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Journal articles on the topic 'Negative sequence current'

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Author: Grafiati

Published: 10 December 2022

Last updated: 28 January 2023

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1

Medeiros de Souza Azevedo, Gustavo, Joan Rocabert, Marcelo Cabral Cavalcanti, Francisco de Assis dos Santos Neves, and Pedro Rodríguez. "A Negative-sequence Current Injection Method To Mitigate Voltage Imbalances In Microgrids." Eletrônica de Potência 16, no. 4 (November 1, 2011): 296–303. http://dx.doi.org/10.18618/rep.20114.296303.

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2

Mochinaga, Yoshifumi, Yuji Ishii, Masuo Goto, and Tomoharu Nakamura. "Static Negative-Phase-Sequence Current Compensator." IEEJ Transactions on Power and Energy 112, no. 7 (1992): 629–34. http://dx.doi.org/10.1541/ieejpes1990.112.7_629.

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3

Kozlov, Alexander Nikolaevich, Vitaly Alexandrovich Kozlov, and Tatyana Sergeevna Kozlova. "SIMULATION OF A NEGATIVE SEQUENCE CURRENT TRANSDUCER." Messenger AmSU, no. 97 (2022): 66–73. http://dx.doi.org/10.22250/20730268_2022_97_66.

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4

Farughian, Kumpulainen, and Kauhaniemi. "Earth Fault Location Using Negative Sequence Currents." Energies 12, no. 19 (September 30, 2019): 3759. http://dx.doi.org/10.3390/en12193759.

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In this paper, a new method for locating single-phase earth faults on non-effectively earthed medium voltage distribution networks is proposed. The method requires only current measurements and is based on the analysis of the negative sequence components of the currents measured at secondary substations along medium voltage (MV) distribution feeders. The theory behind the proposed method is discussed in depth. The proposed method is examined by simulations, which are carried out for different types of networks. The results validate the effectiveness of the method in locating single-phase earth faults. In addition, some aspects of practical implementation are discussed. A brief comparative analysis is conducted between the behaviors of negative and zero sequence currents along a faulty feeder. The results reveal a considerably higher stability level of the negative sequence current over that of the zero sequence current.

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5

Wang, Kai, and Wen Jin Dai. "Research on Negative-Sequence Electric Current Examination Method." Advanced Materials Research 179-180 (January 2011): 1429–34. http://dx.doi.org/10.4028/www.scientific.net/amr.179-180.1429.

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This paper based on traditional ip, iq examination's method , introduces one kind of non-phase-locked loop's ip, iq method. this method avoids the mains frequency displacement the influence, causes the examination to be more conveniently. With the MATLAB simulation of software, obtain the satisfactory results, thus proving the usefulness of this method.

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6

Ohura, Y., T. Matsuda, M. Suzuki, F. Andow, Y. Kurosawa, and A. Takeuchi. "A digital distance relay using negative sequence current." IEEE Transactions on Power Delivery 5, no. 1 (1990): 79–84. http://dx.doi.org/10.1109/61.107259.

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7

Castillo, Silvia Oviedo, and Jabid Quiroga Méndez. "On the Use of Positive Sequence Current / Negative Sequence Current Ratio for Fault Detection in Induction Motors." Revista EIA 16, no. 31 (January 21, 2019): 43–56. http://dx.doi.org/10.24050/reia.v16i31.760.

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This paper studied the use of a new stator current feature for detection of winding and cage bars faults in an induction motor, and presents the experimental validation of a detection and identification scheme using Support Vector Machines (SVM). This validation was performed in a test bed using 2 HP, 4 pole motors in which shorted winding and broken bars faults were induced, separately. Both time and frequency domain features like arithmetic mean, RMS value, Central Frequency, Kurtosis, RMS value of Power Spectral Density were assessed and validated using experimental data for several load conditions. PSC/NSC (positive sequence current/ negative sequence current) ratio was successful in most of the classifiers despite the load regime. This new feature was evaluated in terms of fault detection and severity discrimination with satisfactory results.

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8

Ge, Bao-jun, Wu Guo, Jian Guo, Yun-peng Gao, and Ming-ze Li. "Improvement of the transient negative-sequence rating formula for large generators based on the negative-sequence current component." International Transactions on Electrical Energy Systems 26, no. 3 (May 20, 2015): 539–54. http://dx.doi.org/10.1002/etep.2093.

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9

Najafi, Foad, Mohsen Hamzeh, and Matthias Fripp. "Unbalanced Current Sharing Control in Islanded Low Voltage Microgrids." Energies 11, no. 10 (October 16, 2018): 2776. http://dx.doi.org/10.3390/en11102776.

