Statistical approach to identify the discharge source in MV cables and accessories

Partial discharge (PD) analysis is a reliable tool to assess the integrity of electrical insulation. Representation and interpretation of the data, obtained from e.g. online PD monitoring, are key issues to reveal the discharge source, i.e. defect type, as well as the physical phenomena behind the occurrence. Analyses of various PD patterns such as discharge height distribution presented in this work provide useful statistical parameters to identify the discharge source. Research shows that the 2-parameter Weibull distribution is a reliable model to quantify the characteristics of the patterns of the defect. The model fits well to the charge-height distribution. In addition, trends in the discharge density pattern that occur over long times, can be used as complementary information to discover the discharge nature. It alerts for a possible failure and therefore assists in taking corrective measures to prevent failure. This paper presents the application of such statistical modeling to the area of on-line power cable diagnostics. Data obtained from laboratory experiments as well as field data have been studied

Technical developments and practical experience in large scale introduction of on-line PD diagnosis

On-line Partial Discharge (PD) detection and location systems for medium-voltage cables are at present being introduced in Dutch utilities and worldwide. The technical challenges now move from the development of the diagnostic technique itself to efficient implementation on alarge scale. In this paper we discuss several implementation related challenges and will propose adequate solutions. These challenges include robust algorithms to determine time of arrivals of distorted PD waveforms, signal propagation along cable types and configurations as three-core and cross bonded cables, and effect of ring main units or substations on signal propagation. Algorithms based on signal energy and on phase angle in frequency domain are preferred above e.g. threshold detection to determine PD arrival times. By introducing effective dielectric properties, cable parameters for accurate fault location as characteristic impedance and propagation velocity can be estimated also if data on semiconducting layers are unavailable. Models are proposed for cross-bonded connections and for three-core cables with common earth screen. A pulse injection circuit, already included in the PD equipment for time synchronisation, can be employed to extract a model for PDs passing ring main units or even entire substations

SupernetNL program: 3.4 km 110 kV AC underground superconducting cable in the Dutch grid

TenneT, a leading European electricity transmission system operator (TSO) is planning to install a 3.4 km long underground superconducting 110 kV cable as part of the Dutch electricity grid, in the city of Enschede. HTS cables have already been demonstrated on a relatively small scale in other countries, but they are usually not part of the meshed high-voltage grid and the length of the relevant cable section generally does not exceed 1 km. In 2009, a 600-meter section of HTS cable was installed in New York, and in 2014 a 1-km long section was taken in operation in Essen, Germany to replace a 10 kV AC medium-voltage line. In the Supernet NL program, TenneT is working together with several leading knowledge institutes including University of Twente, Delft University of Technology, the Institute of Science and Sustain- able Development (IWO), HAN University of Applied Sciences and RH Marine. These institutes have been investigating control engineering aspects and the requirements the cable must meet. In the meantime, the tender process has been started which consists of two phases. In the fi rst phase (summer 2017) appropriate candidates are selected directly followed by a call for tender in August. Receipt of the best and fi nal offer is scheduled for the end of November. In the presentation, the project will be introduced and requirements will be discussed, specifi cally focusing on the cryogenic aspects

Effects of regret in supply chain decisions: An experimental study

In this thesis, effects of regret tendency on supply chain decisions are investigated. To this end, data from a previously conducted laboratory experiment where human subjects play the roles of manufacturer and retailer are used. The subjects make contracting and order quantity decisions under wholesale price, buyback and revenue sharing contract scenarios. Subjects are classified into high-regret and low-regret categories based on their responses to the questionnaire of Schwartz et al. (2002). We analyze the extent of the Pull-to-Center behavior in retailers’ order quantity decisions who face the newsvendor problem. We find high-regret retailers to be more prone to exhibit the preference to minimize ex-post inventory error and demand chasing heuristic under some of the contracts we study. In the wholesale price contract scenario, we observe high-regret manufacturers to offer more attractive contracts to the retailers compared to low-regret manufacturers. We also observe manufacturers to increase the retailer’s predicted profit and profit share in their contract offer following a contract rejection; however, this behavior does not depend on the level of regret tendency

Harmonic resonances due to transmission cables

Godkänd; 2014; 20141209 (matbol

Immunogenicity Evaluation of PLGA Nanoparticles Contains Recombinant CfaB Protein from Enterotoxigenic Escherichia Coli

