RQS circuit PowerPoint Presentation, PPT - DocSlides

RQS circuit PowerPoint Presentation, PPT - DocSlides

2016-10-31 41K 41 0 0

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Simulation results of Quench. . Antonopoulou Evangelia. June 2011. Thanks to E. Ravaioli. General Information – RQS circuit. Type. 600A. Imax. 600A. Converter. RPMBA. Magnet. MQS. # of m.. 4. EE. Yes. ID: 482805

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Presentations text content in RQS circuit

Slide1

RQS circuitSimulation results of Quench

Antonopoulou EvangeliaJune 2011

Thanks to E. Ravaioli

Slide2

General Information – RQS circuit

Type600AImax600AConverterRPMBAMagnetMQS# of m.4EEYes

2

Slide3

Powering subsector A12Circuit RQS.A12B2

Power Converter AttributesRcrowbar0.05ΩMain parameters R tot measured0.004010ΩL tot0.124 HInductance per aperture 0.031 HQuench Protection System Energy ExtractionDQEMCExtraction Resistance700 mΩParallel Protection Resistor per Magnet0.25 Ω

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Slide4

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Slide5

Improved Schematic-RQS circuit

(Main Circuit)

5

Power Converter

Crowbar

Magnets and Parallel Resistances

EE System

Resistance of the

Busbar

Simulation of the Switches

Earthing

point

Slide6

Latest Schematic-RQS circuit(1/2)

6

Thermal Model

Main Circuit

Slide7

Latest Schematic-RQS circuit(2/2)

7

Thermal Model

Electrical resistance

Thermal resistance

Thermal capacitance

Thermal resistance

of the insulation layer

Magnetic field

Inductance

Magnetic transfer function

Magnet 1

Magnet 2

Magnet 3

Magnet 4

Slide8

Crowbar

The system is based on a 50 m

Ω Power Resistance series back-to-back thyristors being fired at a given output voltage, and then providing a safe path for magnet current

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Slide9

Energy Extraction System

In all 600 A DC-current corrector circuits, the extraction facilities are inserted in series with the magnet chain. During normal operation the ex-traction breaker remains closed, herewith by-passing the dump resistor. In case of a fast power aboard or a quench of a magnet, the extraction breaker will be forced open, herewith switching the current to the dump -resistor. The extraction equipment is based on three individual, series-connected, high-speed, electro-mechanical

AC circuit breakers

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Slide10

Simulation of the Energy Extraction System

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Slide11

The resistance of the switches in the EE system

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Resistance of the switches:

Parabolic=2ms

exponential=11ms

Slide12

Snubber Capacitor

The electrical arc, between the breaker’s contacts, causes significant erosion of the contact surfaces. In the LHC 600 A EE systems the arcing time attains typically 7 ms at ultimate current leading to sufficient damage and required maintenance after just a few commutations. To minimize the arc influence and reduce the opening time, a capacitor bank is introduced across the breakers with the following characteristics: - The capacitor voltage rating shall exceed the peak extraction voltage of 420 V. - Internal inductance (Lesr < 80 nH) and resistance (Rs < 6 mΩ shall be low. - Gives a capacitor value between 0.14 and 1.4 mF. Experiments have shown that the optimized capacitor value is 0.8mF.

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Slide13

Simulation results of the influence of the snubber capacitor (1/3)

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Without the

snubber capacitor the arcing time attains 8ms

Slide14

Simulation results of the influence of the snubber capacitor (2/3)

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With the

snubber capacitor the opening time is reduced in 3ms

Slide15

Simulation results of the influence of the snubber capacitor (3/3)

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Slide16

Simulation of the switches’ opening

Slide17

Data of PM_Browser

Slide18

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Slide19

Current in the RQS circuit comparison with PR_Browser data

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Simulation: RQS.A34B2

PM_Browser

event:

091115-060853.220_RPMBA.UJ33.RQS.A34B2

Slide20

Current in the Power Converter

and the Crowbar

When the Power Converter is shutted down all the current pass by the crowbar until the discharge of the circuit.

20

Slide21

Voltage across the Crowbar

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Slide22

Current in the circuit

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Slide23

Current in the RQS circuit comparison with PR_Browser data

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Simulation: RQS.A23B1

PM_Browser event:091004-121213.580_RPMBA.UJ33.RQS.A23B1

Opening of the switch in the EE system

Shut down of the power converter

Slide24

Current of the magnets and

their parallel resistance

After the shut down of the power converter, current pass by the parallel resistances of the magnets in order to protect them.This current has the opposite direction of the current of the circuit.

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Slide25

Voltage drop across the magnets

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Slide26

Current in the EE system(1/2)

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Slide27

Current in the EE system(2/2)

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Slide28

Voltage in the Dump resistance

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Simulation: RQS.A23B1

PM_Browser

event:

091004-121213.580_RPMBA.UJ33.RQS.A23B1

Slide29

Electrical Resistance on the magnets

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Slide30

Electrical Resistance on the magnets

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Slide31

Temperature of the cable

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Slide32

Thermal Power dissipated in the magnet due to quench

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Slide33

Energy dissipated in the magnet due to quench

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Slide34

Calculation of τcircuit with 2 magnets (RQS.A34B2)

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Slide35

Calculation of τcircuit with 4 magnets (RQS.A34B2)

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Slide36

Further steps in due course

Investigation of the missing resistance in order to be more accurate in the simulation of the quenchesClarification of the misunderstanding test and comparison of the data of PM_Browser with my simulation

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Slide37

Thank you for your attention

Merci beaucoup pour votre attantionΕυχαριστώ για την προσοχή σας

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