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EFDA Task WP08-HCD-01-02. Arc Detection Study. R. D’Inca – December, 4 th 2008. Outline. Objective Requirements Design IPP activities Methodology Next steps. Objective. “Development of a reliable arc detection system for ICRF heating on ITER”. Selected detectors:. SHAD SMAD
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EFDA Task WP08-HCD-01-02 Arc Detection Study R. D’Inca – December, 4th 2008
Outline • Objective • Requirements • Design • IPP activities • Methodology • Next steps
Objective “Development of a reliable arc detection system for ICRF heating on ITER” Selected detectors: • SHAD • SMAD • Optical detector • Guidar - Requirements analysis - Design - Test 3 associated tasks
Requirements Ref: Document ADS-01 Product Requirements Document - Nov 08 - R. D’Inca 1. Functional requirements The system has to detect arcs inside the ICRF system, in less than 5s, and to send a shutdown signal to the generator. 2. Safety requirements The probability of detection of an arc with high energy content is 100% The probability of detection of an arc with low energy content is 80% 3. Efficiency requirement The arc detection system cannot produce more than 5% of spurious detections
Requirements Ref: Document ADS-01 Product Requirements Document - Nov 08 - R. D’Inca 4. Environment of the arc detection system A. Characteristics of arcs B. Characteristics of the ICRF system C. Impact of Plasma D. Electromagnetic perturbations
Requirements Ref: Document ADS-01 Product Requirements Document - Nov 08 - R. D’Inca 4. Environment of the arc detection system 1. Impact on RF line characteristics: VSWR, Q, voltage/current profiles, S-Matrix of RF components 2. RF spectrum signature 3. Optical spectrum signature 4. Radar signature 5. Energy content A. Characteristics of arcs B. Characteristics of the ICRF system C. Impact of Plasma D. Electromagnetic perturbations Classification of arcs
Requirements Ref: Document ADS-01 Product Requirements Document - Nov 08 - R. D’Inca 4. Environment of the arc detection system Current classification 3 families of arcs: Type I: high voltage arcs Type II: multipactor induced arcs Type III: low voltage node arcs A. Characteristics of arcs B. Characteristics of the ICRF system C. Impact of Plasma D. Electromagnetic perturbations
Requirements Ref: Document ADS-01 Product Requirements Document - Nov 08 - R. D’Inca 4. Environment of the arc detection system Signature in frequency domain of type I arcs Current classification 3 families of arcs: Type I: high voltage arcs Type II: multipactor induced arcs Type III: low voltage node arcs A. Characteristics of arcs B. Characteristics of the ICRF system C. Impact of Plasma D. Electromagnetic perturbations
Requirements Ref: Document ADS-01 Product Requirements Document - Nov 08 - R. D’Inca 4. Environment of the arc detection system Current classification 3 families of arcs: Type I: high voltage arcs Type II: multipactor induced arcs Type III: low voltage node arcs A. Characteristics of arcs B. Characteristics of the ICRF system C. Impact of Plasma D. Electromagnetic perturbations
Requirements Ref: Document ADS-01 Product Requirements Document - Nov 08 - R. D’Inca 4. Environment of the arc detection system Signature in frequency domain of type II arcs Current classification 3 families of arcs: Type I: high voltage arcs Type II: multipactor induced arcs Type III: low voltage node arcs A. Characteristics of arcs B. Characteristics of the ICRF system C. Impact of Plasma D. Electromagnetic perturbations
Requirements Ref: Document ADS-01 Product Requirements Document - Nov 08 - R. D’Inca 4. Environment of the arc detection system Current classification 3 families of arcs: Type I: high voltage arcs Type II: multipactor induced arcs Type III: low voltage node arcs A. Characteristics of arcs B. Characteristics of the ICRF system C. Impact of Plasma D. Electromagnetic perturbations
Requirements Ref: Document ADS-01 Product Requirements Document - Nov 08 - R. D’Inca 4. Environment of the arc detection system Signature in frequency domain of type III arcs Current classification 3 families of arcs: Type I: high voltage arcs Type II: multipactor induced arcs Type III: low voltage node arcs A. Characteristics of arcs B. Characteristics of the ICRF system C. Impact of Plasma D. Electromagnetic perturbations
