lhc ups systems and configurations: changes during the ls1 v. chareyre / en-el lhc beam operation...

LHC UPS Systems and Configurations: Changes during the LS1

V. Chareyre / EN-EL

LHC Beam Operation Committee

11 February 2014

EDMS No. 13549771 11/02/2014

Outline

UPS systems and replacement project during LS1 New configuration in the alcoves and LHC odd points New configuration in LHC even points New powering interlock rules EMC considerations Conclusion

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LHC Beam Operation CommitteeChanges in UPS Configurations

UPS Systems for the LHC

Critical equipment around the LHC powered by Uninterruptible Power Supply (UPS) systems QPS (Quench Protection System), Beam Dump System, Beam Loss Monitor, etc. Machine

Protection Cryogenics and vacuum control systems, power converters auxiliary circuits, etc. Machine

Availability

UPS principle Continues to provide power to critical loadswhenever the input power fails for the time given by the backup battery

Nominal conditions:load powered via the double conversion path

Input source failure:the load remains supplied by the inverter using the battery stored energy

Load automatically transferred to the bypass line in case of: Internal UPS failure End of battery autonomy (requires bypass AC source available) Short-circuit or overload on the downstream distribution (unlikely)

Fully automatic, load transfers < 1 ms 3

Rectifier

Inverter

StaticSwitches

NormalAC source

BypassAC source

Power to load

Battery


EDMS No. 1354977 11/02/2014

Rectifier

Inverter

StaticSwitches

NormalAC source

BypassAC source

Power to load

Battery

LHC UPS Systems Replacement Project

Replacement of the existing APC Silcon UPS systems during the LS1(see EDMS 1151991)

Project motivations: Improve the reliability Decrease the failure rate Minimize LHC run time losses

Change of UPS system topology: come back to the conventional double conversion UPS topology (with output isolation transformer)

4

Delta converter

Main converter

NormalAC source

Bypass

Power to load

Battery

StaticSwitches

Delta Transformer

Delta

Conversion

Double

Conversion

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Basic Requirement for the QPS

Basic requirement for a safe powering: 2 independent power paths and protected by upstream UPS systems

So-called F3 and F4 power lines distributed all along the tunnel QPS redundant equipment connected to F4

5

EOD F3 EOD F4

Distribution Line F3


- QPS1- CRG- VSC- BLM

- QPS2

EDMS No. 1354977 11/02/2014


UPS Configurations before the LS1: Alcoves (REs) and Odd Points

Basic requirement: 2 independent power paths and protected by upstream UPS systems

No link between both UPS units

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EOD F3 EOD F4




- QPS2

EBD Normal Network

UPS F3 UPS F4

Output UPS power protected

UPSs interfaced with the Powering Interlock Controller (PIC): Magnet powering stopped when loosing one UPS

EDMS No. 1354977 11/02/2014


EOD F3 EOD F4



UPS F3


- QPS2

UPS F4

UPS Backup

EBD Normal Network

New UPS Configurations in the Alcoves (REs) and Odd Points

3rd UPS (UPS backup) poweringthe bypass of both UPS F3 and UPS F4 = Stand-by redundancy

‘Natural’ redundancy:no communication busbetween the 3 UPS units

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Output UPS power protected

DistributionUnchanged

EDMS No. 1354977 11/02/2014


EOD F3 EOD F4



UPS F3


- QPS2

UPS F4

UPS Backup

EBD Normal Network

Tolerance to the First Failure

Example: UPS F3 internal failure UPS F3 transfers to bypass instantaneously UPS backup takes over the F3 load 2 power paths still protected After a failure, we come back to

the same situation as today(but with conventional UPS systems!)

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Output UPS power protectedOutput UPS power NOT protected

Failure of a second UPS in the same zone will stop the magnet powering (PIC triggered)

EDMS No. 1354977 11/02/2014


UPS Configurations in LHC Even Points (Before 2009)

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2 parallel-redundant UPS systems in:

UA (IP left side) US UA (IP right side)

Canalis in UA (F3)

UA (left)


- QPS1- CRG- VSC- BLM LHC Tunnel

US

EDMS No. 1354977 11/02/2014


UPS Configurations in LHC Even Points: before LS1

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Redundant QPS equipment powered from the UPS system located in the adjacent zone

F3 and F4 lines always powered from 2 different redundant UPS configurations (one in US, one in UA)

