Analysis of deterioration by partial discharge of XLPE using GCMS and FTIR
Deterioration of polymeric dielectrics by partial discharge (PD) might occur at defects in an insulation layer. To elucidate the mechanism of deterioration by PD, measurements were conducted of the gas components produced during deterioration and the substances created on the surface of cross-linked polyethylene (XLPE) samples subjected to PD. Gas component measurements were performed using an experimental apparatus including GC-MS. Results of gas analyses showed that carbon dioxide (CO2) was produced when the XLPE sample is subjected to the PD in a N2+O2 gas atmosphere. The amount of generated CO2 was confirmed to increase concomitantly with the period of voltage application. The FTIR spectroscopic analysis of substances on the surface of deteriorated XLPE revealed carbonyl compounds on the surface of the deteriorated samples. The deterioration was suppressed when a phenolic antioxidant was added: 44-thiobis-3methyl-6tert butyl phenol. The process of deterioration by PD and the effect of the antioxidant on the deterioration by PD were also discussed.
Physical model of PD behavior and relevant damage growth from micro-cavities in polyethylene-based material under AC voltage
In the framework of developing defect-based life models, in which breakdown is explicitly associated with partial discharge (PD)-induced damage growth from a defect, ageing tests and PD measurements were carried out in the lab on polyethylene (PE) layered specimens containing artificial cavities. PD activity was monitored continuously during aging. A quasi-deterministic series of stages can be observed in the behavior of the main PD parameters (i.e. discharge repetition rate and amplitude). Phase-resolved PD patterns at various ageing stages were reproduced by numerical simulation which is based on a physical discharge model devoid of adaptive parameters. The evolution of the simulation parameters provides insight into the physical-chemical changes taking place at the dielectric/cavity interface during the aging process. PD activity shows similar time behavior under constant cavity gas volume and constant cavity gas pressure conditions, suggesting that the variation of PD parameters may not be attributed to the variation of the gas pressure. Brownish PD byproducts, consisting of oxygen containing moieties, and degradation pits were found at the dielectric/cavity interface. It is speculated that the change of PD activity is related to the composition of the cavity gas, as well as to the properties of dielectric/cavity interface.
The Area of Freedom, Security and Justice ten years on: Successes and future challenges under the Stockholm Programme. CEPS Paperbacks. June 2010
This book celebrates the tenth anniversary of the Area of Freedom, Security and Justice (AFSJ) by bringing together the views of key practitioners and policy-makers who have played an outstanding role in thinking about and shaping EU policies on freedom, security and justice. 
 
Ten years ago, the member states transferred competences to the EU for law and policy-making in the fields of immigration, asylum and border controls, and began the transfer process for criminal justice and policing. This decade of European cooperation on AFSJ policies has experienced very dynamic convergence, the enactment of a large body of European law and the setting-up of numerous EU agencies working in these domains. Such dynamism in policy-making has not been without challenges and vulnerabilities, however. As this collective volume shows, the main dilemmas that lie ahead relate to an effective (while more plural) institutional framework under the Treaty of Lisbon, stronger judicial scrutiny through a greater role for national courts and the Court of Justice in Luxembourg, better mechanisms for evaluating and monitoring the implementation of EU AFSJ law and a more solid fundamental rights strategy. The contributions in this volume address the progress achieved so far in these policy areas, identify the challenges for future European cooperation in the AFSJ and put forward possible paths for making more progress in the next generation of the EU’s AFSJ.