Transcript electrical distribution

LBDS
Environmental Aspects
EMC, radiation, UPS…
Etienne CARLIER
AB/BT/EC
Etienne CARLIER, LBDS Audit, 28/01/2008
Outline
LBDS
• Electrical Distribution
– Architecture
– Protections
• EMC
– Emission
– Immunity
– Shielding
• Radiation
Etienne CARLIER, LBDS Audit, 28/01/2008
LBDS
Electrical Distribution
Architecture
• The LBDS kicker electrical distribution is based on a
combination of
– Normal supply for power components (power supplies…), and
– Uninterruptible supply for control components (SCSS, BETS and
TSDS).
• High voltage and low voltage power supplies are conform
with the CE regulations.
 Normal power distribution system instabilities will not disturb
operation
 A pulse to pulse reproducibility of +/- 0.1% is guaranteed for a +/-10%
mains variation, a 2% asymmetry between phases and a 3% variation
of the mains frequency.
• Surveillance of the electrical distribution system is included in
the SCSS
Etienne CARLIER, LBDS Audit, 28/01/2008
LBDS
Normal / Uninterruptible Supply Failure
BETS
BETS
Reference
UPS
Kicker
Power Supplies
Normal supply
BETS
Interlock
UPS
Active fail-safe redundant logic
Normal supply failure
Uninterruptible supply (UPS) failure
Detection delay of a normal supply power cut
based on beam energy tracking interlock
0,350
0,300
0,250
Sec
 BETS reaction time is deterministic
 Extraction trajectories are guaranteed
within operational limits through the beam
dump energy tracking interlock
 Detection delay depends of the sensitivity of
the BETS interlock windows, generator
impedance, HV power supply hold-up time,
machine mode and energy…
Dump
Request
0,200
0,150
0,100
0,050
0,000
450
1450
2450
3450
4450
5450
6450
GeV
 BETS reaction time is not deterministic
 Detection delay depends of impedance of electronics circuits, failure sequence of microcontroller, low voltage power supply hold-up time….
 BETS will fail due to the absence of power and issue a dump request (fail-safe logic)
 A detection of the UPS failure faster than 80ms is achieved through a continuous surveillance
of the UPS voltage
Etienne CARLIER, LBDS Audit, 28/01/2008
Normal / Uninterruptible Supply Failure
TSDS
LBDS
Dump Request
Receiver
Abort Gap
Synchronization
Active fail safe logic
Trigger
Power
Fan out
Trigger
UPS
Passive fault tolerant redundant logic
HV
Generator
Dump request distribution uses the “domino effect”
Energy required to distribute the dump request up to the kicker HV generator is
–
–
–
Pre-stored within capacitor at each stage of the triggering chain,
Used to trigger the next stage, and
Checked before a beam permit signal is issued
Normal Supply Failure
 Uninterruptible supplies guarantee the correct propagation of the dump request up to the
HV generator.
Uninterruptible Supply Failure (UPS)
 Detected at the fail safe logic stages (“Client Interface”)
 Propagation of the dump request to the HV generator relies on the ability of each
passive stage of the triggering chain to maintain their output power capabilities in a
correct operational windows during at least the 100 s following the detection delay,
 An additional asynchronous beam dump will be triggered through a RTD unit 100 s
after the detection delay.
Etienne CARLIER, LBDS Audit, 28/01/2008
Electro-Magnetic Compatibility
LBDS
General
Kicker = Fast Pulsed Magnet
Fast Transient
[s]
• Ready state
High Current
[kA]
Pulse Period +
Duration
Low Impedance
[H & m or ]
: 99,99999….% of the time (Pulse Period)
– Immunity to external electromagnetic perturbations
• Pulse state
: 0.00001… % of the time (Pulse Duration)
– Emission of electromagnetic perturbations
Etienne CARLIER, LBDS Audit, 28/01/2008
Layout
LBDS
Electronic
High
Voltage
Generator
Etienne CARLIER, LBDS Audit, 28/01/2008
Magnet
Coaxial
Transmission Line
LBDS
Assumptions
• EMC perturbations issued by kicker systems are mainly in
the High Frequency domain and are generated only during
the “Pulse State”.
• Components used in kicker systems and connected to the
power distribution systems (mainly high voltage and low
voltage power supplies) are conforming with the CE
regulations and with the IEC norms for EMC emission &
immunity and for Safety:
– IEC 61000-3 / EN 50081-1 for EMC emission,
– IEC 61000-6 / EN 50082-2 for EMC immunity, and with
– EN 61010
for safety.
• No specific measures implemented for immunity and
emission through the connections to the mains networks
(Normal and Uninterruptible).
• No sensitivity to Low Frequency EMC perturbations is
expected.
