Transformer Technology Seminar What to consider at Design Reviews

Transcription

1 Pomona CA, May 24-25, 2016 Transformer Technology Seminar Siemens AG Transformers siemens.com/answers

2 Why to perform Design Review Meetings? To ensure both parties having the same understanding of the contract, the application and the requirements of the applicable standards and specification. It gives the opportunity for both parties to examine the transformer design to ensure that it will fulfill the requirements, i.e. the technical and also those relating to other aspects of the contract. The manufacturer can verify the use of proven materials, design tools and experience to make sure the transformer will meet the intended performance in service. It gives the chance for an interchange of information between the purchaser and the manufacturer: The purchaser can get a better understanding of the technical capabilities of the manufacturer. The manufacturer can get a better understanding of the needs of the purchaser. Page 2

3 The CIGRE WG A2.36 Task Force 2 gives a Proposal to the Subjects of a Design Review Meeting: 1. Purchaser specification 2. Supplier quotation 3. Applicable standards 4. Plans (quality, production, test, transport and site erection and commissioning) 5. System data 6. Environmental data 7. Transformer design 8. Transformer ancillaries and accessories 9. Fabrication 10.Testing 11.Nameplate 12.Transportation 13.Site erection and commissioning 14.Risk assessments 15.Methods statements (how you do it and why) 16.Health and safety requirements 17.Operation and maintenance manuals 18.Contract documents 19.Document submission time schedules Page 3

4 The Transformer Design will consume most of the attention. Transformer Design Example for the Agenda: Main technical data Core Winding arrangement Type of windings and conductors Dielectric design Short circuit capability Losses Thermal design Leakage flux control Sound level Calculation of leads gradients Page 4

5 Main Technical Data Summary of applied standards and customer specifications Main transformer data: overview of guaranteed values e.g. rated power, voltage ratios, operating voltage, vector group, ambient temperature, temperature rise limits, impedance, Core General description of the core: form and joint design, material, geometry and cross-section area, core flux density For example 2/0 core: Page 5

6 Core Information on tie bars Information on cooling ducts and split of the first core stacks Heating due to stray flux: Temperature rise of the core Heating due to core flux: Page 6

7 Winding Arrangement General arrangement: diameter, spacing between windings and clearance from windings to ground top yoke core LV: 55 turns Ø 1122 Ø Ø 1066 semiconducting shield HV: 819 turns 52 adjacent HV Ø 1472 Ø bottom yoke Page 7 Schematic connection diagram

8 Type of Windings and Conductors Detailed description of the winding and the used conductors For example LV winding (helical winding) For example HV winding (disc winding with middle entrance) Page 8

9 Dielectric Design Overview of dielectric test voltages Duct voltages Maximum turn-turn voltages Duct details Voltage distribution in a HV disc winding: Shown are the spacers from the voltage inlet to the bottom of the winding: Page 9

10 Dielectric Design Voltages between the windings: BIL CW: LV to core Page 10

11 Dielectric Design Voltage at HV winding bottom end to the yoke: 140kV AC applied voltage Page 11

12 Short Circuit Capability Under consideration of: system fault capacity (e.g. infinite bus), asymmetric peak current factor, pre-fault voltage and winding offset Free buckling mode Radial stress: compressive / tensile stress Axial stress on spacers Forced buckling mode Axial bending Radial bending F peak Typical Short Circuit Current & Short Circuit Force Short circuit starts at voltage zero 25 I SC (ka), F SC (kn) 20 I peak Page t (ms)

13 Losses Summary of guaranteed losses: no-load, load losses and auxiliary losses Summary of calculated losses Example for losses in the region of the hot spot disc: Page 13

14 Thermal Design Summary of guaranteed temperature rises: hot spot, average winding and top oil Overview of the cooling system: type of cooling, cooling stages Summary of calculated temperature rises Example for a temperature diagram: Example for the temperature distribution Page 14 (top of HV winding):

15 Leakage Flux Control FEM 3D calculation of the active part and tank Dimensioning of magnetic yoke shunts and tank shunts Definition of non magnetic parts of the tank => reduce tank losses and avoid excessive heating of tank and clamping parts Example for a FEM 3D model: Field plot: Thermal plot: Page 15

16 Sound Level Guaranteed sound level: no-load noise, load noise Calculated sound level Page 16

17 Calculation of Lead-Dimensions Description of electrical connection Calculated temperature rise Electric field calculation Page 17

18 Siemens AG - Transformers Contact Martin Stössl Head Global Technology Centre E T TR LPT GTC Elingasse Weiz Austria Phone: +43 (51707) Mobile: +43 (664) martin.stoessl@siemens.com siemens.com/transformers Page 18