Power Converters and Power Quality

This paper discusses the subject of power quality for power converters. The first part gives an overview of most of the common disturbances and power quality issues in electrical networks for particle accelerators, and explains their consequences for accelerator operation. The propagation of asymmetrical network disturbances into a network is analysed. Quantitative parameters for network disturbances in a typical network are presented, and immunity levels for users' electrical equipment are proposed. The second part of this paper discusses the technologies and strategies used in particle accelerator networks for power quality improvement. Particular focus is given to networks supplying loads with cycling active and reactive power.Comment: 26 pages, contribution to the 2014 CAS - CERN Accelerator School: Power Converters, Baden, Switzerland, 7-14 May 201

Static Var Compensator Project for the SPS Electrical Network

This paper gives a progress report on the Static Var Compensator project BEF2 for the SPS electrical network. Following a market survey and a call for tenders, a contract has been awarded to ABB Sweden and the project is now in the phase of detailed performance studies, system design and ordering of the main electrical components. This progress report describes the electrical design, summarises the results of the harmonic filter design studies, discusses the interfacing of the control- and communication system and explains the mechanical layout of the Static Var Compensator and as well as the project co-ordination with the feeding BE substation renovation project. Finally, the project planning is presented and critical paths are evaluated

The status (2009) of CERN’s Static Var Compensators and the future role of BEQ1/BB3

As of 1 January 2009, CERNs Static Var Compensators have been transferred from EN-EL to TE-EPC. During 2009, the SVC's will be operated jointly by these two groups. This technical note describes the technical state of the Static Var Compensators (2009), gives an overview of required renovation work and analyses the situation of spare parts. In particular, the document discusses to which degree budgets shall be allocated to maintain and continue to operate the spare SVCs BEQ1 (1974) and BB3 (1982) for SPS. Should we invest in a complete renovation of BEQ1 and BB3, or should we purchase additional spare parts for the modern BEQ2 and BEQ3? The strategy proposed in this technical note has been approved by the IEFC on 4.9.2009

Static Var Compensation for the SPS Electrical Network

The electrical installations of the SPS pulsed electrical network consist of power converters for dipoles and quadrupoles, RF cavities and the north experimental area. Large pulsing loads like these can only be connected to the 18 kV electrical network if a Static Var Compensator takes care of reactive power compensation, voltage control and harmonic filtering. This paper explains the underlying principles of static var compensation and gives an overview of the existing two saturated reactor compensators. Finally, a project description is given for the planned installation of a third Static Var Compensator for the SPS pulsed network which will be based on Thyristor Controlled Reactor technology

Leveraging unique structural characteristics of WNK kinases to achieve therapeutic inhibition

This is the author accepted manuscript. The final version is available from American Association for the Advancement of Science via the DOI in this record.The with-no-lysine (K) WNK kinases are master regulators of the Na+-(K+)-Cl- cotransporters, including the renal-specific NCC and NKCC2 cotransporters. The discovery of WNK463, an orally bioavailable pan-WNK kinase inhibitor that exploits unique structural properties of the WNK catalytic domain to achieve high affinity and kinase selectivity, illustrates a strategy of leveraging distinct kinase features to develop specific inhibitors and validates the genetic predictions of the in vivo pharmacology of WNK inhibition

Project factsheet for EC DG RTD brochure

The European Commission DG Research brochure contains project factsheets for FP7 funded Integrated Activities projects. Each factsheet is one page (recto-verso) detailing the general aims and scope of the project. The factsheets are directed at the general public

Is Performance Variability Necessary? A Qualitative Study on Cognitive Resilience in Forestry Work

In forestry work, conditions exist and develop that are complex, unpredictable, and highly consequential and therefore cannot be handled entirely by following static work procedures. Cognitive adjustments are necessary. The objective of this research was to determine whether performance (cognitive) variability is actually necessary to safely fell trees in the coastal region of British Columbia, Canada. In this paper two perspectives were contrasted: the traditional view of safety and the resilience perspective. A collection of empirical evidence established that while safe work procedures provide a good foundation, it is individual performance variability shaped by experience and ‘‘know-how’’ that guides the application of technical skills in such a complex, dynamic, high-risk environment

EuCARD Newsletter Issue 1

European Coordination for Accelerator Research and Development (EuCARD) Newsletter Issue 1: April - June 2009 * A word from the Coordinator * EuCARD in a nutshell * The EuCARD website * MICE - see how they run * For EuCARD members: FAQ

The new 150 MVAr, 18 kV static var compensator for SPS: background, design and commissioning

A new Static Var Compensator (SVC) was designed, installed and commissioned by ABB for CERN’s Super Proton Synchrotron (SPS) accelerator. Due to the sensitive nature of the pulsating power converter load for the SPS magnets, very strict requirements were imposed on the stabilisation of the 18 kV bus voltage and its harmonic distortion. The adopted solution comprises a 150 Mvar TCR and eight harmonic filters with a total power of 130 Mvar. The paper gives a detailed description of the project background, system design and SVC installation. Finally, the results of the SVC performance tests are presented

FAS-dependent cell death in α-synuclein transgenic oligodendrocyte models of multiple system atrophy

Multiple system atrophy is a parkinsonian neurodegenerative disorder. It is cytopathologically characterized by accumulation of the protein p25α in cell bodies of oligodendrocytes followed by accumulation of aggregated α-synuclein in so-called glial cytoplasmic inclusions. p25α is a stimulator of α-synuclein aggregation, and coexpression of α-synuclein and p25α in the oligodendroglial OLN-t40-AS cell line causes α-synuclein aggregate-dependent toxicity. In this study, we investigated whether the FAS system is involved in α-synuclein aggregate dependent degeneration in oligodendrocytes and may play a role in multiple system atrophy. Using rat oligodendroglial OLN-t40-AS cells we demonstrate that the cytotoxicity caused by coexpressing α-synuclein and p25α relies on stimulation of the death domain receptor FAS and caspase-8 activation. Using primary oligodendrocytes derived from PLP-α-synuclein transgenic mice we demonstrate that they exist in a sensitized state expressing pro-apoptotic FAS receptor, which makes them sensitive to FAS ligand-mediated apoptosis. Immunoblot analysis shows an increase in FAS in brain extracts from multiple system atrophy cases. Immunohistochemical analysis demonstrated enhanced FAS expression in multiple system atrophy brains notably in oligodendrocytes harboring the earliest stages of glial cytoplasmic inclusion formation. Oligodendroglial FAS expression is an early hallmark of oligodendroglial pathology in multiple system atrophy that mechanistically may be coupled to α-synuclein dependent degeneration and thus represent a potential target for protective intervention