Sep 22 – 26, 2014
Centre des Congrès - Aix en Provence, France
Europe/Zurich timezone

Failure Analysis Results and Lessons Learned on LHC Experiments Crate and Power Supply Equipment

Sep 23, 2014, 5:04 PM
Centre des Congrès - Aix en Provence, France

Centre des Congrès - Aix en Provence, France

14 boulevard Carnot 13100
Poster Power First Poster Session


Sylvain Mico (CERN)


The LHC accelerator’s first long shutdown period (LS1), in 2013-2014, has given the experiments the opportunity to perform planned upgrade and maintenance activities on systems and equipment. It has also been the right to conduct a preventive maintenance campaign on crate and power supply equipment which is foreseen to operate smoothly for another 4 to 8 years. This paper will present the lessons learned during the LS1 power supply preventive maintenance activities as well as a in-depth analysis of the most common failure modes and weaknesses observed in LHC power supplies experiment over the past operation years.


Large quantities of high and low DC voltage power supplies (PS) and crates have been procured to house and power sub-detector electronics in the LHC experiments. In order to keep the overall cost and technical integration complexity at a manageable level, the LHC experiments’ sub-detectors have been attempted to standardize as much as possible this kind of equipment. The power supply and crate service in PH-ESE supports this equipment and manages a set of long term maintenance contracts with the different PS and crate manufacturers that, in total, cover over 10’000 objects. Equipment requiring maintenance (verification, calibration, repair or preventive maintenance) is traced individually during the intervention process. The maintenance tasks are centrally managed via a technical database and a maintenance history is recorded for every piece of equipment. Besides tracking equipment, the database offers the possibility to generate detailed statistical analysis of the failure rates, identify possible weak equipment and highlight the type of interventions performed on specific equipment. In addition to this information, the service collaborates closely with the manufacturers who have a deeper knowledge and understanding of the encountered failures, their origin and fixes. LS1 presented a good opportunity to perform an important preventive maintenance campaign for over 800 pieces of equipment. During the preventive maintenance activity, a certain quantity of components has shown weaknesses and failures. This, together with the failure rates and modes observed over the first 5-10 years of operation, gives us the possibility to analyze and possibly understand the main causes of certain PS equipment weaknesses. This paper presents an in-depth PS failure analysis and shares the lessons learned during the LS1 preventive maintenance campaign. Where and when clearly identified and applicable, possible technical and operational recommendations will be formulated in order to mitigate future technical weakness and/or possible failure.

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