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Control, monitoring and safety aspects of electrical distribution in the Atlas experiment
W.Iwanski PH/ESE-BE
W.Iwanski PH/ESE-BE 2
Outline
Overview of electrical supply in Atlas Evolution of the UPS system Controlling and monitoring infrastructure Monitoring applications Safety of racks’ electronics Conclusions
TWEPP conference, Vienna, 28/09/2011
W.Iwanski PH/ESE-BE 3TWEPP conference, Vienna, 28/09/2011
W.Iwanski PH/ESE-BE 4
Repartition of power among different Atlas sub-systems
Atlas equipment consumes in total ~ 7 MW of the Regular, UPS and Diesel power during normal operation
CryogenicsAtlas racksCoolingVentilationGeneral servicesMagnet
Regular power: 6.6 MW Diesel power: 0.3
MW UPS power: 0.25 MW
6.6
0.30.25
TWEPP conference, Vienna, 28/09/2011
W.Iwanski PH/ESE-BE 5
Characteristics of the UPS system of Atlas
UPS power is not cut by the AUG but can be cut by the DSS Primary function of the UPS is to assure power availability during a power cut UPS is backed up by Diesel generators In case a Diesel generator fails, a PLC manages shedding of the SDX1 UPS load
according to the following profile: 2 h of power is guaranteed for critical users 10 min of power is guaranteed for less critical users
TWEPP conference, Vienna, 28/09/2011
W.Iwanski PH/ESE-BE 6
Gas roomCV room
Racks L1 &2
ESD4/1DX
UPS 600 kVA
Atlas UPS DieselMains 400V
EOD1/1DX
EOD2/1DX
RacksSDX1
SH1Cryo
SCX1ACR
EOD1/15A
EOD3/15A
Cryo ctrl room Control of Magnets
EOD4/15A EOD2/15A
SDX1
USA15
ESD3/15
UPS 160 kVA
Meyrin DieselMains 400V
EOD2/15
Racks L2
US15
Evolution of the UPS system in Atlas (1)
Cut by the PLC after 10 min(load shedding)
TWEPP conference, Vienna, 28/09/2011
W.Iwanski PH/ESE-BE 7
Gas roomCV room
Racks L1 &2
ESD4/1DX
UPS 600 kVA
Atlas UPS DieselMains 400V
EOD1/1DX
EOD2/1DX
RacksSDX1
SH1Cryo
SCX1ACR
EOD1/15A
EOD3/15A
Cryo ctrl room
EOD4/15A EOD2/15A
SDX1
USA15
ESD3/15
UPS 160 kVA
Meyrin DieselMains 400V
EOD2/15
Racks L2
US15
EOD5/15A
ID racks
Muon racks
Control of Magnets
Evolution of the UPS system in Atlas (2)
Cut by the PLC after 10 min(load shedding)
Cut by the DSS in case of emergency
TWEPP conference, Vienna, 28/09/2011
W.Iwanski PH/ESE-BE 8
Evolution of the UPS system in Atlas (3)
Gas room
CV roomRacks L1 &2
ESD4/1DX
UPS 600 kVA
Atlas UPS DieselMains 400V
EOD1/1DX
EOD2/1DX
RacksSDX1
SH1Cryo
SCX1ACR
EOD1/15A
EOD3/15A
Cryo ctrl room
EOD4/15A
EOD2/15A
SDX1
USA15
ESD3/15
UPS 160 kVA
Meyrin DieselMains 400V
EOD2/15
Racks L2
US15
EOD5/15A
ID racks
Muon racks
UPS 80 kVA
EOD6/15A
Control of Magnets
EOD7/15A
Load shedding turned out to be impractical and finally was given up…..
