Print ISSN 1751-8822
This journal was previously known as IEE Proceedings - Science, Measurement and Technology 1994-2006. ISSN 1350-2344. more..
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Analysis of leakage flux, losses, and temperature in large synchronous generator end zone under the multi‐layer screen thickness based on novel iterative method
- Author(s): Jichao Han ; Jiayu Qiu ; Mingxuan Teng ; Haiming Qi ; Baojun Ge
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p.
1
–11
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AbstractThe multi‐layer screen is the key component in the large synchronous generator end zone. The leakage flux, losses, and temperature of end components are significantly affected by the thickness of multi‐layer screen in the synchronous generator. To investigate the influence of multi‐layer screen thickness on the end leakage flux, losses, and temperature in the synchronous generator end zone, 1407MVA nuclear power synchronous generator is studied. Three‐dimensional transient electromagnetic field model of synchronous generator end zone is established. Three‐dimensional transient electromagnetic field in the end zone of 1407MVA synchronous generator with the multi‐layer screen is calculated based on the novel iterative method. The flux density of end components is compared and studied in the end zone under the variation of multi‐layer screen thickness. Influence of the different thicknesses of multi‐layer screen on the losses of the shield plate, screen, finger plate, and stator end core is researched. The losses of end components obtained from 3D end electromagnetic field calculation are applied to the end zone as the heat source in the three‐dimensional fluid and thermal coupled field. The temperature distribution of the end components is determined. The accuracy of the calculated results is validated by the experimental values.
The multi‐layer screen is the key component in the large synchronous generator end zone. To investigate the influence of multi‐layer screen thickness on the end leakage flux, losses, and temperature in the synchronous generator end zone, 1407 MVA nuclear power synchronous generator is studied. The novel iterative method is proposed and the accuracy of the calculated results is validated by the experimental values.image
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Synchronous switching of uncompensated transmission line, by considering the effect of coupling voltage between the phases, trapped charge and the characteristics of CB
- Author(s): Alireza Karimonnafs
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12
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AbstractThe synchronous closing technology is an effective way to reduce transient current and voltage, prevent equipment failures, and improve power quality. The proposed algorithm, first by considering the coupling voltages between phases and the residual voltages in an uncompensated transmission line, calculates the zero instant of the voltage curves (ZVC instant) across the poles of the circuit breaker (CB) that is ideally the optimum instant to close the CB. Although other studies have utilized ZVC detection by solely considering either coupling or residual voltages. Secondly, the algorithm seeks to account for the mechanical scattering time of the CB and the rate of decrease of dielectric strength (RDDS) by incorporating delay times into the previously calculated delay values. Although other works have investigated the effect of RDDS or mechanical scattering operation time on synchronous switching to some extent, they have not fulfilled any optimization taking both of them into account.By exerting this algorithm, each phase of CB is closed in the ideal optimum closing target (ZVC instant) with a maximum error of one sample, and then, taking into account the CB characteristics, by compensating the RDDS and mechanical scattering time, CB is energized in the optimal time interval, where pre‐strike voltages are minimized.
In this article, a synchronous switching algorithm for closing the circuit breaker in optimum time interval is presented. The mentioned algorithm firstly, calculates the zero voltage crossing state instant and secondly compensates that point by considering rate of decrease of dielectric strength and mechanical scattering time.image
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Differential magnetic field probe calibration based on symmetric de‐embedding technology
- Author(s): Bo Hou ; Shan Xue ; Rui Ding ; Xinxin Tian ; Weiheng Shao
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p.