BACKGROUND AND OBJECTIVE: Enterotoxigenic Escherichia coli (ETEC) are the most common causes of diarrhea among children. Colonization factors (CFs) are the major ETEC candidate vaccines. Considering the high antibiotics resistance reports, construction of effective immunogen against bacteria is major goal. Encapsulation of recombinant immunogen in nano carriers such as polymeric PLGA nanparticles, not only protects them from degradation in environmental elements but also provides the effective concentrations of immunogen in targets, hence  increasing bioactivity. The aim of this study was to investigate the immunogenic properties of CfaB protein encapsulated in PLGA nanoparticles. METHODS: In this research study, cfaB gene codon optimaztion was performed by OPTIMIZER software. Expression of recombinant protein in E.coli was induced with IPTG. The recombinant protein was purified using affinity chromatography and evaluated by Western Blotting analysis. PLGA nanoparticles containing recombinant protein were prepared by double emulsion method and their structures were characterized by SEM and DLS. 40 BALB/C mice in four group were immunized with nanoparticles and antibody titers were determined by ELISA. The efficiency of antibodies in preventing the attachment of ETEC bacteria to the Caco 2 cells was examined. FINDINGS: The optimized gene had a Codon adaptation index (CAI) of 0.85. Expression of recombinant protein led to the production of CfaB with molecular weight of 18/9 kDa. Yield of protein was 5mg/L. Encapsulation efficiency of recombinant protein in PLGA nanoparticles was 85٪. The average particle size was 170 nm. Immunization of mice induced serum antibody response. Immunized sera decreased %62.8 of ETEC adhesion to Caco2 cells. CONCLUSION: Recombinant CfaB protein encapsulated in PLGA nanoparticles stimulate immunity against ETEC

Harmonic resonances due to transmission-system cables

This paper gives some examples of harmonicissues that can occur when long ac cables are connected in thetransmission grid. The main impact is that resonances can occurat much lower frequencies than when only overhead lines arepresent. Two illustrative case studies are presented: one for a275-kV cable, one for a 400-kV cable in combination with a 132-kV capacitor bank. A simple rule-of-thumb is given, to decide ifa detailed harmonic study is needed. Some guidelines for such astudy are given as well.Godkänd; 2014; 20140422 (matbol); Konferensartikel i tidskrift</p

Immunotherapy with IgY Antibodies toward Outer Membrane Protein F Protects Burned Mice against Pseudomonas aeruginosa Infection

Burn patients with multidrug-resistant Pseudomonas aeruginosa infections commonly suffer from high morbidity and mortality, which present a major challenge to healthcare systems throughout the world. Outer membrane protein F (OprF), as a main outer membrane porin, is required for full virulence expression of P. aeruginosa. The aim of this study was to evaluate the protective efficacy of egg yolk-specific antibody (IgY) raised against recombinant OprF (r-OprF) protein in a murine burn model of infection. The hens were immunized with r-OprF, and anti-r-OprF IgY was purified using salt precipitation. Groups of mice were injected with different regimens of anti-OprF IgY or control IgY (C-IgY). Infections were caused by subcutaneous injection of P. aeruginosa strain PAO1 at the burn site. Mice were monitored for mortality for 5 days. The functional activity of anti-OprF IgY was determined by in vitro invasion assays. Immunotherapy with anti-OprF IgY resulted in a significant improvement in the survival of mice infected by P. aeruginosa from 25% to 87.5% compared with the C-IgY and PBS. The anti-OprF IgY decreased the invasion of P. aeruginosa PAO1 into the A549. Passive immunization with anti-OprF IgY led to an efficacious protection against P. aeruginosa burn infection in the burn model

Experiences with on-line PD measurement and interpretation for MV cable systems - field data analysis

On-line partial discharge (PD-OL) monitoring systems for medium voltage cable connections have recently been introduced in Dutch grids and also a few worldwide. The vast continuous stream of diagnostic data calls for a re-evaluation of statistical methods to be applied for the interpretation of the PD activity. In the present paper a variety of statistical parameters are discussed. These parameters include parameters for observing trends in PD activity over time. The methods are applied to data obtained from several continuous online field measurements collected over a year. The results of analyses on several weak spots which were detected before failure are presented. Results of failed accessories are discussed in relation to their prior PD behavior