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This paper reports a new control strategy to improve sharing of unbalanced currents in islanded LV microgrids. This technique provides fast and effective sharing of positive-, negative- and zero-sequence currents, and is the first example of zero-sequence current sharing in the literature. The controllers are designed in the stationary frame. The control structure consists of four loops: (1) the current controller; (2) the voltage controller; (3) the droop controller and the (4) negative and zero sequence current controllers. The output current is considered unknown for the controller and is added to the control system as a disturbance. The proposed controller features a high gain in fundamental and harmonic frequencies, hence a good voltage quality is obtained in the presence of unbalanced and nonlinear loads. To this aim, a proportional-resonant (PR) controller is adopted as the current controller. By using a multi-resonant controller as current controller, a unified control structure is obtained which is suitable for both grid-connected and islanded modes. The voltage controller is designed using a resonant controller so that the voltage can have low VUF and THD in the presence of unbalanced and nonlinear loads. Furthermore, in this paper, the droop method is applied to the control structure to share real and reactive powers. Simulation studies show that the conventional droop method cannot share the oscillatory part of the output power that is due to the presence of unbalanced loads in the microgrid. This paper relies on using zero and negative sequence virtual impedance controller to share the oscillatory part of output power. By using zero-sequence virtual impedance controller (ZSVIC) and negative-sequence virtual impedance controller (NSVIC), the zero and negative sequence currents in the microgrid are controlled and shared effectively. By compensating zero- and negative-sequence currents locally, the flow of these currents in the microgrid is minimized, and the overall power quality of the islanded LV microgrid is improved.

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10

Moriyasu, Shoji. "Effects of DC-Current for Short-Time Negative Sequence Current of Synchronous Machine." IEEJ Transactions on Industry Applications 121, no. 5 (2001): 614–15. http://dx.doi.org/10.1541/ieejias.121.614.

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11

Kai, Takaaki, Mitsuhiro Furuse, Takayuki Matsuda, Motonobu Yoshikawa, Yoshiaki Okazue, and Takashi Kurida. "Negative-phase-sequence load current tolerable new balance ground relaying." IEEJ Transactions on Power and Energy 109, no. 11 (1989): 491–98. http://dx.doi.org/10.1541/ieejpes1972.109.491.

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12

Liao, Tian Fa, Chun Yang Yi, Zhao Quan Cai, Chang Wen Dong, Wei Shi, and Jia Xiang Xue. "Study on LVRT Decoupling Dual Synchronous Current Controller." Applied Mechanics and Materials 668-669 (October 2014): 532–39. http://dx.doi.org/10.4028/www.scientific.net/amm.668-669.532.

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Under three-phase grid asymmetric fault conditions, use traditional PI controller of PV inverters to inject symmetric current positive sequence into the grid, ignoring the impact of the negative sequence current on LVRT, thus traditional PI controller does not apply to three-phase grid asymmetric faults. The paper proposes the decoupling dual synchronous current controller to reject positive, negative sequence current into the grid simultaneously and adopt positive and negative sequence flexible control to determine the active current reference and reactive current reference, avoiding the various drawbacks such as power control, totally positive sequence control bringing. Experiment verify the science and feasibility that decoupling dual synchronous current controller applies to asymmetric faults riding-through.

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13

Karimi, Houshang, Aboutaleb Haddadi, Masoud Karimi-Ghartemani, and Mahdieh Sadabadi. "A Robust Vector Current Controller with Negative-Sequence Current Capability for Grid-Connected Inverters." Energies 14, no. 15 (July 27, 2021): 4549. http://dx.doi.org/10.3390/en14154549.

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This paper presents a vector current controller (in the synchronous reference, or the dq, frame) with negative-sequence current injection capability for three-phase grid-connected converters. This capability is desired for the operation of the converter during unbalanced conditions and also for a certain type of islanding detection. The proposed controller first determines the double-frequency current references and then uses a sixth-order two-input two-output proportional-integral-resonance (PIR) structure, which is optimally designed. Compared with the existing similar approaches, the proposed controller has a simpler structure and more robust performance, e.g., against system parameter uncertainties and weak grid conditions. The proposed controller is developed for converters with both the L-type and LCL-type filters. For the LCL-type converter, a suboptimal partial state feedback control is also proposed to achieve robust stability and active damping of resonance poles without requiring additional sensors. Detailed experimental results are presented to illustrate the properties and performances of the proposed controller.

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14

Takase, Fuyuto, Takanobu Asakura, Takashi Hikihara, Toshiro Matsumura, and Yoshisuke Ueda. "Induction of Zero-Phase-Sequence Voltage by Negative-Phase-Sequence Current in a Synchronous Generator." IEEJ Transactions on Industry Applications 113, no. 3 (1993): 381–86. http://dx.doi.org/10.1541/ieejias.113.381.

