Journal articles: 'Line impedance stabilization network'

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Zhu, Zhibo, Yang Zhao, Wei Yan, Xingfa Liu, and Ming Ju. "Modeling of line impedance stabilization network impedance characteristic based on genetic algorithm." Microelectronics Journal 113 (July 2021): 105095. http://dx.doi.org/10.1016/j.mejo.2021.105095.

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Ibuchi, Takaaki, Shunji Mori, and Tsuyoshi Funaki. "Experimental evaluation of mutual coupling influence on the isolation characteristics of a dual-port v-type line impedance stabilization network." IEEE Electromagnetic Compatibility Magazine 7, no. 1 (2018): 39–45. http://dx.doi.org/10.1109/memc.0.8339540.

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Slimani, Helima, Abdelhakim Zeghoudi, Abdelber Bendaoud, Abdeldjalil Reguig, Baghdadi Benazza, and Nassireddine Benhadda. "Experimental Measurement of Conducted Emissions Generated by Static Converters in Common and Differential Modes." European Journal of Electrical Engineering 23, no. 3 (June 21, 2021): 273–79. http://dx.doi.org/10.18280/ejee.230312.

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The commutation of semiconductors and their interactions with parasitic elements linked to the environment is known to be the main source of interferences conducted in power electronic converters. Thus, identifying these sources of interferences in commutation cells and determining the level of these conducted emissions generated in energy conversion systems presents a major challenge for designers. In this work, a study of the electromagnetic interferences (EMI) generated by the association of serial rectifier-chopper connected to a Line Impedance Stabilization Network (LISN) is proposed, in which a determination of these interferences is presented in both common and differential modes. All simulations are carried out using the LT-spice software and the results obtained are validated by experimental measurements realized at APELEC laboratory (University of Sidi Bel-Abbes, Algeria).

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Stepins, Deniss. "Conducted EMI of Switching Frequency Modulated Boost Converter." Electrical, Control and Communication Engineering 3, no. 1 (August 1, 2013): 12–18. http://dx.doi.org/10.2478/ecce-2013-0009.

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Abstract In this paper conducted electromagnetic interference (EMI) of boost converter with switching frequency modulation (SFM) is theoretically analyzed in details. In the analysis line impedance stabilization network parameters, power inductor and input filtering capacitor parameters are taken into account. The analysis shows that the conducted EMI attenuation due to the use of SFM depends not only on modulation index as it is assumed in numerous research papers, but also on central switching frequency. Useful expressions to numerically calculate SFM boost converter conducted EMI spectrum and attenuation due to the use of triangular and sawtooth modulation waveforms are derived. Additionally experimental verification of the theoretical results is performed using a superheterodyne spectrum analyzer. Moreover a procedure for the choice of optimum SFM parameters (modulation waveform, frequency deviation and modulation frequency) to get maximum conducted EMI attenuation is proposed.

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Wan, Lu, Abduselam Hamid Beshir, Xinglong Wu, Xiaokang Liu, Flavia Grassi, Giordano Spadacini, Sergio Amedeo Pignari, Michele Zanoni, Liliana Tenti, and Riccardo Chiumeo. "Black-Box Modelling of Low-Switching-Frequency Power Inverters for EMC Analyses in Renewable Power Systems." Energies 14, no. 12 (June 9, 2021): 3413. http://dx.doi.org/10.3390/en14123413.

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Electromagnetic interference (EMI) from renewable power systems to the grid attracts more attention especially in the low-frequency range, due to the low switching frequency of high-power inverters. It is significantly important to derive EMI models of power inverters as well as to develop strategies to suppress the related conducted emissions. In this work, black-box modelling is applied to a three-phase inverter system, by implementing an alternative procedure to identify the parameters describing the active part of the model. Besides, two limitations of black-box modelling are investigated. The first regards the need for the system to satisfy the linear and time-invariant (LTI) assumption. The influence of this assumption on prediction accuracy is analysed with reference to the zero, positive and negative sequence decomposition. It is showing that predictions for the positive/negative sequence are highly influenced by this assumption, unlike those for the zero sequence. The second limitation is related to the possible variation of the mains impedance which is not satisfactorily stabilized at a low frequency outside the operating frequency range of standard line impedance stabilization networks.

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Wang, Yi, Han Tang, Wen Li Chen, Xing Zhe Hou, Hong Liang Sun, and Kai Bo Luo. "Research on the Measurement of Household Appliance Impedance Characteristic." Advanced Materials Research 986-987 (July 2014): 1574–78. http://dx.doi.org/10.4028/www.scientific.net/amr.986-987.1574.

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Impedance of power line channel is the most important factor for power line communication. All kinds of household appliances randomly connect or disconnect from the network, which give rise to impedance variation on power line channel. The mismatch of impedance would reduce the performance of the signal transmission. The power network is mixed with lines and loads. In order to investigate the main factors that affect power network impedance, this paper proposed a method to measure the impedance of active household appliances. Some household appliances are measured with this method, and the result shows that this method can measure the impedance effictively, which helps the study on the impedance charicteristics.

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Jung, Sungchan, and Youngoo Yang. "Miniaturized branch-line hybrid coupler with broadband impedance matching network." Journal of Electromagnetic Waves and Applications 27, no. 10 (May 31, 2013): 1230–37. http://dx.doi.org/10.1080/09205071.2013.805168.

