421 research outputs found

    Data management of on-line partial discharge monitoring using wireless sensor nodes integrated with a multi-agent system

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    On-line partial discharge monitoring has been the subject of significant research in previous years but little work has been carried out with regard to the management of on-site data. To date, on-line partial discharge monitoring within a substation has only been concerned with single plant items, so the data management problem has been minimal. As the age of plant equipment increases, so does the need for condition monitoring to ensure maximum lifespan. This paper presents an approach to the management of partial discharge data through the use of embedded monitoring techniques running on wireless sensor nodes. This method is illustrated by a case study on partial discharge monitoring data from an ageing HVDC reactor

    Radiometric Wireless Sensor Network Monitoring of Partial Discharge Sources in Electrical Substations

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    A wireless sensor network (WSN) with the potential to monitor and locate partial discharge (PD) in high-voltage electricity substations using only received signal strength (RSS) is proposed. The advantages of an RSS-based operating principle over more traditional methods (e.g., time-of-arrival and time-difference-of-arrival) are described. Laboratory measurements of PD that emulate the operation of a PD WSN are presented. The hardware architecture of a prototype PD WSN is described and the particular challenges of an RSS-based location approach in an environment with an unknown, and spatially varying, path-loss index are discussed. It is concluded that an RSS-based PD WSN is a plausible solution for the monitoring of insulation integrity in electricity substations

    Low power radiometric partial discharge sensor using composite transistor-reset integrator

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    The measurement of partial discharge provides a means of monitoring insulation health in high-voltage equipment. Traditional partial discharge measurements require separate installation for each item of plant to physically connect sensors with specific items. Wireless measurement methods provide an attractive and scalable alternative. Existing wireless monitoring technologies which use time-difference-of-arrival of a partial discharge signal at multiple, spatially separated, sensors place high demands on power consumption and cost due to a requirement for rapid sampling. A recently proposed partial discharge monitoring system using a wireless sensor network and measuring received signal strength only, has potential cost and scalability advantages. An incoherent wireless sensor incorporating a transistor-reset integrator has been developed that reduces the measurement bandwidth of the PD events and alleviates the need for high-speed sampling. It is based on composite amplifier techniques to reduce the power requirements by a factor of approximately four without compromising precision. The accuracy of the proposed sensor is compared to that obtained using a high-speed digital sampling oscilloscope. Received energies were measured over a 10 m distance in 1 m increments and produced an error within 1 dB beyond 4 m and 3.2 dB at shorter distances, resulting in a measurement accuracy within 1 m

    Assessment of Effective Radiated Power of the Partial Discharge Emulator Source

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    Two effective partial discharge (PD) measurement techniques are used; a galvanic contact measurement technique similar to the IEC 60270 standard measurement and free-space radiometric (FSR) measurement. Several types of PD sources are specially constructed: two internal PD emulators and an emulator of the floating-electrode type. An AC power supply is applied to the PD source and the radiated signal is captured using a wideband biconical antenna. The calibration of PD sources is demonstrated. Effective radiated power (ERP) of the PD sources using a PD calibration device is determined

    Eradicating hepatitis C:Are novel screening strategies for people who inject drugs cost-effective?

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    Background: In developed countries, people who inject drugs (PWID) have a high prevalence of hepatitis C virus (HCV), yet they are often under-diagnosed. The World Health Organization has set 2030 as a target year for HCV elimination. To meet this target, improving screening in convenient community settings in order to reach infected undiagnosed individuals is a priority. This study assesses the cost-effectiveness of alternative novel strategies for diagnosing HCV infection in PWID. Methods: A cost-effectiveness analysis was undertaken to compare HCV screening at needle exchange centres, substance misuse services and at community pharmacies, with the standard practice of detection during general practitioners’ consultations. A decision tree model was developed to assess the incremental cost per positive diagnosis, and a Markov model explored the net monetary benefit (NMB) and the cost per Quality Adjusted Life Years (QALYs) gained over a lifetime horizon. Results: Needle exchange services provided a 7.45-fold increase in detecting positive individuals and an incremental cost of £12,336 per QALY gained against current practice (NMB £163,827), making this the most cost-effective strategy over a lifetime horizon. Screening at substance misuse services and pharmacies was cost-effective only at a £30,000/QALY threshold. With a 24% discount to HCV treatment list prices, all three screening strategies become cost-effective at £20,000/QALY. Conclusions: Targeting PWID populations with screening at needle exchange services is a highly cost-effective strategy for reaching undiagnosed HCV patients. When applying realistic discounts to list prices of drug treatments, all three strategies were highly cost-effective from a UK NHS perspective. All of these strategies have the potential to make a cost-effective contribution to the eradication of HCV by 2030

    Improved Left Ventricular Mass Quantification with Partial Voxel Interpolation – In-Vivo and Necropsy Validation of a Novel Cardiac MRI Segmentation Algorithm

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    Background—CMR typically quantifies LV mass (LVM) via manual planimetry (MP), but this approach is time consuming and does not account for partial voxel components - myocardium admixed with blood in a single voxel. Automated segmentation (AS) can account for partial voxels, but this has not been used for LVM quantification. This study used automated CMR segmentation to test the influence of partial voxels on quantification of LVM. Methods and Results—LVM was quantified by AS and MP in 126 consecutive patients and 10 laboratory animals undergoing CMR. AS yielded both partial voxel (ASPV) and full voxel (ASFV) measurements. Methods were independently compared to LVM quantified on echocardiography (echo) and an ex-vivo standard of LVM at necropsy. AS quantified LVM in all patients, yielding a 12-fold decrease in processing time vs. MP (0:21±0:04 vs. 4:18±1:02 min; pFV mass (136±35gm) was slightly lower than MP (139±35; Δ=3±9gm, pPV yielded higher LVM (159±38gm) than MP (Δ=20±10gm) and ASFV (Δ=23±6gm, both pPV and ASFV correlated with larger voxel size (partial r=0.37, pPV yielded better agreement with echo (Δ=20±25gm) than did ASFV (Δ=43±24gm) or MP (Δ=40±22gm, both pPV and ex-vivo results were similar (Δ=1±3gm, p=0.3), whereas ASFV (6±3g, P\u3c0.001) and MP (4±5 g, P=0.02) yielded small but significant differences with LVM at necropsy

    The Grizzly, January 28, 1991

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    Policies and Statistics, A Security Concern: New Quad Regulations; Crime Report Released • Sonia Sanchez: Poet for Peace • Gulf Dialogue Continues • Independence Dogs • Financial Aid Month • You Asked for it: You Got It!! • New Quad Policy • Presidency Symposium • When is Dr. Martin Luther King, Jr.\u27s Birthday? • Who\u27s Who Announced • Mission Conference Held • Back to the Basics • The Innocent • Swimmers on Win Streak • Women Hope for Good Things to Come • A Roller Coaster Season for the Hoopsters • Women Rounding-out Season • The Dream Lives On • Letter: Bundle Up! • Researchers Psyched Out • The Technology of War • A Wasted Solution?https://digitalcommons.ursinus.edu/grizzlynews/1268/thumbnail.jp
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