Requirements Ref: Document ADS-01 Product Requirements Document - Nov 08 - R. D’Inca 4. Environment of the arc detection system Characteristics to be precised: A. Characteristics of arcs B. Characteristics of the ICRF system C. Impact of Plasma D. Electromagnetic perturbations Geometry of the system Extension of the monitored area (vacuum lines/pressurized lines) RF frequency range RF properties of the line Noise level Multipactor Extrapolation from current facilities to ITER
Requirements Ref: Document ADS-01 Product Requirements Document - Nov 08 - R. D’Inca 4. Environment of the arc detection system The plasma has different perturbing effects to be quantified: A. Characteristics of arcs B. Characteristics of the ICRF system C. Impact of Plasma D. Electromagnetic perturbations L/H transition ELMs Generation of frequencies in the MHz range Arcs in the vacuum vessel RF wave coupling Light emitted by the plasma Change of boundary conditions
Requirements Ref: Document ADS-01 Product Requirements Document - Nov 08 - R. D’Inca 4. Environment of the arc detection system Signature in frequency domain of type III arcs The plasma has different perturbing effects to be quantified: A. Characteristics of arcs B. Characteristics of the ICRF system C. Impact of Plasma D. Electromagnetic perturbations L/H transition ELMs Generation of frequencies in the MHz range Arcs in the vacuum vessel RF wave coupling Light emitted by the plasma Change of boundary conditions
Requirements Ref: Document ADS-01 Product Requirements Document - Nov 08 - R. D’Inca 4. Environment of the arc detection system The plasma has different perturbing effects to be quantified: A. Characteristics of arcs B. Characteristics of the ICRF system C. Impact of Plasma D. Electromagnetic perturbations L/H transition ELMs Generation of frequencies in the MHz range Arcs in the vacuum vessel RF wave coupling Light emitted by the plasma Change of boundary conditions
Requirements Ref: Document ADS-01 Product Requirements Document - Nov 08 - R. D’Inca 4. Environment of the arc detection system Electromagnetic Compatibility A. Characteristics of arcs B. Characteristics of the ICRF system C. Impact of Plasma D. Electromagnetic perturbations Noise induced by other electronic devices Magnetic field
Requirements Ref: Document ADS-01 Product Requirements Document - Nov 08 - R. D’Inca 4. Interfaces Mechanical, electrical 5. Operational constraints Lifetime, life profile 6. Maintenance 7. Costs
System Design Ref: Document ADS-02 System Design Document - Nov 08 - R. D’Inca No detector has proven its respect of all requirements: SHAD: spurious detections, doubt on detections of low-voltage node arcs SMAD: dedicated to specific components Optical detector: difficulty to detect arcs on the antennas GUIDAR: low maturity level for ICRF application => The Arc Detection System will probably be based on an architecture of different detectors
System Design Ref: Document ADS-02 System Design Document - Nov 08 - R. D’Inca Compliance matrix:
IPP Activities - Characterization of arcs: * in time and frequency domain * optical properties (to discuss) - Optimization of SHAD system: analysis of spurious frequencies - Development of the interface between RF coax and GUIDAR - Test of detectors
IPP Activities 2 complementary facilities MXP – Manipulator eXPeriment AUG – ASDEX Upgrade 1) Characterization of arcs 2) Test of arc detectors 3) Characterization of arcs emitted by the plasma 1) Characterization of arcs 2) Test of arc detectors Production of arcs under controlled conditions: geometry, DC magnetic field, power injected Fast Acquisition System: 3x4 channels at up to 500MS/s
MXP - Manipulator eXPeriment Testbench dedicated to the production of arcs with power between 1kW and 700kW CAMAC Tuner #1 Tuner #2 Magnetic coils Vacuum vessel PAL camera Video G Decoupler Helium FAS SHAD Filter Reference: [MXP1] – Experiment description – 1/12/07 – R. D’Inca
A few words on Methodology • A shared and centralized documentation: • Requirements, design, bibliography • Visibility on planning • Regular informal reporting
Next steps • Identification by each team member of: • its milestones: design, production, test, deliverables • needs in data, testbench sessions