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Reynoso-Hernandez, J. Apolinar, M. A. Pulido-Gaytan, R. Cuesta, J. R. Loo-Yau, and M. C. Maya-Sanchez. "Transmission Line Impedance Characterization Using an Uncalibrated Vector Network Analyzer." IEEE Microwave and Wireless Components Letters 30, no. 5 (May 2020): 528–30. http://dx.doi.org/10.1109/lmwc.2020.2984377.

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Hallak, George, Christoph Niess, and Gerd Bumiller. "Accurate Low Access Impedance Measurements With Separated Load Impedance Measurements on the Power-Line Network." IEEE Transactions on Instrumentation and Measurement 67, no. 10 (October 2018): 2282–93. http://dx.doi.org/10.1109/tim.2018.2814138.

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Anyaka, Boniface Onyemaechi, and Innocent Onyebuchi Ozioko. "Transmission line short circuit analysis by impedance matrix method." International Journal of Electrical and Computer Engineering (IJECE) 10, no. 2 (April 1, 2020): 1712. http://dx.doi.org/10.11591/ijece.v10i2.pp1712-1721.

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Fault analysis is the process of determining the magnitude of fault voltage and current during the occurrence of different types of fault in electrical power system. Transmission line fault analysis is usually done for both symmetrical and unsymmetrical faults. Symmetrical faults are called three-phase balance fault while unsymmetrical faults include: single line-to-ground, line-to-line, and double line-to-ground faults. In this research, bus impedance matrix method for fault analysis is presented. Bus impedance matrix approach has several advantages over Thevenin’s equivalent method and other conventional approaches. This is because the off-diagonal elements represent the transfer impedance of the power system network and helps in calculating the branch fault currents during a fault. Analytical and simulation approaches on a single line-to-ground fault on 3-bus power system network under bolted fault condition were used for the study. Both methods were compared and result showed negligible deviation of 0.02% on the average. The fault currents under bolted condition for the single line-to-ground fault were found to be 4. 7244p.u while the bus voltage is 0. 4095p.u for buses 1 and 2 respectively and 0. 00p.u for bus 3 since the fault occurred at this bus. Therefore, there is no need of burdensomely connecting the entire three sequence network during fault analysis in electrical power system.

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Huawei, Zhan, Liu Weina, Li Qiaoyu, Yan Tingting, and Zheng Jie. "Property Analysis and Experimental Study of the Broadband Transmission-Line Transformer in Multimode Feed Network." Open Electrical & Electronic Engineering Journal 9, no. 1 (May 29, 2015): 153–59. http://dx.doi.org/10.2174/1874129001509010153.

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Transmission-line transformers are circuits useful for microwave impedance matching applications due to their broad operating bandwidth. Multimode feed network is composed of two substructures, which are constituted by the transmission-line transformer. Beginning with the broadband transmission-line transformer with 4:1 impedance transformation, supposing the currents on the two lines are not equal but opposite and with the application of two line transmission- line theory, the current-voltage relationships of the asymmetrical (current) bifilar even transmission-line are obtained. An equivalent model with mutual coupling between the subject transmission-lines has been proposed, and its characteristics for impedance transformation have been analyzed. Also, a useful and effective analytic method for bifilar transmission- line transformer has been proposed. The calculated values are in good agreement with the metrical values. So in real application it can better improve the performance of the component and can be used more efficiently.

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Wang and Cao. "A Review of Impedance Matching Techniques in Power Line Communications." Electronics 8, no. 9 (September 12, 2019): 1022. http://dx.doi.org/10.3390/electronics8091022.

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Impedance mismatch that degrades signal power transfer and affects communication reliability is a major obstacle for power line communications (PLC). Impedance matching techniques can be designed to effectively compensate for the impedance mismatch between PLC modems and power line networks at a specific frequency or for a given frequency band. In this paper, we discuss the tradeoffs that need to be made when designing an effective impedance matching network. We also make a comprehensive review of previous state-of-the-art PLC impedance matching techniques and provide a useful classification of each technique. Finally, we discuss important issues (concerns) and provide suggestions for research directions deserving more attention. This review provides a useful guideline for researchers and manufacturers to quickly understand impedance matching principles and facilitate the design of an effective impedance matching coupler for PLC applications.

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Babayomi, Oluleke O., and Peter O. Oluseyi. "Intelligent Fault Diagnosis in a Power Distribution Network." Advances in Electrical Engineering 2016 (October 19, 2016): 1–10. http://dx.doi.org/10.1155/2016/8651630.

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This paper presents a novel method of fault diagnosis by the use of fuzzy logic and neural network-based techniques for electric power fault detection, classification, and location in a power distribution network. A real network was used as a case study. The ten different types of line faults including single line-to-ground, line-to-line, double line-to-ground, and three-phase faults were investigated. The designed system has 89% accuracy for fault type identification. It also has 93% accuracy for fault location. The results indicate that the proposed technique is effective in detecting, classifying, and locating low impedance faults.

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Passerini, Federico, and Andrea M. Tonello. "Analysis of High-Frequency Impedance Measurement Techniques for Power Line Network Sensing." IEEE Sensors Journal 17, no. 23 (December 1, 2017): 7630–40. http://dx.doi.org/10.1109/jsen.2017.2732737.

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Lin, Shih-Tin, and Jien-Shuin Lee. "Impedance control with on-line neural-network compensator for robot contact tasks." Journal of Intelligent and Robotic Systems 15, no. 4 (April 1996): 389–99. http://dx.doi.org/10.1007/bf00437603.