TWEPP conference, Vienna, 28/09/2011
Cut by the DSS in case of emergency
W.Iwanski PH/ESE-BE 9
Electronic racks of Atlas
More than 450 racks host Atlas electronics in 4 different zones, some of them are inaccessible during normal LHC operation; all types of power are used to feed the equipment
Regular power fed racks: 336
UPS fed racks: 55
Mixed power (Regular + UPS) fed racks:38
Diesel fed racks: 29
TWEPP conference, Vienna, 28/09/2011
W.Iwanski PH/ESE-BE 10
Basic infrastructure for controlling and monitoring
Rack’s supplying box Concentrating PLC
Expert panel
Powering switchboards
Concentrating PLC makes state of the system available to the supervising database (CCC) and user application (DCS)
Concentrating PLC provides platform to communicate with the local PLCs in supplying boxes or powering switchboards
Local PLCs execute ON/OFF commands on powering breakers and monitor their state (opened/closed/tripped)
LHC Control Room (CCC)
Atlas Control Room
TWEPP conference, Vienna, 28/09/2011
W.Iwanski PH/ESE-BE 11
Control and monitoring of the racks’ poweringRegular supply UPS” supply
Expert panel ON/OFF ON
DCS (Rack Control) ON/OFF ON
DSS OFF OFF
Apr-08 Jul-08 Oct-08 Feb-09 May-09 Aug-09 Dec-09 Mar-10 Jun-10 Sep-10 Jan-11 Apr-11 Jul-11 Nov-11 Feb-120
1
2
3 Switching OFF in rack Y.24-14.A1 (Regular power)
DSSAll
Type of the control depends on Master
Most of the switch-OFF operations comes from DSS, rarely from an operator, sometimes due to atmospheric conditions (perturbations or power cut)
When power comes back after a cut, all racks stay OFF and need to be re-powered by an operator
TWEPP conference, Vienna, 28/09/2011
W.Iwanski PH/ESE-BE 12
Control of supply of the TDAQ computers
Powering of 100 racks with up to 31 TDAQ computers in each requires special attention:
Two independent 3-phase powering lines per rack
NTC thermistors on each phase to reduce the inrush current
Each line individually controlled and monitored
PLC-controlled timer disallows immediate back-to-back power re-cycling on the same powering line
Applied solution proved to be reliable and sufficient one.
TWEPP conference, Vienna, 28/09/2011
W.Iwanski PH/ESE-BE 13
Electricity Distribution Monitor
Simple but very reliable system, used for monitoring of the electrical infrastructure
Shows status of all electrical supplying cabinets important for Atlas operation
System based on voltage presence sensors being read by the ELMB card interfaced to a local DCS station
Application developed by Atlas and integrated with the global monitoring environment of the experiment
TWEPP conference, Vienna, 28/09/2011
W.Iwanski PH/ESE-BE 14
Quality of power supply
Event on powering network caused by a turning ON of the SVC filter featuring a glitch down to 50 V and 80 V voltage spike
In general, powering network at Cern is clean albeit occasionally perturbed by the atmospheric storms
Atlas like other experiments has Filters (SVC + TCR) on the Machine network. They, when working, bring a lot of positives :
compensation of reactive power reduction of harmonic distortions voltage stability
… but when being turned ON, produce disturbances. Their turning ON is coordinated with experiments by CCC
TWEPP conference, Vienna, 28/09/2011
W.Iwanski PH/ESE-BE 15
Power Quality Monitor System monitors state of filters in
the experimental zone as well as on the LHC loop
System spies on alarms from the analyzers recording events happening on the 18 kV Machine and GS LHC loop networks
System is ready to monitor signals from local analyzers to be connected to register events on selected 400 V branches
System launches acknowledgeable alarms on the Alarm screen in the Control Room whenever supervised equipment gets activated
Applications developed for the moment for Atlas and Alice experiments.
TWEPP conference, Vienna, 28/09/2011
W.Iwanski PH/ESE-BE 16
Safety of the rack’s electronic equipment Wherever there is an electricity there is a certain
risk of fire. Racks hosting an electronic equipment and having a vertical cooling have hardware interlocks cutting the power whenever the temperature or smoke sensors get active.
As an additional protection against fire Atlas developed a control and monitoring system for extinguishers with the liquid CO2 installed in selected racks with the high power or unique electronics:
• Release of the liquid CO2 to a closed volume of the rack either by pressing a button or when the temperature and smoke conditions are met
• Veto from the rack’s back door being opened
• Global enable for each zone from the Atlas Control Room
• State of all sensors fully monitored by the Minimax System application integrated with the global monitoring environment of the experiment
Triggering condition Press button
Back door’s veto
Global enable
Monitoring of all sensors
Atlas Smoke & temperature Yes Yes Yes Yes
CMS Smoke & temperature Yes No Yes No
LHCb Smoke & temperature No No Yes No
Comparison of the Minimax Systems developed in the LHC experiments
TWEPP conference, Vienna, 28/09/2011
W.Iwanski PH/ESE-BE 17
Conclusions
Atlas being an experiment built from scratch, fully profits from a modern electrical infrastructure building a robust monitoring and controlling systems around it.
Despite being in operation since several years, the electrical infrastructure is still evolving implying adjustments in the monitoring and control systems. Imperfections of the implementations are uncovered by major events.
Applications like the Electricity Monitor or the Power Quality Monitor or the Minimax System developed in Atlas bring an added value to the monitoring environment developed typically in other experiments.
TWEPP conference, Vienna, 28/09/2011