DIAGNOSTIC TECHNIQUES OF MV CABLE JOINTS UNDER DIFFERENT ENVIRONMENTAL CONDITIONS

The article reports the results and the advances of the experimentation in progress at the RSE laboratories for a diagnostic analysis of the causes of failures that affect MV cable joints, especially during the summer periods. To this purpose two different ad hoc experimental set-ups, consisting of cables equipped with different types of joints to form a ring in short-circuit, have been realized. The rings, energized at rated voltage, are loaded with current to reproduce the daily load variation typical of a MV cable network. The first set-up simulated the reduced thermal conductivity of the soil during summer periods and the second, now under test, allows to simulate, in a controlled way, the presence of rain, even of considerable intensity

IEC 61850-based smart automation system logic to improve reliability indices in distribution networks

This paper proposes an automation system logic for distribution networks with the aims of improving reliability indices through the implementation of selective fault detection, fast network reconfiguration ad automatic back-feeding. A hierarchical approach of smart substations is presented base on IEC 61850 standard, electronic instruments, optical fiber communication network, etc. The protection and control system includes three main blocks: primary substation protection, secondary substation protection and the logic selectivity. These three blocks contribute to create the smart automation system which can improve protection performance, in order to transform most of the faults to transitory interruptions lasting less than one second, and control capability of the system. The main issues and challenges of the automation system logic are presented with a detailed description of primary and secondary substations protection system and relays as well as the logic selectivity. Moreover, a case study on a real DN is reported to demonstrate the effectiveness of the proposed approach

Extreme Weather Conditions Effects On Underground Cable Joints Failures: Strategies For Reliability And Resilience Improvement

In recent years, an abnormal increase of faults in underground Medium Voltage (MV) cable joints has been recorded, especially during summer, by distribution system operators in Italy and worldwide. To preserve an adequate level of reliability and resilience, the causes of such failures have to be investigated to find the most appropriate countermeasures in terms of technological improvement and new planning and operation approaches. Based on the field experience gained by Unareti on Milano and Brescia distribution networks, this paper reports the main results of the analysis of extreme weather conditions' effects on MV underground cable joint failures. Moreover, actions making in place by Unareti, the distribution system operator of Milano and Brescia, for reliability and resilience improvement are listed. The gained information could help redesign innovative, more robust, and resilient joints for MV underground cables and guide distribution system operators in rethinking their distribution network planning and operation paradigms

IEC 61850-based smart automation system logic to improve reliability indices in distribution networks

This paper proposes an automation system logic for distribution networks with the aims of improving reliability indices through the implementation of selective fault detection, fast network reconfiguration ad automatic back-feeding. A hierarchical approach of smart substations is presented base on IEC 61850 standard, electronic instruments, optical fiber communication network, etc. The protection and control system includes three main blocks: primary substation protection, secondary substation protection and the logic selectivity. These three blocks contribute to create the smart automation system which can improve protection performance, in order to transform most of the faults to transitory interruptions lasting less than one second, and control capability of the system. The main issues and challenges of the automation system logic are presented with a detailed description of primary and secondary substations protection system and relays as well as the logic selectivity. Moreover, a case study on a real DN is reported to demonstrate the effectiveness of the proposed approach

Optimal plasma progranulin cutoff value for predicting null progranulin mutations in neurodegenerative diseases : a multicenter Italian study

Background: Recently, attention was drawn to a role for progranulin in the central nervous system with the identification of mutations in the progranulin gene (GRN) as an important cause of frontotemporal lobar degeneration. GRN mutations are associated with a strong reduction of circulating progranulin and widely variable clinical phenotypes: thus, the dosage of plasma progranulin is a useful tool for a quick and inexpensive large-scale screening of carriers of GRN mutations. Objective: To establish the best cutoff threshold for normal versus abnormal levels of plasma progranulin. Methods:309 cognitively healthy controls (25-87 years of age), 72 affected and unaffected GRN+ null mutation carriers (24-86 years of age), 3 affected GRN missense mutation carriers, 342 patients with neurodegenerative diseases and 293 subjects with mild cognitive impairment were enrolled at the Memory Clinic, IRCCS S. Giovanni di Dio-Fatebenefratelli, Brescia, Italy, and at the Alzheimer Unit, Ospedale Maggiore Policlinico and IRCCS Istituto Neurologico C. Besta, Milan, Italy. Plasma progranulin levels were measured using an ELISA kit (AdipoGen Inc., Seoul, Korea). Results: Plasma progranulin did not correlate with age, gender or body mass index. We established a new plasma progranulin protein cutoff level of 61.55 ng/ml that identifies, with a specificity of 99.6% and a sensitivity of 95.8%, null mutation carriers among subjects attending to a memory clinic. Affected and unaffected GRN null mutation carriers did not differ in terms of circulating progranulin protein (p = 0.686). A significant disease anticipation was observed in GRN+ subjects with the lowest progranulin levels. Conclusion: We propose a new plasma progranulin protein cutoff level useful for clinical practice. Copyright (C) 2011 S. Karger AG, Base