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H. Rawa, Muhyaddin J. "Characteristic and Surge Impedance Variation Impact on Transmission Line Performance." International Journal of Electrical and Computer Engineering (IJECE) 8, no. 4 (August 1, 2018): 2602. http://dx.doi.org/10.11591/ijece.v8i4.pp2602-2607.

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<span>Modeling of power systems is essential to perform various network analyses. Voltage regulation, line losses and transmission line efficiency are greatly affected by transmission line parameters. Hence, accurate modeling of transmission line is required. The aim of this paper is to study the impact of characteristic and surge impedances on voltage profile, voltage regulation and transmission line efficiency.</span>

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Sharma, Rohit, T. Chakravarty, Sunil Bhooshan, and A. B. Bhattacharyya. "Characteristic Impedance of a Microstrip-Like Interconnect Line in Presence of Ground Plane Aperture." International Journal of Microwave Science and Technology 2007 (February 7, 2007): 1–5. http://dx.doi.org/10.1155/2007/41951.

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We propose new empirical expressions for the characteristic impedance of a microstrip-like interconnect line in presence of ground plane aperture. The existing characteristic impedance expressions are modified so as to include the effect of the ground plane aperture. The variation in the characteristic impedance vis-à-vis the aperture size is established. The proposed expressions are general and valid for a range of dielectric materials concerning MICs, RFICs, and PCBs. The results are validated by measurements performed on a vector network analyzer.

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Liu, Heng, Zhao Yang Zeng, and Yi Min Guo. "Three-Dimension Impedance Representation for Microwave Absorptive Ceramics." Key Engineering Materials 544 (March 2013): 489–92. http://dx.doi.org/10.4028/www.scientific.net/kem.544.489.

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The application of three-dimension impedance representation for microwave absorptive ceramics was investigated. Based on transmission line theory, the electro-magnetic property of the ceramics was equivalent to impedance of a three-dimensional impedance network, and the surface effect was described by an added layer with certain impedance. Finally the usability of this representation was discussed by comparing the calculated data with the measurement results.

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Lee, T. H., S. S. Ge, and C. P. Wong. "Adaptive neural network feedback control of a passive line-of-sight stabilization system." Mechatronics 8, no. 8 (December 1998): 887–903. http://dx.doi.org/10.1016/s0957-4158(98)00030-0.

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Guan, Chai-Eu, and Takafumi Fujimoto. "Design of a Wideband L-Shape Fed Microstrip Patch Antenna Backed by Conductor Plane for Medical Body Area Network." Electronics 9, no. 1 (December 24, 2019): 21. http://dx.doi.org/10.3390/electronics9010021.

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This paper describes a compact patch antenna intended for medical body area network. The antenna is fed using a proximity coupling scheme to support the antenna that radiates in the free space and on the human body at the 2.45 GHz ISM band. The conductor plane is placed 2 mm or 0.0163λ0 (λ0 is free space wavelength at 2.45 GHz) below the antenna to reduce backward radiation to the human body. Separation distance must be kept above 2 mm, otherwise, gain of the proposed antenna decreases when antenna is situated on the human body. The L-shape feed line is introduced to overcome impedance mismatch caused by the compact structure. The coupling gap between the proposed antenna and the length of the L-shape feed line are optimized to generate dual resonances mode for wide impedance bandwidth. Simulation results show that specific absorption rate (SAR) of the proposed antenna with L-shape feed line is lower than conventional patch antenna with direct microstrip feed line. The proposed antenna achieves impedance bandwidth of 120 MHz (4.89%) at the center frequency of 2.45 GHz. The maximum gain in the broadside direction is 6.2 dBi in simulation and 5.09 dBi in measurement for antenna in the free space. Wide impedance bandwidth and radiation patterns insensitive to the presence of human body are achieved, which meets the requirement of IoT-based wearable sensor.

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Coskuner, Ertugrul, and Joan J. Garcia-Garcia. "Metamaterial Impedance Matching Network for Ambient RF-Energy Harvesting Operating at 2.4 GHz and 5 GHz." Electronics 10, no. 10 (May 17, 2021): 1196. http://dx.doi.org/10.3390/electronics10101196.

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This paper points out the viability of the utilization of metamaterial transmission lines as a multifrequency impedance matching network, improving RF-Energy Harvesting systems operating around 2.4 GHz and 5 GHz. Metamaterial transmission lines introduce additional degrees of freedom in the transmission line design, providing the possibility to match the impedance in multiple bands. The impedance matching structure has been designed and optimized using ADS simulator to match the input impedance of a four-diode-bridge rectifier connected to an energy management system. The proposed Metamaterial Impedance Matching Network (MIMN) has been fabricated using standard PCB technologies and tested in a full operative ambient RF-Energy Harvesting System obtaining a DC output voltage of 1.8 V in a 6.8 mF supercapacitor.

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Xu, Qiang Ye, Jin Lian, and Hao Lian. "An Adaptive Protection Method for Power System under Wide Area Networks." Advanced Materials Research 403-408 (November 2011): 4189–93. http://dx.doi.org/10.4028/www.scientific.net/amr.403-408.4189.

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The grid structure and its operation mood are becoming more complicated with the expansion of China Power Network which have higher requirement for security protection for relay protection network. This article proposes adaptive setting of switch positioner and line fault under wide area networks. Adaptive setting of switch positioner in system operation mode can effectively extend the protection scope of zone 2 impedance relay on the premise of protecting the cooperative relationship which has a better sensibility than traditional setting value of zone 2 impedance relay. Adaptive setting of line fault has high level of adaptation in system operation mode and sensitivity in each adjacent line which has lager protection scope than that of the traditional setting value and switch positioner.

