Transcript Switch between 1 or 2 capacitors - Indico

Overview of the CLIQ Units
Project
Knud Dahlerup-Petersen, Félix Rodríguez-Mateos
TE-MPE Technical Meeting
CERN, April 16 2015
Outline
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Introduction and general aspects
• Choice of main components
• Safety aspects
• The mini-Review and principal outcome
• A glance to the future of CLIQ
• The Team
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Introduction and general aspects
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Several units of CLIQ power supplies
have been manufactured by the MSC
Group over the last years and used at
CERN for testing of different magnets in
SM18
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We do not present here the “ad-hoc”
design of those units
This previous design has given the
needed flexibility to optimize parameters
as capacity, voltage/current, frequency
and dumping time constant
A new hybrid protection system for
high-field superconducting
magnets
E Ravaioli, V I Datskov, G Kirby, H H J
ten Kate, and A P Verweij
There is now a request from MSC to
the MPE Group to produce 3 units, 2
of which will be sent to FNAL by the
end of May’15. The third one will
serve as spare
If successful, this project will continue
with more prototypes and ultimately a
production of series for Hi-Lumi upgrade
magnets
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Some facts and boundary conditions
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The EE Section got the mandate in early February 2015
Delivery for end of May 2015
Choice of components was determined by the very short delivery time
Resource organization was affected by the short lead time, with
involvement of an important fraction of the section members
Experience from the DQHDS is an important feature, although being of a
different nature (only discharge)
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Choice of main components
Capacitors (1)
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The CLIQ power unit is not only a supply, it is an energy exchanger
This will lead to the characteristic ringing, which is being increasingly
damped by the resistances in the circuit, mainly the rapidly increasing
resistance of the quenching coil, but also by the series-equivalent
resistance of the capacitor bank and cable leads
The ringing leads to both positive and negative voltages on the storage
capacitors within one current direction
Typical CLIQ discharge (Emmanuele)
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Capacitors (2): selection
The storage capacitor bank for CLIQ must, according to
considerations, be of bipolar type
above
Further requirements
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Low internal series-equivalent resistance
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High capacitance density
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Minimum bus bar work for connection
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Switch between 1 or 2 capacitors
Selected type
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Self-healing, dry type, metallized polypropylene
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Data: 500 V, 2 x 40 mF, 2 x 44 kg (from LHC QF/QD snubber
capacitor spares)
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With over-charge protection and over-pressure indication
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Stored energy: 10 kJ
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Charging circuit
The LHC 3-step type of charger is replaced by a 100
mA constant-current charger of commercial origin tailored to our application. Full charging time around
400 s.
Charging voltage shall be adjustable in steps of 50 V
(manual commutation, up/down).
Charging from 110 V, 60 Hz as from 240 V, 50 Hz.
Capacitor voltage and charging current shall be
displayed as well as the end of charging state.
16/04/2015
MPE Technical Meeting
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Thyristors (1)
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Discharge characteristics of bi-directional nature (discharge / recharge
currents) => semiconductor switches in a bi-directional arrangement have
been chosen
Good experience from the LHC quench discharge heater units with the
use of thyristor switches => decision to keep the thyristors option for the
CLIQ units
Thyristors will be used in both directions in order to assure a ‘certain
separation’ of the main magnet powering circuit from the heater circuit
outside the provoked coupling period
The two opposite thyristors shall be fired simultaneously for 0.5 s. No trigger
redundancy in each unit is considered necessary
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Thyristors (2): selection
Two candidate thyristors have been considered:
1. Single Thyristor used for fast opening pulse to LHC main circuit energy
extraction switches (BCM). To be doubled
2. Bi-directional Thyristor for energy management. Approved by ABB for
the CLIQ application. Two thyristors in one wafer
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The thyristor firing shall be provoked through application of a train of pulses,
from a 12 kHz generator through pulse transformers.
Discharge current shall be measured by adequate AC current transformer
(6kA peak, 10-3 accuracy).
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Safety aspects
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A main breaker (or a switch + fuse), accessible on the outside panels of the CLIQ
unit, shall assure not only interruption of the input power but equally switch-in a
bank of discharge resistors which will assure an automatic ‘internal’ discharge of
the complete capacitor bank. The total discharge time shall be 1 minute maximum.
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In addition to a clear indication of the actual charging voltage/current (analog
voltmeter or galvanometer per capacitor), a visible indicator shall show safe
conditions (<40V).
