Weight 0.3W, X, M, Y W, X, M, Y W, X, M, Y W, X, M, Y W, X, M, Y W, X, M, Y PB IEEE Meter Accuracy Height Width Length Weight 0.3W, X, M, Y W, X, M, Y W, X, M, Y

62 25 kv VOLTAGE TRANSFORMERS TYPE VOY-12 Outdoor 125 kv BIL 60 Hertz Thermal Ratings: 1000 VA at 30ºC ambient Primary Style Voltage Ratio Number VOY kv BIL 12000/20780Y 100:1 7525A87G /24940Y 120:1 7525A87G /18000Y 150:1 7525A87G /24000Y 200:1 7525A87G04 TYPE VOG-12 Primary Style Voltage Ratio Number 12000/20780GY 100:1 7525A97G /24940GY 120:1 7525A97G02 Thermal Ratings: 750 VA at 30ºC ambient 60

63 PB IEEE Meter Accuracy Height Width Length Weight 0.3W, X, M, Y W, X, M, Y W, X, M, Y W, X, M, Y The mounting base is the same as VOG-11 PB IEEE Meter Accuracy Height Width Length Weight 0.3W, X, M, Y W, X, M, Y

64 25 kv VOLTAGE TRANSFORMERS TYPE VOY-15 and VOY-15G Outdoor 150 kv BIL 60 Hertz Thermal Ratings: 1000 VA at 30ºC ambient Primary Style Voltage Ratio Number 12000/20780Y 100:1 7526A62G /24940Y 120:1 7526A62G /18000Y 150:1 7526A62G /20000Y 166.7:1 7526A62G /24000Y 200:1 7526A62G /20780GY 100:1 7526A63G /24940GY 120:1 7526A63G02 TYPE VOZ-15 Outdoor 150 kv BIL 60 Hertz Thermal Ratings: 2000 VA at 30ºC ambient Primary Style Voltage Ratio Number 12000/20780Y 100:1 7525A90G /24940Y 120:1 7525A90G /18000Y 150:1 7525A90G /24000Y 200:1 7525A90G04 62

65 PB IEEE Meter Accuracy Height Width Length Weight 0.3W, X, M, Y W, X, M, Y W, X, M, Y W, X, M, Y W, X, M, Y W, X, M, Y W, X, M, Y PB IEEE Meter Accuracy Height Width Length Weight 0.3W, X, M, Y, Z W, X, M, Y, Z W, X, M, Y, Z W, X, M, Y, Z

66 25 kv AND 36 kv VOLTAGE TRANSFORMERS TYPE VOHD-200 AND VOHD-200G Outdoor 200 kv BIL 60 Hertz Thermal Ratings: 1000 VA at 30ºC Ambient Primary Style Voltage Ratio Number* 20125/34500Y 175/300:1 7882A31G /27600Y 240/400:1 7882A31G /34500Y 300/500:1 7882A31G /34500GY 175/300:1 9629A95G01 TYPE VOZZ-15 and VOZZ-15G Outdoor 150 kv BIL 60 Hertz Thermal Ratings: 3000 VA at 30ºC Ambient Available with double secondaries and tapped double secondaries. Primary Style Voltage Ratio Number* 12000/20800Y 100:1 7525A93G01 VOZZ kv BIL 14400/24940Y 120:1 7525A93G /18000Y 150:1 7525A93G /24000Y 200:1 7525A93G04 VOZZ-15G 150 kv BIL 12000/20800GY 100:1 7525A98G /24940GY 120:1 7525A98G02 Single Bushing 64 *Available in stud type terminals.

67 PB IEEE Meter Accuracy Height Width Length Weight 0.3W, X, M, Y Full and Tap 0.3W, X, M, Y Full and Tap 0.3W, X, M, Y Full and Tap 0.3W, X, M, Y Full and Tap PB IEEE Meter Accuracy Height Width Length Weight 0.3W, X, M, Y, Z, ZZ 0.3W, X, M, Y, Z, ZZ 0.3W, X, M, Y, Z, ZZ 0.3W, X, M, Y, Z, ZZ 0.3W, X, M, Y, Z, ZZ W, X, M, Y, Z, ZZ

68 36 kv VOLTAGE TRANSFORMERS TYPE VOZZ-20 and VOZZ-20G Outdoor 200 kv BIL 60 Hertz Thermal Ratings: 3000 VA at 30ºC Ambient Primary Style Voltage Ratio Number /27600Y 240 & 240:1 9629A96G /34500Y 300 & 300:1 9629A96G /34500GY 175/300:1 9629A97G01 & 175/300: /34500GY. 175/300:1 7882A42G01 Tapped and Single Secondaries Available. TYPE VOY-20 and VOY-20G Outdoor 200 kv BIL 60 Hertz Thermal Ratings: 1000 VA at 30ºC Ambient Primary Style Voltage Ratio Number VOY kv BIL 27600/27600Y 240:1 7881A82G /34500Y 275:1 7881A82G04 VOY-20G 200 kv BIL 20125/34500GY 175/300:1 7526A55G Style includes clamp type primary terminals. Stud type available for spade terminal.