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Liangzhi, Sun, Jia Kaili, Jia Pi, Jiang Lixiao, and Chen Zijian. "Sequence component direction element based on power frequency variation." E3S Web of Conferences 252 (2021): 02083. http://dx.doi.org/10.1051/e3sconf/202125202083.

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Unlike the relatively stable network structure of the transmission and distribution network, under the new distribution network, resulting in errors in the impedance tuning of the fault directional element, misjudgment of the fault directional element, and a decrease in sensitivity. For this reason, this paper proposes a sequence component adaptive fault directional element based on power frequency variation. The sequence impedance amplitude is calculated through the measured values of the voltage sequence component and the current sequence component of the relay location. Then the phase angle of the setting impedance is determined according to various sequence components in the system. It improves the problem that the setting impedance of power frequency distance directional element is greatly affected by the amplitude and phase angle fluctuation of distribution system impedance and line impedance. The reliability and stability of the sequence component adaptive fault directional element based on the power fresquency variation are verified by Matlab simulation.

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Li, Li. "A Fault Line Detection Method Based on Wavelet Packet Analysis in Distribution Network." Advanced Materials Research 614-615 (December 2012): 1833–40. http://dx.doi.org/10.4028/www.scientific.net/amr.614-615.1833.

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With the rapid development of power network automation, the detection of the default single-phase grounding fault line in small current neutral grounding system has became a hot spot in research of power network system. Generally, power network neutral point is not grounded or grounded through arc-suppression coil grounding. When single phase grounding fault occurs, the power network system is named as small current grounding system since the grounding short-circuit is small due to a low-impedance short circuit.

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Grebennikov, Andrei. "A simple stepped-impedance transmission line load network for inverse Class F power amplifiers." Microwave and Optical Technology Letters 53, no. 5 (March 21, 2011): 1157–60. http://dx.doi.org/10.1002/mop.25923.

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Li, Jia, Xi, and Chen. "Mechanism Analysis of Sympathetic Inrush in Traction Network Cascaded Transformers Based on Flux-Current Circuit Model." Energies 12, no. 21 (November 4, 2019): 4210. http://dx.doi.org/10.3390/en12214210.

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When electric multiple units (EMU) pass the neutral zone, the traction transformer may generate sympathetic inrush, which will cause a malfunction in the transformer differential protection. In order to study the mechanism of the sympathetic inrush of the cascaded traction transformer, the flux–current model of the transformer, line impedance, power system voltage source, and other loads was established. On the basis of the flux–current circuit model, the influence of different factors on the sympathetic inrush of the traction transformer was analyzed. The analysis results were verified by simulation. Research results show that the remanence, closing angle, line impedance, and load will affect the duration and amplitude of the sympathetic inrush.

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Jeong, Bong-Sang, and Yeong-Han Chun. "Feeder Loop Line Control for the Voltage Stabilization of Distribution Network with Distributed Generators." Journal of Electrical Engineering and Technology 9, no. 1 (January 1, 2014): 1–5. http://dx.doi.org/10.5370/jeet.2014.9.1.001.

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Chiu, Leung. "Wideband Microstrip 90° Hybrid Coupler Using High Pass Network." International Journal of Microwave Science and Technology 2014 (April 7, 2014): 1–6. http://dx.doi.org/10.1155/2014/854346.

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A wideband 90° hybrid coupler has been presented and implemented in planar microstrip circuit. With similar structure of conversional 2-section branch-line coupler, the proposed coupler consists of a lumped high-pass network but not the quarter wavelength transmission at the center. The values of all lumped elements were optimized to replace a quarter-wavelength transmission line with a phase inverter. To demonstrate the proposed concept, a 1-GHz prototype was fabricated and tested. It achieves 90% impedance bandwidth with magnitude of S11 less than −10 dB. Within this bandwidth, more than 13 dB port-to-port isolation, less than 5.0 degree phase imbalance, and less than 4.5 dB magnitude imbalance are achieved, simultaneously. The proposed coupler not only achieves much wider bandwidth but also occupies less circuit area than that of the conversional 2-section branch-line coupler.

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Xi, Xinyu, Dehong Li, Dongwen Chen, and Yong Li. "Application of frequency optimization neural network method on power line communication." E3S Web of Conferences 300 (2021): 01018. http://dx.doi.org/10.1051/e3sconf/202130001018.

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The quality of broadband power line carrier communication mainly depends on the carrier communication frequency. However, there is a lack of fast and effective optimal carrier frequency selection method. One frequency selection method based on frequency point optimization neural network is proposed by this paper. This method combines transmission line theory and voltage partial reflection theory to build a power line carrier channel mathematical model of the distribution network. The input frequency point sample set is used as the training set of the frequency point optimization neural network to obtain a neural network model that can predict the local optimal frequency point set. Then the actual distribution network is taken as an example for simulation analysis. When inputting any frequency range, the model outputs the corresponding optimal frequency point set. Simulation results show that the algorithm saves a lot of input impedance or channel strength testing time, while the error rate is limited to about 3%.

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Xiu, Wanjing, and Yuan Liao. "Fault Location Methods for Ungrounded Distribution Systems Using Local Measurements." International Journal of Emerging Electric Power Systems 14, no. 5 (August 27, 2013): 467–76. http://dx.doi.org/10.1515/ijeeps-2013-0079.