Allowed to preserve parallel-redundant UPS systems in UAs and USs

Was already tolerant to the first UPS failure (in each zone)

Canalis in UA (F3)

Racks QPS2 in UA (F4)

- QPS2

UA (left)




- QPS2

LHC Tunnel

US

EDMS No. 1354977 11/02/2014


New UPS Configurations in LHC Even Points

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Distribution remains unchanged Standby redundancy applied in UAs

and USs F3 and F4 lines still powered from 2

different redundant UPS configurations (one in US, one in UA)

Canalis in UA (F3)


- QPS2

UA (left)




- QPS2

LHC Tunnel

US

EDMS No. 1354977 11/02/2014


Tolerance to the First Failure (in each Zone)

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Example: failure of the first UPS in UA

Transfers to bypass instantaneously UPS backup takes over full load in

UA Redundant power paths still

protected Failure of one UPS in the adjacent

zone (US in this case) is allowed Failure of 2 UPS units in the same

zone will stop the magnet powering (PIC triggered)

Canalis in UA (F3)


- QPS2

UA (left)




- QPS2

LHC Tunnel

US

EDMS No. 1354977 11/02/2014


New Powering Interlock Rules

One single UPS failure = 2 power paths still protected = No PIC triggered

New rules: Magnet powering can continue upon one single UPS failure Machine can start with 2 UPS systems out of 3 in the alcoves and LHC odd points Machine can start with one UPS system out of 2 in the UA and US zones

New UPS configurations allows to wait for the next stop for repairing an UPS failure

Gives us more time for preparing and optimizing the intervention

UPS redundancy restored (and improved) Increases availability for all users, including EN-EL for fault repairs

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New UPS Systems – EMC Considerations

APC Silcon UPS systemswell-known to produce noise at 8 kHz

High frequency noise caused byswitching transistors (IGBTs) for creatingthe sine wave at the output

Switching frequencies varies according tothe UPS manufacturer and the design

New UPS specified according to applicable standards (IEC-62040-2) With the objective of attenuating perturbation at around 8 kHz:

reduce noise level or shift it to higher frequencies (MHz frequencies are damped by distribution cables)

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-5 0 5 10 15 20 25 30 35 40 45 50-140

-120

-100

-80

-60

-40

-20

0

Mag

nitu

de s

pect

rum

[dB

]

Frequency [kHz]

EDMS No. 1354977 11/02/2014

New UPS Systems – EMC Performance

Industrial double conversion BORRI UPS selected from invitation to tender

New UPS fully compliant with required standard (IEC-62040-2: EMI and EMC)

CERN internal (re-)qualification of the new UPS with the help of TE-EPC Noise immunity (UPS = victim)

Burst immunity (high frequency, low power): within IEC standards Surge immunity (lightning, high power): very good (2 x IEC standard levels)

Noise emission (UPS = aggressor) EMC conducted noise on AC input/output lines created by the UPS: within IEC standards UPS output (< 100 kHz): the peak at ~8 kHz (now at ~7 kHz) is reduced by a factor 5 UPS output (> 100 kHz): another peak appears at ~1.3 MHz (but still 4 times lower than the existing at 8 kHz)

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EMC Performance Comparison

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0.4Vrms @ 1MHz

3Vrms @ 8kHz

EMC Performance – Situation Assessment in the Tunnel

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UPS output

Downstream distributionswitchboard

Downstream distributionswitchboard with UPS OFF

Local distribution in tunnel

Local distribution in tunnelwith UPS OFF

5 m

150 m

Conclusion

Change of UPS system topology: Conventional double conversion topology much more reliable

New UPS system network configuration Delocalization in points 5, 7 and 8 (R2E project)

UPS network majorly improved during LS1: Safe powering for machine protection system with independent and redundant

paths Availability increased for all users and thus for LHC operation Tolerance to the first UPS failure in each zone

Noise in the 8 kHz range reduced with new UPS systems Noise in the MHz range: ‘false’ problem since noise is attenuated along

the distribution cables Up to now: ~80 new UPS BORRI installed and in operation on surface

and underground, no problem reported today Filtering solution (MHz) being studied with TE-EPC

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EDMS No. 1354977 11/02/2014

lhc ups systems and configurations: changes during the ls1 v. chareyre / en-el lhc beam operation...

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