Closed-Form Earth-Return Impedance Formulas for Overhead and Underground Cables Considering Displacement Currents

カテゴリ: 研究会(論文単位)

論文No: HV20007

グループ名: 【B】電力・エネルギー部門 高電圧研究会

発行日: 2020/01/23

タイトル(英語): Closed-Form Earth-Return Impedance Formulas for Overhead and Underground Cables Considering Displacement Currents

著者名: Liu Zhiqiang (John)(Manitoba Hydro International),Ametani Akihiro(University of Manitoba),Gole Aniruddha(University of Manitoba),De Silva Jeewantha(Manitoba Hydro International)

著者名(英語): Zhiqiang (John) Liu(Manitoba Hydro International),Akihiro Ametani(University of Manitoba),Aniruddha Gole(University of Manitoba),Jeewantha De Silva(Manitoba Hydro International)

キーワード: Earth-return impedance|displacement current|overhead line|underground cable|EMTP|Earth-return impedance|displacement current|overhead line|underground cable|EMTP

要約(日本語): This paper proposes closed-form formulas of earth-return impedances for overhead lines and underground cables, which can deal with high frequency displacement currents. Calculated results by the proposed approximate formulas are compared with those calculated by accurate formulas. It is confirmed that the approximate formula considering the displacement currents for the overhead lines as well as underground cables shows good accuracy in comparison with the accurate formula. The approximate formulas are applied to investigate the influence of the relative earth permittivity on the earth-return impedance. The effect of the displacement currents appears in a high frequency region above 1 MHz in the overhead lines, and in high frequencies higher than 500 kHz in the underground cables. Since the formulas are given in a closed form, those can be easily implemented in existing EMTPs as a numerically stable formula of the earth-return impedances of overhead lines and underground cables to avoid any numerical divergence in frequency domain and instability in time domain.

要約(英語): This paper proposes closed-form formulas of earth-return impedances for overhead lines and underground cables, which can deal with high frequency displacement currents. Calculated results by the proposed approximate formulas are compared with those calculated by accurate formulas. It is confirmed that the approximate formula considering the displacement currents for the overhead lines as well as underground cables shows good accuracy in comparison with the accurate formula. The approximate formulas are applied to investigate the influence of the relative earth permittivity on the earth-return impedance. The effect of the displacement currents appears in a high frequency region above 1 MHz in the overhead lines, and in high frequencies higher than 500 kHz in the underground cables. Since the formulas are given in a closed form, those can be easily implemented in existing EMTPs as a numerically stable formula of the earth-return impedances of overhead lines and underground cables to avoid any numerical divergence in frequency domain and instability in time domain.

原稿種別: 英語

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