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Abstract This article presents novel fault location algorithms for ungrounded distribution systems. The proposed methods are capable of locating faults by using obtained voltage and current measurements at the local substation. Two types of fault location algorithms, using line to neutral and line to line measurements, are presented. The network structure and parameters are assumed to be known. The network structure needs to be updated based on information obtained from utility telemetry system. With the help of bus impedance matrix, local voltage changes due to the fault can be expressed as a function of fault currents. Since the bus impedance matrix contains information about fault location, superimposed voltages at local substation can be expressed as a function of fault location, through which fault location can be solved. Simulation studies have been carried out based on a sample distribution power system. From the evaluation study, it is evinced that very accurate fault location estimates are obtained from both types of methods.

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LEE, T. H., S. S. GE, C. C. HANG, Q. ZHAO, and A. S. AU. "Real-time neural-network-based control of a gyro-mirror line-of-sight stabilization platform." International Journal of Systems Science 29, no. 7 (July 1998): 745–58. http://dx.doi.org/10.1080/00207729808929568.

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Palanichamy, S., and Animesh Biswas. "Frequency-dependent analysis of microstrip-slot coupled line for phase-shifting and impedance-transforming network applications." Microwave and Optical Technology Letters 19, no. 4 (November 1998): 262–67. http://dx.doi.org/10.1002/(sici)1098-2760(199811)19:4<262::aid-mop6>3.0.co;2-i.

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Dashtdar, Majid, and Masoud Dashtdar. "Fault Location in the Transmission Network Based on Extraction of Fault Components Using Wavelet Transform." Scientific Bulletin of Electrical Engineering Faculty 19, no. 2 (October 1, 2019): 1–9. http://dx.doi.org/10.1515/sbeef-2019-0013.

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AbstractIn this paper, a Discrete Wavelet Transform (DWT) has been utilized for processing the current signal in order to fault-location evaluation in network transmission using pre-fault and post-fault current data of both the terminals of a transmission line. In fact, the basis of the work is based on the information recorded before the fault at the end of the line and after the fault at the beginning of the line received by the relay. Obviously, high-frequency components are created at the time of the fault, which is a way of extracting these components using a wavelet transform. In this design, characteristics extorted from synchronous recording of three-phase current signals at the two terminals using DWT. In the following, can accurately estimate the exact location of the fault in the transmission network by extraction and subtracting of the minimum and maximum components of the DWT approximate and detail components of the signal before and after the fault (pre-fault and post-fault). The simulation results reveal that the minimum and maximum extracted components are highly dependent on the fault resistance. Hence, due to increase the fault resistance, the level of signal decomposition has to be increased so that the algorithm is not compromised. Eventually, the proposed method is tested on the transmission network of 735 kV at different distances of the transmission line, which indicates that the proposed algorithm can accurately estimate the fault distance, depending on the type of fault (including low-impedance and high-impedance fault) by changing the signal decomposition level.

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Russer, J. A., F. Mukhtar, A. Baev, Y. Kuznetsov, and P. Russer. "Combined lumped element network and transmission line synthesis for passive microwave structures." Advances in Radio Science 9 (July 29, 2011): 95–98. http://dx.doi.org/10.5194/ars-9-95-2011.

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Abstract. Compact circuit models of electromagnetic structures are a valuable tool for embedding distributed circuits into complex circuits and systems. However, electromagnetic structures with large internal propagation delay are described by impedance functions with a large number of frequency poles in a given frequency interval and therefore yielding equivalent circuit models with a high number of lumped circuit elements. The number of circuit elements can be reduced considerably if in addition to capacitors, inductors, resistors and ideal transformers also delay lines are included. In this contribution a systematic procedure for the generation of combined lumped element/delay line equivalent circuit models on the basis of numerical data is described. The numerical data are obtained by numerical full-wave modeling of the electromagnetic structure. The simulation results are decomposed into two parts representing a lumped elements model and a delay line model. The extraction of the model parameters is performed by application of the system identification procedure to the scattering transfer function. Examples for the modeling of electromagnetic structures are presented.

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Survilo, J. "Application of Apparent Impedance Method at Variable Specific Resistance of Phase Conductor." Latvian Journal of Physics and Technical Sciences 45, no. 1 (March 1, 2008): 25–40. http://dx.doi.org/10.2478/v10047-008-0002-x.

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Application of Apparent Impedance Method at Variable Specific Resistance of Phase ConductorThe apparent impedance to single-phase earth fault place is obtained applying the classical algorithm of distance protection. Thanks to a complex character of this impedance, the expression for the algorithm decomposes into two equations, allowing two unknowns to be calculated: the reactance to a fault place and the fault resistance, provided the faulty phase voltage and current as well as ground current or zero sequence current are known. To do this, a special mathematical procedure called here the apparent impedance method is employed, which implies the use of specific line parameters. For high voltage two-terminal and radial lines of distribution networks the iterative procedure could be applied under the condition that the faulty phase voltage is measured in a distribution network with sufficient precision. Among other specific line parameters, the inconsistency of specific resistance of the phase conductor deserves special attention because of its unpredictable nature and wide range of deviations causing inadmissible errors in distribution networks. To cope with this shortcoming, the temperature of the phase conductor wire should be known at the moment of fault inception. Otherwise, the single-phase earth fault current should be increased to the level above the half the line load current.

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Nakai, Takayoshi. "Simulation of Normal Incidence Sound Absorption Coefficients of Perforated Panels With/Without Glass Wool by Transmission Line Parameters in a Two-Port Network." Rajshahi University Journal of Science and Engineering 44 (November 19, 2016): 123–30. http://dx.doi.org/10.3329/rujse.v44i0.30397.