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15

Hatano, Nobuhiko, and Toshifumi Ise. "Control Scheme of Cascaded H-Bridge STATCOM Using Zero-Sequence Voltage and Negative-Sequence Current." IEEE Transactions on Power Delivery 25, no. 2 (April 2010): 543–50. http://dx.doi.org/10.1109/tpwrd.2009.2035221.

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16

Quiroga, Jabid E. "Stator winding short-circuit fault detection in a permanent magnet synchronous motor (PMSM) using negative sequence current in time domain." Ingeniería e Investigación 29, no. 2 (May 1, 2009): 48–52. http://dx.doi.org/10.15446/ing.investig.v29n2.15160.

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A negative sequence analysis in time domain was applied to fault detection of permanent magnet synchronous motors (PMSM). The fundamental components of the motor terminal currents were obtained using a Notch filter, based on which the negative sequence components in time domain were then calculated; the negative sequence current constituted the stator winding short-circuit fault indicator. The negative sequence current also provided a qualitative evaluation regarding the severity of the fault. The proposed method promptly (< 22 ms) and reliably determined the stator winding short for different levels of severity in faults around and greater than 6.25% of the shorted phase. Experimental studies confirmed the proportional relationship between fault indicator and the level of severity. Using negative sequence current in time domain reduced computational cost and detection time compared to that in frequency domain. The proposed method could be extended to detect the shorted phase to improve monitoring. The method was validated online using a PMSM experimental setup with dSPACE and Matlab/Simulink environment.

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17

Kumar, Jitendra, and Premalata Jena. "Fault Detection During Asymmetrical Power Swing Using Superimposed Negative Sequence Current." Arabian Journal for Science and Engineering 44, no. 8 (February 18, 2019): 7033–46. http://dx.doi.org/10.1007/s13369-019-03768-z.

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18

Aparecida Pereira Beneteli, Tatianna, Debora Rosana Ribeiro Penido, and Leandro Ramos Araujo. "A Method to Reduce the Negative Sequence Current in Electrical Equipments." IEEE Latin America Transactions 14, no. 12 (December 2016): 4699–705. http://dx.doi.org/10.1109/tla.2016.7817000.

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19

Romaniuk, F. A., V. Yu Rumiantsev, Yu V. Rumiantsev, A. A. Dziaruhina, and P. I. Klimkovich. "Researching the Blocking of Current Protection of Electrical Power Units with Transformers." ENERGETIKA. Proceedings of CIS higher education institutions and power engineering associations 63, no. 6 (December 2, 2020): 491–99. http://dx.doi.org/10.21122/1029-7448-2020-63-6-491-499.

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The magnetizing current inrush appears in electrical power units equipped with transformers in case of no-load energizing of the power transformers and in a number of other cases. This phenomenon could cause a false triggering of the current protection. To prevent incorrect actions of the current protection during the magnetizing current inrush a protection blocking is carrying out. The blocking principle operation is based on the fact that in a three-phase system in normal mode and in case of symmetrical short circuit the first harmonics contained in the phase currents of electrical installations form a direct sequence and the second ones – the negative sequences. In case of an asymmetric mode, including an asymmetric short circuit, the negative sequence appears, formed by the first harmonics that are part of the phase currents of the specified system. In magnetizing current inrush modes, second harmonics of significant magnitude are present in phase currents, which form the negative sequence. Based on the analysis of the information parameters of the specified sequences currents, identification of the magnetizing current inrush and short-circuit modes is performed with the implementation of the protection blocking if necessary. The study of the current protection blocking functioning was performed using computational experiment by analyzing the calculated changes of blocking parameter compared with the threshold setpoint. The specified researching is done by using the digital model that is implemented in the dynamic modeling environment MatLab-Simulink. As a result of the performed calculations, the principal operability of the proposed current protection blocking was confirmed that provides a fairly reliable identification of the magnetizing current inrush and short-circuits modes, regardless of the degree of saturation of current transformers. It was found that the proposed principle of the current protection blocking has a higher sensitivity in comparison with the classical one based on the estimation of the ratio of the second and first harmonics of the phase currents. In short-circuit modes in an electrical power units the proposed blocking causes a current protection operation delay that can be reduced by digital filters performance improvement.

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20

Fu, Pengwu, Dongwen Yang, Zhi He, Zhenfeng Duan, and Dengmei Wang. "Practical calculation of asymmetric short circuit current of DFIG connected to distribution network." E3S Web of Conferences 145 (2020): 02075. http://dx.doi.org/10.1051/e3sconf/202014502075.