69 PB IEEE Meter Accuracy Height Width Length Weight 0.3W, X, M, Y, Z, ZZ 0.3W, X, M, Y, Z, ZZ 0.3W, X, M, Y, Z, ZZ 0.3W, X, M, Y, Z, ZZ PB IEEE Meter Accuracy Height Width Length Weight 0.3W, X, M, and Y W, X, M, and Y W, X, M, and Y

70 APPLICATION DATA Polarity: Designation of the relative instantaneous directions of the currents entering the primary leads and leaving the secondary leads. When current is flowing toward the marked primary lead, it is flowing away from the transformer in the marked secondary lead. 68

71 INSTRUMENT TRANSFORMERS insulate meters or other instruments from high voltages and currents and transform them (i.e., step-down) to values where they can be measured by standard meters. All instrument transformers are classified as either current transformers or voltage transformers. They are used for revenue metering and also with relays and indicating instruments. Current Transformers (CT) The primary windings of current transformers are connected in series with the line and their secondaries connected to the current coils or elements of meters, relays or instruments. All standard current transformers have a 5 Ampere rated secondary regardless of their primary current. Each current transformer has specifications based on continuous current, short time current, and mechanical stress. There are two accuracy classifications: one for metering and one for relaying. The metering accuracy classification tells what error in transformation can be expected at normal currents. The relaying accuracy classification tells what percent accuracy can be expected when the secondary is called upon to induce a certain voltage. The secondary of the current transformer should always be connected to a load (burden) or short circuited. If the secondary is open circuited, the transformer may develop a dangerously high secondary voltage. Rating Factor: The factor by which the nameplate primary current of a CT is multiplied to obtain maximum primary current that can be carried continuously without exceeding the limiting temperature rise. The accuracy class at the rating factor point should be the same as at nameplate rating. Voltage Transformers (VT) The primary windings of voltage transformers are connected across the line. They step down the line voltage to a value suitable for standard meters, normally 115 Volts or 120 Volts. In basic construction, voltage transformers are much like distribution transformers except that the current and the kva capacity are very low. They are designed to give an accurate voltage transformation. Selection A number of considerations are involved in selecting proper instrument transformers including: system voltage, BIL, load current, rating factor and accuracy class at specified burdens. Physical requirements such as indoor or outdoor installation, window or bar type (for 600 V CTs), and window diameter are also important. Many of the transformer types listed in this catalog have some characteristics that are duplicated in other types listed, but each type has its own unique combination of features that best meet the application for which it was designed. Continued on Next Page 69

72 APPLICATION DATA AMPERE CAPACITY OF INSULATED CONDUCTORS Single Conductor In Free Air At 30 C (86 F) Types RUW Types RH Size T RHW AWG Approximate TW RUH or Diameter THW MCM (inches) Cu AI Cu AI CALCULATION OF LINE AMPERES ON POLYPHASE CIRCUITS Amps = Load KVA X X Line To Line Voltage Applicable to both 3 phase 3 wire delta and 3 phase 4 wire wye. REQUIRED DIAMETER OF CT WINDOW FOR MULTIPLE CONDUCTOR Number of Primary Conductors Minimum Window Diameter X Conductor O.D X Conductor O.D X Conductor O.D X Conductor O.D. 70

73 Typical burden value (per stator) ABB Type D5 Polyphase Meters Class 20 Transformer Rated Potential coil at 120 Volts: 6.8 VA at 14 percent power factor. Current coil at 2.5 Amps: 1. 2 VA at 22 percent power factor.(2½ Amp meter) Resistance of copper secondary wire in ohms per 1000 feet at 68 F (20 C). Wire Size Ohms COMMON ELECTRICAL TERMS Ampere (I) = Unit of current or rate of flow of electricity Volt (E) = Unit of electromotive force Ohm (R) = Unit of resistance Ohm's Law E = IR Volt Amperes (VA) = Unit of apparent power = El (single phase) = E x I x 1.73 ( 3 phase) Kilovolt Amperes (kva) = 1000 Volt-Amperes Watt W = Unit of true power = VA x p-f = hp Kilowatt (kw) = 1000 watts Power Factor (p-f) = ratio of true to apparent power W kw = or VAkVA Watthour (WHR) = unit of electrical work = one watt for one hour = Btu = ft. lbs. Kilowatthour (kwhr) = 1000 watthours Horsepower (hp) = Measure of time rate of doing work = Equivalent of raising 33,000 lbs. one ft. in one minute = 746 watts Demand Factor = Ratio of maximum demand to the total connected load Diversity Factor = Ratio of the sum of individual maximum demands of the various subdivisions of a system to the maximum demand of the whole system Load Factor = Ratio of the average load over a designated period of time to the peak load occuring in that period 71

74 ACCURACY STANDARDS Current Transformers The accuracy classification of current transformers for metering service includes a correlation between ratio correction factor and phase angle so as to show the overall effect on watthour meter registration. The classification is based on the requirement that the transformer correction factor (the correction for overall error due to both ratio error and phase angle) be within the limits specified. For any particular accuracy class the ratio correction factor and phase angle must fall within the parallelograms for 100% and 10% current respectively. For example, the overall correction will never exceed.3% at 100% rated current for a transformer in the 0.3 accuracy class. If the ratio correction factor is the maximum allowable phase angle is minutes. The transformer correction factor is: The corresponding ratio correction factor and phase angle for any point inside the 0.3 class parallelogram for 100% rated current will always give a transformer correction factor between.997 and Standard Burden Characteristics 60 Hz and 5 Ampere secondary Burden Resistance Inductance Impedance Volt- Power Designation Ohms Millihenrys Ohms Amperes Factor Metering Burdens B B B B B Relaying Burdens B B B B *Based on.6 Power Factor (lagging) of metered load.