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This paper describes simulation of normal incidence sound absorption coefficients of perforated panels by transmission line parameters in a two-port network. Maa and Sakagami have investigated micro perforated panels, MPP. But their theories can treat only near 1 % perforation rates of perforated panels with back cavities. If sound propagates as a plane wave, sound propagation can be represented as transmission line parameters in a two-port network. Perforated panels, back cavities, and glass wool absorption materials are represented as matrix of transmission line parameters, respectively. Transmission line parameters of a perforated panel with a back cavity are calculated as multiplication of their matrices. An input impedance can be calculated from the transmission line parameters. A normal incident absorption coefficient is calculated from the input impedance. Holes of the perforated panels have losses of viscous friction and thermal conduction at their walls. Simulations are done in the condition of 0.25 mm to 5 mm diameters of holes, 0.25 % to 25 % perforation rates, 0.5 mm to 5 mm thickness of the perforated panels with back cavities in which there are or are not glass wool absorption materials. The results of these simulations are good agreements with the results of our measurements by transfer function method except in the condition of more than 1 mm diameter of holes.

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Chen, Liang, Heng Nian, and Yunyang Xu. "Impedance Aggregation Method of Multiple Wind Turbines and Accuracy Analysis." Energies 12, no. 11 (May 28, 2019): 2035. http://dx.doi.org/10.3390/en12112035.

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The sequence domain impedance modeling of wind turbines (WTs) has been widely used in the stability analysis between WTs and weak grids with high line impedance. An aggregated impedance model of the wind farm is required in the system-level analysis. However, directly aggregating WT small-signal impedance models will lead to an inaccurate aggregated impedance model due to the mismatch of reference frame definitions among different WT subsystems, which may lead to inaccuracy in the stability analysis. In this paper, we analyze the impacts of the reference frame mismatch between a local small-signal impedance model and a global one on the accuracy of aggregated impedance and the accuracy of impedance-based stability analysis. The results revealed that the impact is related to the power distribution of the studied network. It was found that that the influence of mismatch on stability analysis became subtle when subsystems were balanced loaded. Considering that balanced loading is a common configuration of the practical application, direct impedance aggregation by local small-signal models can be applied due to its acceptable accuracy.

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Gao, Li, and Hong Chun Shu. "Study on a Method of Single – Phase Grounding Fault Locating for Hybrid Transmission Line." Advanced Materials Research 614-615 (December 2012): 1075–80. http://dx.doi.org/10.4028/www.scientific.net/amr.614-615.1075.

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It is difficult to achieve precise fault location for hybrid transmission line of distribution network, because it has wave impedance discontinuity point. Section location is the premises of precise location. On the basis of others’ research results, the matrix algorithm of distribution network single-phase ground fault section location is improved in the paper. It makes the sparse degree of matrix is higher, computation is less. An algorithm of recovery the network topology only based on the fault description matrix is suggested when the visualization data of a line network topology is loss or the operating is in the non-visual condition. The method is applied to revise fault description matrix, so that the matrix algorithm has some fault-tolerance. The applicability and validity of the improved algorithm was verified by an illustration. The method realizes the fault section location, and the subsequent accurate fault location is presented in this paper.

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Al-Tameemi, Mustafa, Yushi Miura, Jia Liu, Hassan Bevrani, and Toshifumi Ise. "A Novel Control Scheme for Multi-Terminal Low-Frequency AC Electrical Energy Transmission Systems Using Modular Multilevel Matrix Converters and Virtual Synchronous Generator Concept." Energies 13, no. 3 (February 8, 2020): 747. http://dx.doi.org/10.3390/en13030747.

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This paper proposes a new control scheme for the low frequency AC transmission (LFAC) system aiming at extending the point-to-point configuration to form a multi-terminal electrical energy network. The multi-terminal low frequency ac (MT-LFAC) system configuration is based on the use of modular multilevel matrix converters (M3Cs) and virtual synchronous generator (VSG) control. The M3C is the next ac/ac converter generation, which is used as an interface with the conventional AC network and the LFAC electrical energy system. Application of VSG control is proposed to enable proper power sharing, to provide synchronization of each terminal, and frequency stabilization, thus, to offer multiterminal forming capability. Two different operation modes are applied in the system to damp the frequency deviation after a dynamic perturbation, which provides additional stabilization feature to the VSG. Frequency restoration mode and commanded mode of power sharing are applied as dynamic states to validate the robustness of the VSG control system. Besides, to solve the negative impact of low X/R ratio in the LFAC electrical energy system, we enhance the VSG control by proposing a virtual-impedance-based solution, which increases the output total impedance on the low frequency side and prevents the coupling between P and Q. The operation of the proposed system is examined by simulation results with a precise model of M3Cs in the PSCAD/ EMTDC software environment (version 4.2.1, Winnipeg, MB, Canada).

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Kim, Phirun, Girdhari Chaudhary, and Yongchae Jeong. "Wide‐stopband and high selectivity step impedance resonator bandpass filter using T‐network and antiparallel coupled line." IET Microwaves, Antennas & Propagation 13, no. 11 (June 12, 2019): 1916–20. http://dx.doi.org/10.1049/iet-map.2018.5947.

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Dashti, Rahman, and Javad Sadeh. "Accuracy improvement of impedance-based fault location method for power distribution network using distributed-parameter line model." International Transactions on Electrical Energy Systems 24, no. 3 (October 25, 2012): 318–34. http://dx.doi.org/10.1002/etep.1690.