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In view of the existing complex analytic calculations of DFIG short-circuit current are hardly applied in engineering projects, a practical calculation of asymmetric short-circuit current of DFIG is proposed. According to the complex sequence and their Thevenin equivalent model of DFIG network, the composition of each sequence component of DFIG short-circuit current is analysed. Moreover, considering the low-voltage ride through strategy of DFIG, the negative sequence periodic components of short circuit current are well analysed during the crowbar activation and deactivation, and the formula of the negative sequence periodic components of short circuit current are derived. On the basis of positive and negative sequence open circuit voltage, calculating impedance and rotor current, the judgement of crowbar activation is established. The pre-calculated surfaces of negative sequence periodic components of short circuit current are proposed, and the procedure for calculating the asymmetric short-circuit current of DFIG is designed. Finally, the proposed method is verified by simulation.

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21

Farughian, Amir, Lauri Kumpulainen, and Kimmo Kauhaniemi. "Non-Directional Earth Fault Passage Indication in Isolated Neutral Distribution Networks." Energies 13, no. 18 (September 11, 2020): 4732. http://dx.doi.org/10.3390/en13184732.

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In this paper, two new methods for locating single-phase to ground faults in isolated neutral distribution networks are proposed. The methods are based on the analysis of symmetrical sequence currents. They are solely based on currents, not requiring voltage measurement. The first method employs only the zero sequence current and the second one utilizes the negative sequence current in combination with the zero sequence current. It is revealed why using only zero sequence current with a simple threshold is insufficient and may lead to false results. Using the proposed methods, earth faults with high resistances can be located in isolated neutral distribution networks with overhead lines or cables.

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22

Villén, María Teresa, Maria Paz Comech, Eduardo Martinez Carrasco, and Aníbal Antonio Prada Hurtado. "Influence of Negative Sequence Injection Strategies on Faulted Phase Selector Performance." Energies 15, no. 16 (August 19, 2022): 6018. http://dx.doi.org/10.3390/en15166018.

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Renewable power is expected to increase drastically in the coming years due to the energy transition. A large part of the newly installed generators will be connected to the power system through inverters and electronic converters, whose behaviour differs from the generators connected synchronously to the network. One of the main differences is the current contribution during symmetrical and asymmetrical faults which can affect protection systems. New grid codes establish requirements for fast current injection, but the converter’s maximum current limitations during faults make it difficult to establish control strategies for such current contribution. This paper studies the performance of faulted phase selector algorithm of a commercial relay under the current contribution from renewables before unbalanced faults. Two positive and negative sequence current injection strategies in compliance with new Spanish grid code requirements are proposed and tested under fault conditions in HiL (Hardware in the Loop). Test results show that the selected injection strategy affects the fault phase identification algorithm. Furthermore, the negative sequence injection requirements established in the new grid code improve the relay performance when line-to-line faults are applied, but they are not enough to identify all fault types.

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23

Bakhri, Syaiful, and Nesimi Ertugrul. "A Negative Sequence Current Phasor Compensation Technique for the Accurate Detection of Stator Shorted Turn Faults in Induction Motors." Energies 15, no. 9 (April 24, 2022): 3100. http://dx.doi.org/10.3390/en15093100.

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Stator faults are the most critical faults in induction motors as they develop quickly hence requiring fast online diagnostic methods. A number of online condition monitoring techniques are proposed in the literature to respond to such faults, including the signature analysis of the stator current, vibration monitoring, flux leakage monitoring, negative sequence components of voltage and current and sequence components monitoring based on the identification of asymmetrical behavior in a machine. Negative sequence components of voltage and current and sequence components monitoring are commonly considered for the identification of asymmetrical behavior of induction motors. Negative sequence current analysis is a sensitive technique for the detection of shorted turns as it directly measures the asymmetry produced by the fault. However, the technique is sensitive to other asymmetrical faults and disturbances, which can also produce negative sequence currents. These disturbances include sensor errors, inherent asymmetry and voltage unbalance. This paper provides a comprehensive investigation of the disturbances using a motor model along with experimental measurements under varying load conditions. Then, a new phasor compensation technique is explained to eliminate such disturbances effectively. This technique enables the accurate detection of even relatively small shorted turn faults, even at an early stage. The technique is tested experimentally, and a set of practical results are given to validate the methods developed.

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24

ŠKUMÁT, Tomáš. "Negative Sequence Current as a Breaker Failure Protection for Medium Voltage Grids." PRZEGLĄD ELEKTROTECHNICZNY 1, no. 11 (November 2, 2021): 138–45. http://dx.doi.org/10.15199/48.2021.11.25.

