In the de-icing process of double-circuit direct current(DC)transmission lines on the same tower,an operational condition exists in which one circuit is de-energised and utilised as part of the de-icing current path,s...In the de-icing process of double-circuit direct current(DC)transmission lines on the same tower,an operational condition exists in which one circuit is de-energised and utilised as part of the de-icing current path,specifically designed for grounding line de-icing purposes.Accurate calculation of the floating potential of the out-of-service line is crucial for the design of de-icing devices.This study employs the upstream finite element method combined with a potential prediction correction approach to determine the floating potential of de-energised conductors.A field-circuit model is proposed for calculating conductor floating potentials under single-circuit outage conditions in double-circuit DC transmission lines.The charge dissipation process through grounding resistors with varying values is also analysed.In a�500 kV case study,the relative errors between the circuit model and electric field model calculations for the positive and negative conductor floating potentials are merely 3.66%and 0.89%,respectively,verifying the validity of the circuit model.The equivalent resistance of ion flow fields reaches magnitudes of 106Ω,significantly exceeding the intrinsic resistance of the conductors.When using voltage-limiting resistors,conductor voltages decrease significantly with a 0.5-MΩresistor,and the calculated floating potentials become 8.702 kV and−5.849 kV,reflecting reductions of 84.8%and 88.4%,respectively.This research demonstrates that the proposed method provides an effective solution for floating potential calculation during single-circuit outages in double-circuit DC lines.The analysis of charge dissipation through voltage-limiting resistors offers technical support for designing DC de-icing devices.展开更多
基金supported by the Science and Technology Project of State Grid Corporation of China(5200-202455431A-3-6-RW).
文摘In the de-icing process of double-circuit direct current(DC)transmission lines on the same tower,an operational condition exists in which one circuit is de-energised and utilised as part of the de-icing current path,specifically designed for grounding line de-icing purposes.Accurate calculation of the floating potential of the out-of-service line is crucial for the design of de-icing devices.This study employs the upstream finite element method combined with a potential prediction correction approach to determine the floating potential of de-energised conductors.A field-circuit model is proposed for calculating conductor floating potentials under single-circuit outage conditions in double-circuit DC transmission lines.The charge dissipation process through grounding resistors with varying values is also analysed.In a�500 kV case study,the relative errors between the circuit model and electric field model calculations for the positive and negative conductor floating potentials are merely 3.66%and 0.89%,respectively,verifying the validity of the circuit model.The equivalent resistance of ion flow fields reaches magnitudes of 106Ω,significantly exceeding the intrinsic resistance of the conductors.When using voltage-limiting resistors,conductor voltages decrease significantly with a 0.5-MΩresistor,and the calculated floating potentials become 8.702 kV and−5.849 kV,reflecting reductions of 84.8%and 88.4%,respectively.This research demonstrates that the proposed method provides an effective solution for floating potential calculation during single-circuit outages in double-circuit DC lines.The analysis of charge dissipation through voltage-limiting resistors offers technical support for designing DC de-icing devices.