Etienne CARLIER, LBDS Audit, 28/01/2008
Operational Parameters
LBDS
* Value rated per system
Extraction Kickers
[MKD]
Dilution
Kickers
[MKBH & V]
Operational Range
450 GeV  7TeV
450 GeV  7TeV
Number of generators / system
15
Current Pulse Rise Time
2.8 s
Current Pulse Duration
Max. Switched Power *
>100 s
(1.8 ms)
16 kJ
Max. Peak Current *
270 kA
Max. dI/dt *
96 kA/s
Signal Spectrum
10 kHz 
300 kHz
0.05 m
4 [H]
6 [V]
17.6 s [H]
33.7 s [V]
>100 s
(0.5 ms)
10 kJ [H]
18 kJ [V]
100 kA [H]
150 kA [V]
5.5 kA/s [H]
4.7 kA/s [V]
13.8 kHz [H]
12.5 kHz [V]
0.3 m [H]
0.2 m [V]
Cable Return Resistance *
Etienne CARLIER, LBDS Audit, 28/01/2008
LBDS
•
•
•
•
•
•
•
•
•
•
•
Interconnections
Electrical distribution
Computer network
Machine timing system
Machine protection system
Access system
Beam instrumentation
Radio-frequency
Power converter
Vacuum system
Cooling
…
 A lot of possibilities for EMC coupling !!!
Etienne CARLIER, LBDS Audit, 28/01/2008
LBDS
Interconnections (cont.)
•
•
•
•
•
•
Electrical distribution
Computer network
Machine slow timing system
Machine protection system
Access system
Beam instrumentation
•
•
•
•
Radio-frequency/prepulse
Power converter
Vacuum system
…
TN-S (3PH + N + E)
???
Common mode
Fibre optics + opto-coupler
Isolated Floating contact
Common mode (PU) + Isolated blocking
oscillator (Trigger)
Fibre optics
Fibre optics
Isolated Floating contact
 Try to “isolate” as much as possible interconnections
between systems
Etienne CARLIER, LBDS Audit, 28/01/2008
LBDS
Perturbations
Immunity
• Kicker systems within the UA will be sensible during the
“Ready state” to electromagnetic fields (if any) generated by
other equipment due to ground loops.
– Ground loops in the vertical plane exist and are composed by the high
voltage generator, the transmission line, the magnet and the earth
common mode impedance between RA & UA.
– No possibilities to “physically” reduce these loops (…integration
issues) .We have to live with them and act on the electromagnetic field
sources (if any).
• Immunity of trigger (re-trigger) systems to external
perturbations has to be guaranteed (UA63  UA67).
– Use of shielded cables and differential transmission for re-trigger
signals.
– Use of low impedance (50 ) coaxial lines for trigger signals.
– Possibility to shield cable ladders in order to increase effectiveness of
the cable ladders protection against external perturbations.
Etienne CARLIER, LBDS Audit, 28/01/2008
LBDS
Perturbations
Emission
• Generation of common mode voltages across RA & UA
grounds / earths by the coaxial transmission lines during
“Pulse State”:
– Transmission lines are composed of a set of parallel coaxial cables
(impedance reduction),
– During the current pulse, a voltage difference is issued between both
ends of the transmission lines due to the transfer impedance of the
coaxial cable screen and to the cable’s screens skin effect for the
return current,
– This difference of voltage generates a common mode voltage between
RA and UA grounds / earths. This voltage is proportional to the current
in the transmission line and to the ratio of the cable transfer
impedance and the earth common mode impedance.
• “Ground jumps” across RA & UA during “Pulse State”:
– During a current pulse, part of the current (typ. 0,01% of Imax) will
flow through the earth circuit and generate “ground jumps” between
RA and UA proportional to the earth common mode impedance
Etienne CARLIER, LBDS Audit, 28/01/2008
Perturbations:
LBDS
Emission (cont.)
Cable ladders
[UA & RA]
Transmission
Line
Cable ducts
[UA  RA]
Radiated Emission
– The difference of current between inner
and outer conductors of the coaxial
transmission lines generate an
electromagnetic field around the
transmission line itself
Etienne CARLIER, LBDS Audit, 28/01/2008
LBDS
Perturbations
Emission (cont.)
• Equipment sharing the same earths in the UA & RA will be
affected by Conducted Emission perturbations during kicker
“Pulse State”:
– Differential measurements will / can guarantee signal integrity.
• Cables crossing / passing near kicker transmission lines
between UA and RA will be affected by Radiated Emission
perturbations during “Pulse State”:
– Good cable shielding will / can protect the signals
• Levels for Conducted Emission and Radiated Emission are
difficult to quantify at this stage:
– Measurements from prototype installations exist but coupling effects
between generators will not be negligible
– Quality of the earth system in the UA, in the RA and between UA &
RA has not yet been quantified. The Conducted and Radiated
Emission levels depend partially on this parameter.
Etienne CARLIER, LBDS Audit, 28/01/2008
Protection
LBDS
Grounding and Shielding
Extension of the equipotential up to the front
of the rack through low impedance
mechanical solution
Use
EUROPA
crates
with
ALODINE 1200 surface treatment
for electronic hardware
Grounding through an
equipotential environment in
the UA
Measure cables properly shielded in the cable’s
ducts (parallel to the transmission lines)
between UA & RA with a simple steel tube
Etienne CARLIER, LBDS Audit, 28/01/2008
LBDS
Radiation
• Electronics for the control of the LBDS kickers is located in
the UA
– 80% digital  Most critical (single event corruption)
– 20% analogue
• Electronic is always located below the level of the cable ducts
between UA / RA  Passive shielding with concrete
• No special protection implemented
– No worries for electronics in the UA after the test in TCC2 in
1999/2000 before decision
• For the SCSS the situation is safe  a failure in one of the
“SAFE” component will automatically issue a dump request.
• Redundancy helps. Probability to have a simultaneous
“single event” affecting redundant components is low…
Etienne CARLIER, LBDS Audit, 28/01/2008