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25

Wang, Yong, Zhicheng Deng, Jiaying Chen, and Di Wang. "Research on Life Loss of Generator Retainer Caused by Negative Sequence Current." Journal of Physics: Conference Series 2132, no. 1 (December 1, 2021): 012043. http://dx.doi.org/10.1088/1742-6596/2132/1/012043.

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Abstract With a large number of wind and solar power sources connected to the power grid, higher requirements are put forward for the power generation equipment to respond to the power grid imbalance. The safety research of generator rotor retaining ring under the impact of negative sequence current is of great significance. For 300MW turbogenerator, the two-dimensional and three-dimensional eddy current, temperature rise, stress and life of generator rotor under the impact of negative sequence current are analyzed and studied. The two-dimensional calculation models of stator and rotor are established, and the distribution of negative sequence eddy current field in rotor section is analyzed; considering the contact resistance between rotor and retaining ring and the end effect of magnetic field, a three-dimensional analysis model is established, and the calculation results of three-dimensional eddy current field, temperature field and stress field are obtained. The analysis shows that after considering the contact resistance between rotor and retaining ring and end effect, the current density at the contact between retaining ring and rotor big tooth edge is 17.6 times of the two-dimensional calculation result of rotor section, and the maximum temperature of rotor retaining ring reaches 170.36°C.

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26

Ho, Ping-heng, Chi-jui Wu, Chung-liang Chang, and Yuin-hong Liu. "Reassessment of Permissible Negative Sequence Current for Power Plant Operation of Taipower." Energy and Power Engineering 02, no. 04 (2010): 271–82. http://dx.doi.org/10.4236/epe.2010.24039.

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27

Chen, Jen-Hung, Wei-Jen Lee, and Mo-Shing Chen. "Use of a static var compensator for generator negative-sequence current reduction." Electric Power Systems Research 38, no. 3 (September 1996): 183–90. http://dx.doi.org/10.1016/s0378-7796(96)01083-8.

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28

Kuwabara, Kento, and Hiroaki Kakigano. "DC Capacitor Voltage Control of MMC for HVDC using Negative Sequence Current." Journal of the Japan Institute of Power Electronics 43 (March 31, 2017): 89–96. http://dx.doi.org/10.5416/jipe.43.89.

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29

Chaudhary, S. K., R. Teodorescu, P. Rodriguez, P. C. Kjaer, and A. M. Gole. "Negative Sequence Current Control in Wind Power Plants With VSC-HVDC Connection." IEEE Transactions on Sustainable Energy 3, no. 3 (July 2012): 535–44. http://dx.doi.org/10.1109/tste.2012.2191581.

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30

Peres, Larissa M., and Kleber M. Silva. "Power transformer protection using an instantaneous-current-value negative sequence differential element." International Journal of Electrical Power & Energy Systems 108 (June 2019): 96–106. http://dx.doi.org/10.1016/j.ijepes.2018.12.033.

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31

Burgund, Davorin, and Srete Nikolovski. "Improved Model of Thermal Rotor Protection Including Negative Sequence Protection." Energies 15, no. 7 (March 24, 2022): 2391. http://dx.doi.org/10.3390/en15072391.

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The paper presents a new model of the thermal rotor protection 49R on synchronous generators with self-excitation with the influence of generator negative sequence protection 46I2. The purpose of the analysis is to solve the problem of simultaneous occurrence of rotor overload due to excitation current and rotor overload due to the inverse component of the stator current. The numerical protections are designed to operate independently of each other, and therefore the residual thermal capacity of the copper windings is not defined with higher precision. A mathematical model that integrates these two protections is given and described.

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32

Liu, Hui Zhi, Xu Hong Wang, Kun Yang Wang, and Ju Xiang Feng. "An Induction Motor Stator Core Fault Model Based on Stator Negative Sequence Current." Applied Mechanics and Materials 203 (October 2012): 406–10. http://dx.doi.org/10.4028/www.scientific.net/amm.203.406.

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An on-line method is proposed in this work to detect induction motor stator core fault by using stator negative sequence current. According to the existing abc coordinate model, a new equivalent circuit is obtained. In this circuit, the stator core loss each phase in normal state is modeled as core loss resistance symmetrically distributed among the three phases. The stator core loss is increased and is asymmetrically distributed among the three phases when a stator fault happens. The positive, negative and zero sequence equivalent circuits are drawn by a series of analysis of the circuit put forward above. It is demonstrated that there is a good correlation between stator core fault severity and the magnitude of the negative sequence current.

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33

Liang, Jian, Shuang Zhang, Yong Ren, and Yuanchu Cheng. "Harmonics Current Detection in Three-phase Circuit using Neural Network." Journal of Physics: Conference Series 2242, no. 1 (April 1, 2022): 012043. http://dx.doi.org/10.1088/1742-6596/2242/1/012043.

