A Line Impedance Conditioner for Saturation Mitigation of Zigzag Transformer in Hybrid AC/DC Transmission System Considering Line Unbalances

Liu, Bo; Shi, Xiaojie M.; Li, Yalong; Wang, Fei Fred; Tolbert, Leon M.

doi:10.1109/TPEL.2016.2608864

Title: A Line Impedance Conditioner for Saturation Mitigation of Zigzag Transformer in Hybrid AC/DC Transmission System Considering Line Unbalances

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Abstract

Hybrid ac/dc transmission extends the power transfer capacity of existing long ac lines closer to their thermal limit, by superposing the dc current onto three-phase ac lines through a zigzag transformer. However, this transformer could suffer saturation under unbalanced line impedance conditions. This paper introduces the concept of hybrid line impedance conditioner (HLIC) as a cost-effective approach to compensate for the line unbalance and therefore avoid saturation. The topology and operation principle are presented. The two-level control strategy is described, which enables autonomous adaptive regulation without the need of system-level control. Design and implementation are also analyzed, including dc-link capacitance as one of the key line conditioner components, HLIC installation, and protection under fault conditions. The cost study on this HLIC-based hybrid system is also performed to reveal the benefits of the solution. In conclusion, simulation results and experimental results based on a down-scaled prototype are provided to verify the feasibility of the proposed approach.

Authors:

Liu, Bo ^[1]; Shi, Xiaojie M. ^[1]; Li, Yalong ^[1]; Wang, Fei Fred ^[1];

^[1]

Univ. of Tennessee, Knoxville, TN (United States)

Publication Date:: Tue Sep 13 00:00:00 EDT 2016

Research Org.:: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

Sponsoring Org.:: USDOE; National Science Foundation (NSF)

OSTI Identifier:: 1394583

Grant/Contract Number:: AC05-00OR22725

Resource Type:: Accepted Manuscript

Journal Name:: IEEE Transactions on Power Electronics

Additional Journal Information:: Journal Volume: 32; Journal Issue: 7; Journal ID: ISSN 0885-8993

Publisher:: IEEE

Country of Publication:: United States

Language:: English

Subject:: 30 DIRECT ENERGY CONVERSION; Hybrid ac/dc transmission; hybrid line impedance conditioner (HLIC); saturation; transmission line; unbalance; zigzag transformer

Citation Formats


                    Liu, Bo, Shi, Xiaojie M., Li, Yalong, Wang, Fei Fred, and Tolbert, Leon M. A Line Impedance Conditioner for Saturation Mitigation of Zigzag Transformer in Hybrid AC/DC Transmission System Considering Line Unbalances.  United States: N. p., 2016. 
Web.  doi:10.1109/TPEL.2016.2608864.

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                    Liu, Bo, Shi, Xiaojie M., Li, Yalong, Wang, Fei Fred, & Tolbert, Leon M. A Line Impedance Conditioner for Saturation Mitigation of Zigzag Transformer in Hybrid AC/DC Transmission System Considering Line Unbalances.  United States.  https://doi.org/10.1109/TPEL.2016.2608864

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                    Liu, Bo, Shi, Xiaojie M., Li, Yalong, Wang, Fei Fred, and Tolbert, Leon M. Tue .  
"A Line Impedance Conditioner for Saturation Mitigation of Zigzag Transformer in Hybrid AC/DC Transmission System Considering Line Unbalances".  United States.  https://doi.org/10.1109/TPEL.2016.2608864.  https://www.osti.gov/servlets/purl/1394583.

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@article{osti_1394583,

  title        = {A Line Impedance Conditioner for Saturation Mitigation of Zigzag Transformer in Hybrid AC/DC Transmission System Considering Line Unbalances},

  author       = {Liu, Bo and Shi, Xiaojie M. and Li, Yalong and Wang, Fei Fred and Tolbert, Leon M.},

  abstractNote = {Hybrid ac/dc transmission extends the power transfer capacity of existing long ac lines closer to their thermal limit, by superposing the dc current onto three-phase ac lines through a zigzag transformer. However, this transformer could suffer saturation under unbalanced line impedance conditions. This paper introduces the concept of hybrid line impedance conditioner (HLIC) as a cost-effective approach to compensate for the line unbalance and therefore avoid saturation. The topology and operation principle are presented. The two-level control strategy is described, which enables autonomous adaptive regulation without the need of system-level control. Design and implementation are also analyzed, including dc-link capacitance as one of the key line conditioner components, HLIC installation, and protection under fault conditions. The cost study on this HLIC-based hybrid system is also performed to reveal the benefits of the solution. In conclusion, simulation results and experimental results based on a down-scaled prototype are provided to verify the feasibility of the proposed approach.},

  doi          = {10.1109/TPEL.2016.2608864},

  journal      = {IEEE Transactions on Power Electronics},

  number       = 7,

  volume       = 32,

  place        = {United States},

  year         = {Tue Sep 13 00:00:00 EDT 2016},

  month        = {Tue Sep 13 00:00:00 EDT 2016}

}

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