The Importance of Layout and Configuration Data for Flexibility during Commissionning and Operation of the Lhc Machine Protection Systems

Due to the large stored energies in both magnets and particle beams, the Large Hadron Collider (LHC) requires a large inventory of machine protection systems, as e.g. powering interlock systems, based on a series of distributed industrial controllers for the protection of the more than 10’000 normal and superconducting magnets. Such systems are required to be at the same time fast, reliable and secure but also flexible and configurable to allow for automated commissioning, remote monitoring and optimization during later operation. Based on the generic hardware architecture of the LHC machine protection systems presented at EPAC 2002 [2] and ICALEPS 2003, the use of configuration data for protection systems in view of the required reliability and safety is discussed. To achieve the very high level of reliability, it is required to use a coherent description of the layout of the accelerator components and of the associated machine protection architecture and their logical interconnections. Mechanisms to guarantee coherency of data and repositories and secure configuration of safety critical systems are presented. This paper focuses on the first system being commissioned, the complex magnet powering system, to become fully operational before first injection of beam into the LHC. THE LHC MAGNET POWERING SYSTEM The powering system of the LHC is of unprecedented complexity, including more than 10’000 superconducting and normal conducting magnets distributed around the LHC circumference of 27 km. The interconnection of the superconducting magnets throughout the continuous cryostats is done with more than 80’000 splices and they are connected via a large number of HTS current leads and air and water cooled cables to more than 1700 different power converters, located in the LHC underground areas and in various surface buildings. The concept of powering subsectors In order to limit the stored energies in the electrical circuits and to avoid cables carrying high currents across the insertions, the main magnets are powered separately in each of the eight symmetrical sectors. In each sector there are several cryostats housing the magnets, in total more than 40 around the LHC. In order to further simplify installation, commissioning and operation, the powering system is subdivided into 28 powering subsectors for the superconducting magnets and 8 powering subsectors for normal conducting magnets. For the protection of the described magnet powering system of the LHC, a dedicated Powering Interlock System has been put in place, interfacing with the power converters, the quench protection system (QPS) and energy extraction facilities to assure the protection of magnets and electrical equipment [3]. The system is based on 44 industrial controllers, installed in a number of racks located in various LHC underground areas, whereas the installations and the protection process have to be customized depending on the layout of the machine and the connected user systems and devices [4]. THE LHC FUNCTIONAL LAYOUT DATABASE