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Abstract Harmonics seriously affect the safety and economy of power system. In order to control harmonics effectively, harmonic current and harmonic power must be detected quickly. Based on the analysis of the components of three-phase nonlinear current, a neural network detection method of fundamental and harmonic current in three-phase circuit is proposed. The method uses a neural network instead of the low-pass filter in the instantaneous reactive power theory. The example results show that the proposed method has the advantages of less computation, better real-time performance and high detection accuracy. The method can be used to detect the positive-sequence (negative-sequence) fundamental active current, positive-sequence (negative-sequence) fundamental reactive current, harmonic, distortion current and harmonic power.

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34

Ekic, Almir, Di Wu, and John N. Jiang. "Impact of Solar Inverter Dynamics during Grid Restoration Period on Protection Schemes Based on Negative-Sequence Components." Energies 15, no. 12 (June 15, 2022): 4360. http://dx.doi.org/10.3390/en15124360.

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The growing penetration of renewable resources such as wind and solar into the electric power grid through power electronic inverters is challenging grid protection. Due to the advanced inverter control algorithms, the inverter-based resources present fault responses different from conventional generators, which can fundamentally affect the way that the power grid is protected. This paper studied solar inverter dynamics focused on negative-sequence quantities during the restoration period following a grid disturbance by using a real-time digital simulator. It was found that solar inverters can act as negative-sequence sources to inject negative-sequence currents into the grid during the restoration period. The negative-sequence current can be affected by different operating conditions such as the number of inverters in service, grid strength, and grid fault types. Such negative-sequence responses can adversely impact the performance of protection schemes based on negative-sequence components and potentially cause relay maloperations during the grid restoration period, thus making system protection less secure and reliable.

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35

Shamseh, Mohammad Bani, Ruben Inzunza, and Tatsuaki Ambo. "A Novel Islanding Detection Technique Based on Positive-Feedback Negative Sequence Current Injection." IEEE Transactions on Power Electronics 37, no. 7 (July 2022): 8611–24. http://dx.doi.org/10.1109/tpel.2022.3146342.

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36

BENHADJ AMMAR, Akram, Yasser GRITLI, and Mohamed BENREJEB. "Diagnosis of Stator Asymmetry in Permanent Magnet Synchronous Motors Using Negative Sequence Current." Studies in Informatics and Control 27, no. 2 (January 7, 2019): 165–74. http://dx.doi.org/10.24846/v27i2y201804.

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37

Jena, P., and A. K. Pradhan. "Directional Relaying During Single-Pole Tripping Using Phase Change in Negative-Sequence Current." IEEE Transactions on Power Delivery 28, no. 3 (July 2013): 1548–57. http://dx.doi.org/10.1109/tpwrd.2013.2258687.

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38

Karimi, Houshang, Amirnaser Yazdani, and Reza Iravani. "Negative-Sequence Current Injection for Fast Islanding Detection of a Distributed Resource Unit." IEEE Transactions on Power Electronics 23, no. 1 (January 2008): 298–307. http://dx.doi.org/10.1109/tpel.2007.911774.

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39

Hamzeh, Mohsen, Houshang Karimi, and Hossein Mokhtari. "Harmonic and Negative-Sequence Current Control in an Islanded Multi-Bus MV Microgrid." IEEE Transactions on Smart Grid 5, no. 1 (January 2014): 167–76. http://dx.doi.org/10.1109/tsg.2013.2263842.

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40

Bouzid, M. Ben Khader, G. Champenois, and S. Tnani. "Reliable stator fault detection based on the induction motor negative sequence current compensation." International Journal of Electrical Power & Energy Systems 95 (February 2018): 490–98. http://dx.doi.org/10.1016/j.ijepes.2017.09.008.

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41

Yang, Shaobing, Xue Li, Kejian Song, and Mingli Wu. "A novel modeling approach of negative-sequence current for electrified railway traction substation." International Journal of Electrical Power & Energy Systems 107 (May 2019): 462–71. http://dx.doi.org/10.1016/j.ijepes.2018.12.004.

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42

Zhu, Chu, and Yong Sheng Li. "Research on a Novel Balance Transformer with Asymmetrical Windings." Advanced Materials Research 915-916 (April 2014): 1149–52. http://dx.doi.org/10.4028/www.scientific.net/amr.915-916.1149.

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For problems of zero sequence current and negative sequence current of traction transformer in Electrified Railway, a novel balance transformer with asymmetrical windings was presented. By a systematic analysis method based on the magnetic force balance equations, winding connection equations, output-port equations and voltage transfer equations, the current relationships of the primary windings and secondary windings and the balance condition were deduced. Through the experimental model of balance transformer in simulation platform based on Matlab/Simulink, the electric characteristics of balance transformer and change law of zero sequence current and negative sequence current in different mode were researched. Through the simulation experiment, the theoretical analysis of correctness and feasibility are verified.

