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Transformer Technology SeminarWhat to consider at Design Reviews

Pomona CA, May 24-25, 2016

Siemens AG – Transformers

© Siemens AG 2016 All rights reserved.

Why to perform Design Review Meetings?

Siemens Transformer Technology SeminarWhat to consider at Design Reviews

Page 2

• To ensure both parties having the same understanding of the contract, theapplication and the requirements of the applicable standards and specification.

• It gives the opportunity for both parties to examine the transformer design to ensurethat it will fulfill the requirements, i.e. the technical and also those relating to otheraspects of the contract.

• The manufacturer can verify the use of proven materials, design tools andexperience to make sure the transformer will meet the intended performance inservice.

• It gives the chance for an interchange of information between the purchaser and themanufacturer:

• 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 3

1. Purchaser specification

2. Supplier quotation

3. Applicable standards

4. Plans (quality, production, test, transportand 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 andwhy)

16.Health and safety requirements

17.Operation and maintenance manuals

18.Contract documents

19.Document submission time schedules

The CIGRE WG A2.36 Task Force 2 gives a Proposal to the Subjects of a DesignReview Meeting:



Page 4

• 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

The Transformer Design will consume most of the attention.

Transformer Design – Example for the Agenda:



Page 5

• Summary of applied standards and customer specifications

• Main transformer data: overview of guaranteed values e.g. rated power, voltageratios, operating voltage, vector group, ambient temperature, temperature riselimits, impedance, …

Main Technical Data

Core

• General description of the core: form and joint design, material, geometry andcross-section area, core flux density

For example 2/0 core:



Page 6

• Information on tie bars

• Information on cooling ducts and split of the first core stacks

• Temperature rise of the core

Core

Heating due tocore flux:

Heating due tostray flux:



Page 7

• General arrangement: diameter,spacing between windings andclearance from windings to ground

Winding Arrangement

• Schematic connection diagram

top yoke

bottom yoke

core

Ø 1122Ø 1222

50

173

81

125

LV:

55tu

rns

Ø 1472Ø 1680

104

189

97H

V:81

9tu

rns

Ø 1066

adja

cent

HV

52

28

sem

icon

duct

ing

shie

ld



Page 8

• Detailed description of the winding and the used conductors

Type of Windings and Conductors

• For example LV winding (helicalwinding)

• For example HV winding (disc windingwith middle entrance)



Page 9

• Overview of dielectric test voltages

• Duct voltages

• Maximum turn-turn voltages

• Duct details

Voltage distribution in a HVdisc winding:Shown are the spacers from the voltageinlet to the bottom of the winding:

Dielectric Design



Page 10

Voltages between the windings:

Dielectric Design

BIL CW: LV to core



Page 11

Voltage at HV winding bottom end tothe yoke:

140kV AC applied voltage

Dielectric Design


• Under consideration of: system fault capacity (e.g. infinite bus), asymmetric peakcurrent 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


Page 12

Short Circuit Capability

Typical Short Circuit Current & Short Circuit ForceShort circuit starts at voltage zero

-15

-10

-5

0

5

10

15

20

25

30

35

0 10 20 30 40 50 60

t (ms)

I SC

(kA

),F S

C(k

N) Ipeak

Fpeak


• 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

Losses


• 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:


Page 14

Thermal Design

Example for the temperature distribution

(top of HV winding):


• 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


Page 15

Leakage Flux Control

Example for a FEM 3D model: Field plot: Thermal plot:


• Guaranteed sound level: no-load noise, load noise

• Calculated sound level


Page 16

Sound Level



Page 17

Calculation of Lead-Dimensions

• Description of electrical connection

• Calculated temperature rise

• Electric field calculation

© Siemens AG 2016 All rights reserved.Page 18

Siemens AG - TransformersContact

Martin StösslHead – Global Technology CentreE T TR LPT GTC

Elingasse 38160 WeizAustria

Phone: +43 (51707) 71417Mobile: +43 (664) 80117 71417

E-mail:[email protected]

siemens.com/transformers

mailto:[email protected]

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Transformer Technology Seminar What to consider at … · Transformer Technology Seminar ... • To ensure both parties having the same understanding of the contract, the ... operating