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Huang, Yong, Min You Chen, Jin Qian Zhai, and Hong Yan. "High Impedance Fault Identification Method of Distribution Networks." Advanced Materials Research 516-517 (May 2012): 1785–90. http://dx.doi.org/10.4028/www.scientific.net/amr.516-517.1785.

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Abstract. High impedance fault has always been difficult for distribution network fault identification due to its unobvious fault signature and difficult detection. This paper decomposed the transient signal in multi-scale by utilizing the good localization performance of the wavelet in both time domain and frequency domain, reconstructed the wavelet coefficients under each scale, took the wavelet reconstruction coefficient which was under the scale 3, calculated the size spectrum of each feeder line in timing floating window and identified the circuits in which the faults lined according to the value of the size spectrum. The high impedance fault simulation system was built based upon the study of the various transient signals in power systems, and the high impedance fault simulation analysis of the distribution feeder was undertaken through PSCAD simulation platform using high impedance fault model. Simulation analysis showed that the method could effectively extract the feature of high impedance fault on high impedance fault identification.

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Huang, Zhi Chao, Yi Zhong, Cai Lin Li, Mu Liu, and Sheng Zhen Yang. "Study of Earth-Fault Location Method for Distribution Network Based on Transient Signal." Applied Mechanics and Materials 105-107 (September 2011): 742–46. http://dx.doi.org/10.4028/www.scientific.net/amm.105-107.742.

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According to the generating process and propagation characteristics of earth-fault transient signal, an earth-fault location method for distribution network based on transient signal is presented. In the method, in order to change line characteristic impedance, a resonant filter circuit is paralleled in line segment border, so that it could cause transient current energy differences in feature frequency band on both sides of detection device. The location method achieves earth-fault area location through comparing transient current energy and energy attenuation coefficient in feature frequency band. The simulation test result shows that the method isn't influenced by distribution system grounded style, operation style and other factors and which could detect the earth-fault area rapidly and reliably in distribution network and has a high project application value.

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Snyder, Dylan B., Scott A. Beardsley, and Brian D. Schmit. "Role of the cortex in visuomotor control of arm stability." Journal of Neurophysiology 122, no. 5 (November 1, 2019): 2156–72. http://dx.doi.org/10.1152/jn.00003.2019.

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Whereas numerous motor control theories describe the control of arm trajectory during reach, the control of stabilization in a constant arm position (i.e., visuomotor control of arm posture) is less clear. Three potential mechanisms have been proposed for visuomotor control of arm posture: 1) increased impedance of the arm through co-contraction of antagonistic muscles, 2) corrective muscle activity via spinal/supraspinal reflex circuits, and/or 3) intermittent voluntary corrections to errors in position. We examined the cortical mechanisms of visuomotor control of arm posture and tested the hypothesis that cortical error networks contribute to arm stabilization. We collected electroencephalography (EEG) data from 10 young healthy participants across four experimental planar movement tasks. We examined brain activity associated with intermittent voluntary corrections of position error and antagonist co-contraction during stabilization. EEG beta-band (13–26 Hz) power fluctuations were used as indicators of brain activity, and coherence between EEG electrodes was used as a measure of functional connectivity between brain regions. Cortical activity in the sensory, motor, and visual areas during arm stabilization was similar to activity during volitional arm movements and was larger than activity during co-contraction of the arm. However, cortical connectivity between the sensorimotor and visual regions was higher during arm stabilization compared with volitional arm movements and co-contraction of the arm. The difference in cortical activity and connectivity between tasks might be attributed to an underlying visuomotor error network used to update motor commands for visuomotor control of arm posture. NEW & NOTEWORTHY We examined cortical activity and connectivity during control of stabilization in a constant arm position (i.e., visuomotor control of arm posture). Our findings provide evidence for cortical involvement during control of stabilization in a constant arm position. A visuomotor error network appears to be active and may update motor commands for visuomotor control of arm posture.

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Rahman, Akhlaq, and Fred Olinger. "Improvement of Rated Power and VSWR Characteristics for Termination Resistor with Integrated Matching Network and Efficient Thermal Management." International Symposium on Microelectronics 2011, no. 1 (January 1, 2011): 000318–21. http://dx.doi.org/10.4071/isom-2011-tp3-paper6.

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Matching RF and Microwave signals to components within a circuit has become more challenging for circuit designer as operating frequency and power handling requirement increase. Termination resistors with excellent power handling capability with superior voltage standing wave ratio (VSWR) characteristics are needed for microwave circuit components in various wireless and telecommunication application. In this work, we extensively studied to improve the power handling capability and VSWR of termination resistor while maintaining the smaller size. We optimized the energy transmission within the component and significantly improved the efficiency of energy transfer between the transmission lines and the terminations. We discussed techniques of improving power handling capability and reduction of thermal fatigue to the component’s structure. By using innovative techniques of heat transfer we appreciably increased power handling capability while keeping the product size as minimum. We constructed matching network using integrated microstrip line at the beginning of the resistor material. We optimized impedance matching by varying length, width and pattern of transmission line as well as using defective ground structure (DGS) technique. We minimized the detrimental influence of component footprint and resistor material characteristics effect on signal reflection. Considering the necessary microwave parameters and required thermal performance, we designed and manufactured Pb free high power termination resistor. Several sizes of resistor are manufactured with rated power of 20 Watt, and 100 Watt which provides excellent VSWR characteristics for frequency up to 4 GHz. Resistors are manufactured for 50 ohm impedance; however, methods mentioned in the study are applicable to any impedance.