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Cheng, Peng, Chao Wu, Huiwen Kong, Frede Blaabjerg, and Yu Quan. "Connection and Control Strategy of PV Converter Integrated into Railway Traction Power Supply System." Energies 13, no. 22 (November 16, 2020): 5989. http://dx.doi.org/10.3390/en13225989.

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In order to supply the single-phase locomotive load and mitigate the negative sequence current, this paper develops a V/V transformer-based connection and control strategy of three-phase photovoltaic (PV) converters integrated into railway traction power supply systems. In this V/V transformer-based connection, the two-phase traction voltage is converted into the three-phase voltage. This approach can offer a common low voltage AC bus, which is more convenient for more access to three-phase PV converters. Based on this V/V transformer-based connection, an individual phase current control strategy with the hybrid current reference is fully designed. In this control strategy, the current reference, containing two parts, is generated. One is the asymmetrical part for powering the single-phase locomotive load and mitigating the negative sequence current. The other is the symmetrical part for feeding the surplus power back to the utility grid. Then, each phase current replaces the dual-sequence current to be controlled to track the corresponding phase current reference. Consequently, PV converters can flexibly inject the symmetrical and asymmetrical currents without the dual-sequence extraction for a simpler implementation. Finally, the effectiveness of the developed connection and control strategy is validated by the simulation studies.

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Li, Dan, and Ting Ting Cai. "Control Strategy for VSC-HVDC under Unbalanced Grid Voltages." Applied Mechanics and Materials 863 (February 2017): 214–19. http://dx.doi.org/10.4028/www.scientific.net/amm.863.214.

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This paper describes the use of an unbalanced control strategy to solve the faults occur in AC grid side of High voltage direct current based on Voltage Source Converter (VSC-HVDC) system. This method divides the voltage and current parameters into negative-sequence and positive-sequence. It can be obtained that the negative-sequence appears as double-frequency component in the positive-sequence synchronous reference frame; while, it appears as dc component in the negative-sequence synchronous reference frame. To mitigate the unfavourable impact of the unbalance fault, such as the DC link ripples, the dual vector control algorithm in dq synchrounous reference frame is designed. Simulation results demonstrate the validity and the effectiveness of the proposed control scheme.

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Gnaciński, Piotr, Damian Hallmann, Piotr Klimczak, Adam Muc, and Marcin Pepliński. "Effects of Negative Sequence Voltage Subharmonics on Cage Induction Motors." Energies 15, no. 23 (November 22, 2022): 8797. http://dx.doi.org/10.3390/en15238797.

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In some power systems, voltage waveforms contain, apart from harmonics, interharmonics and subharmonics that are components of frequency less than or not an integer multiple of the fundamental frequency. Voltage subharmonics and interharmonics may be of both a positive and negative sequence, independently of their frequency. Previous papers on induction motors under subharmonics have been generally limited to the components of a positive sequence. This study deals with the effect of negative sequence subharmonics on the work of induction motors. Investigations were performed using the 2D finite element method and an experimental method. Differences between the impact of positive and negative sequence subharmonics are discussed. It was found that negative sequence voltage subharmonics can result in significant current subharmonics, torque pulsations and vibration. Further, because of possible resonance, motors that are comparatively resistant to positive sequence subharmonics might be especially sensitive to negative sequence subharmonics of the same frequency and vice versa.

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Cornelissen, Cynthia Nau, James E. Anderson, Ian C. Boulton, and P. Frederick Sparling. "Antigenic and Sequence Diversity in Gonococcal Transferrin-Binding Protein A." Infection and Immunity 68, no. 8 (August 1, 2000): 4725–35. http://dx.doi.org/10.1128/iai.68.8.4725-4735.2000.

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ABSTRACT Neisseria gonorrhoeae is a gram-negative pathogen that is capable of satisfying its iron requirement with human iron-binding proteins such as transferrin and lactoferrin. Transferrin-iron utilization involves specific binding of human transferrin at the cell surface to what is believed to be a complex of two iron-regulated, transferrin-binding proteins, TbpA and TbpB. The genes encoding these proteins have been cloned and sequenced from a number of pathogenic, gram-negative bacteria. In the current study, we sequenced four additional tbpA genes from other N. gonorrhoeaestrains to begin to assess the sequence diversity among gonococci. We compared these sequences to those from other pathogenic bacteria to identify conserved regions that might be important for the structure and function of these receptors. We generated polyclonal mouse sera against synthetic peptides deduced from the TbpA sequence from gonococcal strain FA19. Most of these synthetic peptides were predicted to correspond to surface-exposed regions of TbpA. We found that, while most reacted with denatured TbpA in Western blots, only one antipeptide serum reacted with native TbpA in the context of intact gonococci, consistent with surface exposure of the peptide to which this serum was raised. In addition, we evaluated a panel of gonococcal strains for antigenic diversity using these antipeptide sera.