25
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AbstractThe de‐embedding calibration method has been proposed to achieve high‐precision calibration for a single port electric field or magnetic field probe, which can effectively eliminate the calibration ripple. However, the method's effectiveness for a four‐port calibration system has not been verified yet. In this paper, a four‐port de‐embedding calibration method with a differential magnetic field probe is proposed, and its effectiveness is proved. Two symmetric grounded coplanar waveguide transmission lines are applied in the proposed method to solve the ABCD‐matrix of the embedded part of the calibrator. The de‐embedded S‐parameter model of the four‐port calibration system for differential magnetic field probe can be obtained. The calibration results indicate that the proposed method can also reduce the calibration ripple and compensate for the attenuation caused by the calibrator. Compared with the traditional calibration method using a microstrip line calibrator, the ripples of the proposed method can be reduced by 34%. The analysis results of the frequency interval of the ripple (FIR) in different methods show that the de‐embedding method can reduce the FIRs (except around 1.2 GHz) caused by the reflection of the calibrator and retain the FIR (about 1.2 GHz) caused by the reflection of the probe itself.
Two symmetric grounded coplanar waveguide transmission lines are applied to solving the ABCD‐matrix of the embedded part of the calibrator. By using the ‐matrix of the embedded part, the de‐embedded S‐parameter model of the four‐port calibration system for a differential magnetic field probe can be obtained. Compared with the traditional calibration method using a microstrip line calibrator, the ripples of the proposed method can be reduced by 34%.image
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Design of a multiparameter data acquisition and control system for in situ seabed observation base stations
- Author(s): Chao Zhong ; Jing'an Lu ; Dongju Kang ; Qianyong Liang
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AbstractWith the exploration, development, and research of deep‐sea resources, there is an urgent need for long‐term and continuous observation data of the deep‐sea seabed boundary layer. The traditional method of deep‐sea seabed survey and sampling based on scientific research vessels has the discontinuity of observation data in space and time scales. There are some problems in the seabed in situ observation method based on the seabed observation network for low mobility and high operation and maintenance costs, restricting the in‐depth understanding of the dynamic change process of the deep‐sea floor. To solve the above problems, an open and modular data acquisition control system was designed based on an embedded system and signal processing technology. In terms of the physical, chemical, geological, and ecosystem characteristics of the seafloor or near the seafloor boundary layer, various functional sensors and instrumentation were matched to form an independent underwater integrated measurement or experimental device, eventually realizing in situ multiparameter and long‐time series observations of the seafloor. The system data acquisition and control test were completed through laboratory experiments, which verified the feasibility of the system design. The research showed important theoretical and technical reference significance for the exploration and development of resources in the submarine boundary layer and the promotion of deep‐sea scientific research.
With the exploration, development, and research of deep‐sea resources, there is an urgent need for long‐term and continuous observation data of deep‐sea seabed boundary layer. The traditional method of deep‐sea seabed survey and sampling based on scientific research vessels has the discontinuity of observation data in space and time scales. There are some problems in the seabed in situ observation method based on the seabed observation network for low mobility and high operation and maintenance costs, restricting the in‐depth understanding of the dynamic change process of the deep‐sea floor. To solve the above problems, an open and modular data acquisition control system was designed based on an embedded system and signal processing technology. The system data acquisition and control test were completed through laboratory experiments, which verified the feasibility of the system design. The research showed important theoretical and technical reference significance for the exploration and development of resources in the submarine boundary layer and the promotion of deep‐sea scientific research.image
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Time–frequency representation using IEVDHM–HT with application to classification of epileptic EEG signals
- Author(s): Rishi Raj Sharma and Ram Bilas Pachori
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Intelligent fault diagnosis approach with unsupervised feature learning by stacked denoising autoencoder
- Author(s): Min Xia ; Teng Li ; Lizhi Liu ; Lin Xu ; Clarence W. de Silva
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Speed control of electrical vehicles: a time-varying proportional–integral controller-based type-2 fuzzy logic
- Author(s): Mohammad Hassan Khooban ; Taher Niknam ; Mokhtar Sha-Sadeghi
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Complete protection scheme for fault detection, classification and location estimation in HVDC transmission lines using support vector machines
- Author(s): Jenifer Mariam Johnson and Anamika Yadav
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Statistical investigation of AC breakdown voltage of nanofluids compared with mineral and natural ester oil
- Author(s): Georgios D. Peppas ; Vasilios P. Charalampakos ; Eleytheria C. Pyrgioti ; Michael G. Danikas ; Aristides Bakandritsos ; Ioannis F. Gonos