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1 PJH Charlotte, NC March 18, 2008 Liquid Dielectric Test Tables Task Force (C57.12.00) Rev 17 Porto, Portugal October 7, 2008.

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Presentation on theme: "1 PJH Charlotte, NC March 18, 2008 Liquid Dielectric Test Tables Task Force (C57.12.00) Rev 17 Porto, Portugal October 7, 2008."— Presentation transcript:

1 1 PJH Charlotte, NC March 18, 2008 Liquid Dielectric Test Tables Task Force (C ) Rev 17 Porto, Portugal October 7, 2008

2 2 PJH Charlotte, NC March 18, 2008 AGENDA 1. Introductions 2. Mission & Scope 3. Minutes & Review from March Charlotte Meeting 4. Document Status A. Present Form B. C R with proposed Text revisions 6. Future Considerations: Propose disbanding Taskforce 7. Discussion and Adjournment Liquid Dielectric Test Tables Task Force (C )

3 3 PJH Charlotte, NC March 18, 2008 Liquid Dielectric Test Tables Task Force (C )

4 4 PJH Charlotte, NC March 18, 2008 Clean Up Inconsistencies Harmonize with IEC 76-3 Provide Reference Considerations Simplify Tables Mission & Scope Liquid Dielectric Test Tables Task Force (C )

5 5 PJH Charlotte, NC March 18, 2008 IEEE C /12.01/IEC 76-3 Dielectric Test Tables Survey Tally

6 6 PJH Charlotte, NC March 18, 2008 IEEE C /12.01/IEC 76-3 Dielectric Test Tables: New Proposed C Sections Comments and Proposed Disposition

7 7 PJH Charlotte, NC March 18, 2008

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11 11 PJH Charlotte, NC March 18, 2008 Table III Test Values For Repaired Transformers 1.Transformers in the field do not get impulse tests. 2.Transformers that are returned to the factory with field service are to be tested at 85% of the new values. 3.Transformers that have minor repairs or where only one coil is replaced generally are also tested to 85% of the new values. 4. Transformers where 2 or more coils are replaced are generally tested to full rated values. There is naturally a requirement for agreement between purchaser and supplier.

12 12 PJH Charlotte, NC March 18, 2008 Future Direction for Taskforce: 1.Place Task Force on idle while C R is balloted. 2.Address issues in C that are referred back to Taskforce. 3.Disband Taskforce at Spring 2009 meeting in Miami.

13 13 PJH Charlotte, NC March 18, 2008 Summary of Blumes Dielectric Relationships of Test Valves to System Voltage in Low Frequency 2.High Frequency 1 Minute withstand voltage Infinite time withstand voltage 1.5 Full wave withstand 1.5 x 40µsec 60 Hz withstand time Full wave withstand Multiple strokes 1.25 (Page 388*) (Page 473*) (Page 476*) *Transformer Engineering: A Treatise on the Theory, Operation and Application of Transformers By L.F. Blume,, G. Camilli, A. Boyajian and V.M. Montsinger. © 1938 John Wiley and Sons, Inc.

14 14 PJH Charlotte, NC March 18, 2008 Minimum BIL Selection from Surge Arrester Characteristics V1V1 V2V2 Arrester protection level V arrester protection level to V MX L-G From Blume: Minimum BIL = 1.25 X V 2 V MX L-G

15 15 PJH Charlotte, NC March 18, 2008 Grounded Wye-Connected Arresterd Application Chart In Accordance with C62.2 Methods Courtesy of Mike Comber, Ohio Brass Co. Rev.: 0 Date: 11/2/99 1) Shielded Systems use 10 kA discharge voltage protection levels 2) Unshielded Systems use 40 kA discharge voltage protection levels 3) Transmission and subtransmission systems are shielded, having the neutral (ground) lead physically located above the line leads. 4) Distribution systems through 69 kV are normally unshielded with the neutral located below the line leads.

16 16 PJH Charlotte, NC March 18, 2008 Delta-Connected Arresterd Application Chart In Accordance with C62.2 Methods Courtesy of Mike Comber, Ohio Brass Co. Rev.: 0 Date: 11/2/99 1) Shielded Systems use 10 kA discharge voltage protection levels 2) Unshielded Systems use 40 kA discharge voltage protection levels 3) Transmission and subtransmission systems are shielded, having the neutral (ground) lead physically located above the line leads. 4) Distribution systems through 69 kV are normally unshielded with the neutral located below the line leads.

17 17 PJH Charlotte, NC March 18, 2008 Porcelain Housed Station Class Arresters

18 18 PJH Charlotte, NC March 18, 2008 DynaVar Type VH5 Heavy Duty Station Class Gapped Metal-Oxide Surge Arresters (Double Column of Value Elements) 1) Maximum discharge voltage for an impulse current wave which produces a voltage wave creating a s. Discharge currents are 15 kVA for 304=340 MCOV and 30 kA for 462 MCOV. This can be used for coordination where front-of-wave sparkover formerly was used. 2) Discharge voltage of 3 kA for a surge of 45 s time to crest.

19 19 PJH Charlotte, NC March 18, 2008 BACKGROUND INFORMATION George Iliff Reference (Bonneville Power) Low Frequency Tests - Induce and Applied Figure 1 - Voltage Relationhips on faulted windings V Test = 2 x V system A - NORMAL B - FAULT ON UNGROUNDED SYSTEM C - FAULT ON EFFECTIVELY GROUNDED SYSTEM NOTE: G REFERS TO THE GROUND VOLTAGE AT THE TRANSFORMER, RELATIVE TO THE LINE TERMINAL VOLTAGES. THIS DETERMINES THE COLTAGE IMPOSED ON THE TRANSFORMER INSULATION. 100% H2H2 58% G H3H3 H1H1 H2H2 H3H3 H1H1 G R N100%58% H2H2 H3H3 H1H1 G R = O

20 20 PJH Charlotte, NC March 18, 2008 Low Frequency Test Comparison Liquid Dielectric Test Tables Task Force (C )

21 21 PJH Charlotte, NC March 18, 2008 High Frequency Test Comparison Liquid Dielectric Test Tables Task Force (C )


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