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After re-powering from the mains input, there shall be no automatic re-charging of
the capacitor bank (system is latched). Charging shall be initiated manually.
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After a discharge the system is automatically latched. Recharging only by manual
activation.
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Activation of the equipment stop button shall initiate an internal discharge of the
capacitors
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For changing the capacitance value (switch between 1 or 2 capacitors),
possibilities should be studied that do not imply opening of the rack (lockable
switch that can only be activated after discharge of the capacitors)
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The mini-Review and principal
outcome
Objectives
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Validation of the implementation of the
concept
• Coherence of the choices with respect to the
established functionalities
• Correctness with integration and
implementation according to the electrical
standards applicable
• Safety aspects
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Panel
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Jean-Paul Burnet, TE/EPC
• Alexandr Erokhin, TE/MPE
• José Carlos Gascón, DGS-SEE-XP
• Christian Giloux, TE/MSC
• Andrzej Siemko, TE/MPE (ex-officio)
• Yves Thurel, TE/EPC
The mini-Review took place on April 8, 2015
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Agenda
1. Scope and objectives of the review
Félix Rodríguez Mateos
10’
2. Introduction to the CLIQ protection
method
Emmanuele Ravaioli
15’
3. General aspects of the design, choice Knud Dahlerup-Petersen
of components and safety issues
15’
4. Details of the design
Joaquim Mourao
30’
5. Integration and implementation
Mathieu Favre
15’
6. Discussion and questions from the
panel
All
30’
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Recommendations (1)
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Components
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use the higher rated ABB thyristors which give larger margin in all
parameters
set 0.5s for the duration of the train of pulses
discharge resistors should not to be mounted on a PCB, 20 resistors
in series should not be used
thyristor firing circuit to be completed (paying attention to
magnetization of the pulse transformers)
use an AC current transformer instead of a LEM for discharge current
measurement
qualify the AC/DC converter in terms of EMC or use qualified material
16/04/2015
MPE Technical Meeting
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Recommendations (2)
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Safety
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maximum discharge time should be 1 min
use a switch that a) triggers internal discharge, b) short-circuits
capacitors and c) allows opening the cubicles (if required)
use a properly rated circuit breaker for ON/OFF and not a
“sectionneur”, or add a fuse
earthing issue: for such mobile units as the ones under discussion the
earth connection given through the powering mains is enough
no need for special screws, idem for internal plastic covers
install galvanometers to show the charge/discharge of each capacitor
Project Management
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prepare test programme well in advance
prepare documentation for the future users
structure the project (mandate, functional specifications, technical
specifications, planning, responsibilities, etc)
16/04/2015
MPE Technical Meeting
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A glance to the future of CLIQ
Near future plan for protecting magnets
with CLIQ
LHC-high luminosity upgrade
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QXF is the inner triplet large
quadrupole strings of magnets
either side of the ATLAS and
CMS.
 Model testing in Fermi-lab (two
units plus spare)
 Model testing in CERN (Two
units plus spare)
 First long magnet prototype
test in BNL (Two units plus
spare)
 Production of 32 + spares
units for LHC-HL, assuming
two units per magnet.
Courtesy Glyn Kirby
Longer term possibilities for use in LHCHL upgrade
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CERN
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Orbit correctors for LHC-HL: Twin aperture independently powered dipole
MQY for LHC-HL with pushed performance for the upgrade. Currently being
tested in SM 18 at CERN.
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LHC: Main dipole will be tested at CERN in SM18 in the following months in
view for rapid repair of LHC systems
Outside CERN
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KEK Japan: D1, LHC-HL Single aperture standalone dipoles requiring 4 units
+ spares
CEA France: Q4 Twin aperture quadrupoles ~ 16 units + spares
GSI: they are investigating for use with their magnet systems
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Each magnet would need 4 units
Further future
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16 Tesla hybrid FCC models
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block design & cos-theta design could benefit from CLIQ
CCT design (canted cosine theta) may rely on CLIQ; LBNL have requested two
units for future testing of their 16 Tesla CCT magnet.
The team
Members of the team in MPE
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Knud Dahlerup-Petersen
Arnie Dinius
Mathieu Favre
Joaquim Mourao
Bozhidar Panev
Emmanuele Ravaioli
Felix Rodriguez Mateos
Other contributors:
Gert Jan Coelingh
Alexandr Erokhin
Yan Bastian
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