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Jayanthi, S., Edwin Xavier S. Arockia, R. Renugadevi, and P. S. Manoharan. "Islanding and Non-Islanding Detection for Grid Connected Distribution System." Applied Mechanics and Materials 573 (June 2014): 696–701. http://dx.doi.org/10.4028/www.scientific.net/amm.573.696.

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In this paper, wavelet transform based approach is proposed for islanding detection in a distribution system. The negative sequence voltage and negative sequence current obtained due to disturbances are measured at the point of common coupling (PCC) and given to the wavelet processing module to extract features like standard deviation and energy content. The negative sequence voltage and current components are decomposed under various levels to filter out lower frequency components. From the obtained features suitable threshold value is fixed for classifying the islanding and non-islanding events.

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Wang, Xiaosheng, Ke Dai, Xinwen Chen, Xin Zhang, Qi Wu, and Ziwei Dai. "Reactive Power Compensation and Imbalance Suppression by Star-Connected Buck-Type D-CAP." Energies 12, no. 10 (May 18, 2019): 1914. http://dx.doi.org/10.3390/en12101914.

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Reactive power and negative-sequence current generated by inductive unbalanced load will not only increase line loss, but also cause the malfunction of relay protection devices triggered by a negative-sequence component in the power grid, which threatens the safe operation of the power system, so it is particularly important to compensate reactive power and suppress load imbalance. In this paper, reactive power compensation and imbalance suppression by a three-phase star-connected Buck-type dynamic capacitor (D-CAP) under an inductive unbalanced load are studied. Firstly, the relationship between power factor correction and imbalance suppression in a three-phase three-wire system is discussed, and the principle of D-CAP suppressing load imbalance is analyzed. Next, its compensation ability for negative-sequence currents is determined, which contains theoretical and actual compensation ability. Then an improved control strategy to compensate reactive power and suppress imbalance is proposed. If the load is slightly unbalanced, the D-CAP can completely compensate the reactive power and negative-sequence currents. If the load is heavily unbalanced, the D-CAP can only compensate the positive-sequence reactive power and a part of the negative-sequence currents due to the limit of compensation ability. Finally, a 33 kVar/220 V D-CAP prototype is built and experimental results verify the theoretical analysis and control strategy.

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Li, Yong Sheng, Yi Fa Sheng, Kai Yi Zhang, and Bo Fan. "Research on Electrical Characteristics of a Novel Balance Transformer with Asymmetrical Winding." Applied Mechanics and Materials 536-537 (April 2014): 1523–26. http://dx.doi.org/10.4028/www.scientific.net/amm.536-537.1523.

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For problems of zero sequence current and negative sequence current of traction transformer in Electrified Railway, a novel balance transformer with asymmetrical windings was presented. By a systematic analysis method based on the magnetic force balance equations, winding connection equations, output-port equations and voltage transfer equations, the current relationships of the primary windings and secondary windings, the balance condition and the short circuit impedances (when the neutral current in the primary side is zero) were deduced, and the electric characteristics of the balance transformer was analyzed. Through the experimental model of balance transformer in simulation platform based on Matlab/Simulink, the electric characteristics of balance transformer and change law of zero sequence current and negative sequence current in different mode were researched. Correctness and feasibility of the theoretical analysis are verified through the simulation experiment.

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50

Im, Seong-Hwan, and Bon-Gwan Gu. "Study of Induction Motor Inter-Turn Fault Part II: Online Model-Based Fault Diagnosis Method." Energies 15, no. 3 (January 28, 2022): 977. http://dx.doi.org/10.3390/en15030977.

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This paper (Part II) is a follow-up paper to our previous work on developing induction motor inter-turn fault (ITF) models (Part I). In this paper, an online ITF diagnosis method of induction motors is proposed by utilizing the negative sequence current as a fault signal based on the fault model of the previous study in part I. The relationships among fault parameters, negative sequence current, and fault copper loss are analyzed with the ITF model. The analyses show that the fault severity index, a function of fault parameters, is directly related to the negative sequence and the copper loss. Therefore, the proposed model-based fault diagnosis method estimates the fault severity index from the negative sequence current and recognizes the ITF. With the estimated fault severity index, the fault copper loss by the ITF, causing thermal degradation, can be calculated. Finally, experiments were performed in various fault conditions to verify the proposed fault diagnosis method.

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