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Gatti, Roberto Vincenti, Riccardo Rossi, and Marco Dionigi. "Broadband Right-Angle Rectangular Waveguide to Substrate Integrated Waveguide Transition with Distributed Impedance Matching Network." Applied Sciences 9, no. 3 (January 23, 2019): 389. http://dx.doi.org/10.3390/app9030389.

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A broadband right-angle rectangular waveguide to substrate integrated waveguide transition for hybrid RWG-SIW (rectangular waveguide–substrate integrated waveguide) feeding networks is presented. The narrower return loss bandwidth issue with respect to in-line configurations is addressed with the introduction of a multi-section matching network consisting of a number of symmetric E-plane irises in the rectangular waveguide section. A hybrid design procedure based on circuit simulation and full-wave optimization is outlined and adopted to synthesize three matching networks with respectively one, two, and three irises, according to the bandwidth to be covered. The design procedure is experimentally validated with a proof-of-concept prototype.

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Park, Changjoo, and Minjae Lee. "An 87% Power-Efficiency Hybrid of Voltage- and Current-Mode Line Driver with an Adaptive Amplitude Tuning." Electronics 10, no. 15 (July 26, 2021): 1785. http://dx.doi.org/10.3390/electronics10151785.

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This brief presents a hybrid of voltage- and current-mode line drivers for the turbo controller area network (CAN). The current-mode scheme prevents signal attenuation caused by source termination resistors, and it enhances signal power efficiency. On top of that, an adaptive amplitude tuning is implemented to mitigate non-linearity and closed-loop gain variations against load impedance variations. The proposed line driver achieves 87.0% power-efficiency and total harmonic distortion, plus noise (THD+N) of −49.0 dB at an input frequency of 40 MHz and output swing of 2.8 VPP differential. The adaptive amplitude tuning allows load impedance variations from 80 Ω to 160 Ω. The total power consumption is 37.6 mW with a 1.8 V supply voltage in 180 nm CMOS, and it occupies 0.377 mm2.

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V, Bindhu, and Ranganathan G. "Effective Automatic Fault Detection in Transmission Lines by Hybrid Model of Authorization and Distance Calculation through Impedance Variation." March 2021 3, no. 1 (March 27, 2021): 36–48. http://dx.doi.org/10.36548/jei.2021.1.004.

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Fault detection in the transmission is a challenging task when examining the accuracy of the system. This fault can be caused by a man-made force or by using concurrent overvoltage in the power distribution line. This research focuses on two sections to handle the power transmission line problem and can be rectified as previously stated. An intelligent approach is utilized for monitoring and controlling line faults in order to improve the accuracy of the equipment in transmission line fault detection. After several iterations of the procedure, the combination of line and master unit improves the system's accuracy and reliability. The master unit identifies faulty poles in the network based on the variation of current and voltage of each node and calculates the distance between the station and the faulty node to reduce manual effort. In the proposed work, many sensors are used to detect the line fault in a network by placing the appropriate point. The pure information can be transferred to an authorized person or unit after many iterations due to knowledgeable devices. The faulty status of the pole information is displayed in the control unit by a display unit comprised of an alarm unit to alert the corresponding section using ZigBee techniques. The GSM unit provides the faulty status of an authorized person to rectify the problems immediately which further improve the reliability of the system. When compared to existing methods, our hybrid proposed method achieves a higher accuracy of 90%. This method aids to reduce the labor costs gradually to visit all-pole points instead of faulty pole points and thereby increasing the reliability of the electrical consumers.

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Gu, Song Lin, and Zeng Ping Wang. "A Fast Searching Scheme for Power Flow Transferring Identification in Complex Power Grid." Advanced Materials Research 732-733 (August 2013): 789–95. http://dx.doi.org/10.4028/www.scientific.net/amr.732-733.789.

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Power flow transferring random occurred in power grid, so how to quickly identify overload line is a key problem to prevent cascading trips. This paper according to the bus self-impedance change rate rapid search the area which possible happened power flow transferring, and through the correction method for network equations checked the lines in this area whether overload or not, then selected the overload line caused by power flow transferring. Under the condition of known initial network parameters, this scheme according to the local network parameters modified to related calculation, improves the calculation speed, and has advantages for multipoint flow transferring recognition in complex power grid. Taking the New England 10-unit 39-bus system which also used this method as the example, in this case, this method is confirmed by the BPA simulation.

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Sánchez-Moctezuma, Elvia-Andrea, Laura-Jaqueline Santander-Hernández, Fernanda Álvarez-Mendoza, and César Angeles-Camacho. "Real-Time Analysis of the Impedance–Temperature Relationship in Electric Distribution Lines Using PMUs." Energies 14, no. 6 (March 17, 2021): 1661. http://dx.doi.org/10.3390/en14061661.

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In this paper, an efficient method to compute the phase impedance of a power distribution line is presented. This paper’s main interest is to collect and analyze the impedance–temperature profiles in distribution lines by employing real-time phasor measurement units (PMUs) voltage and current measurements. The monitoring system has been developed for microgrids integrating ocean energies within the scope of the Mexican Ocean Energy Innovation Centre (CEMIE-Océano), contributing to marine energy tools’ innovation and development. The development tool can easily be applied to other distribution network components or to monitor microgrids with renewable-energy generation.

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Journal articles on the topic 'Line impedance stabilization network'

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