Control, monitoring and safety aspects of electrical distribution in the Atlas experiment W.Iwanski...

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


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



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



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)



Gas roomCV room

Racks L1 &2

ESD4/1DX

UPS 600 kVA


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


EOD2/15

Racks L2

US15

EOD5/15A

ID racks

Muon racks

Control of Magnets


Cut by the PLC after 10 min(load shedding)

Cut by the DSS in case of emergency




Gas room

CV roomRacks L1 &2

ESD4/1DX

UPS 600 kVA


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


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…..


Cut by the DSS in case of emergency


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



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



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



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.



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



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



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.



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



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.


Control, monitoring and safety aspects of electrical distribution in the Atlas experiment W.Iwanski...

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