3D Full-Maxwell Simulations of Very Fast Transients in GIS

Smajić, Jasmin; Holaus, Walter; Kostovic, Jadran; Riechert, Uwe

doi:10.1109/tmag.2010.2090653

Cited by 45 publications

(9 citation statements)

References 2 publications

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“…Ten pieces of rings are employed with a different impedance ratio to be compared, and it appears that the ring cluster achieves its best damping performance at . Since the charging circuit is ideal and very simple with no specific GIS components but only a bus duct, and the purpose is merely to show that the trends are consistent with the theoretical analysis, there is no need to conduct the 3-D Full-Maxwell simulation as shown in [13]. Thus, the bus duct is simply modeled with a transmission line and the ring cluster is modeled with lumped elements discussed before.…”

Section: B Simulationmentioning

confidence: 99%

“…Derived from (5) and (6), the largest db loss at a certain frequency caused by a ring cluster which holds a length of can be approximately calculated (13) where is total length of the GIS busbar, and characterizes the natural frequency of the circuit, which is always the major component of VFT and holds an order of megahertz. Let us take 0.1 db as the boundary between the no-damping and damping band, then the low cutoff frequency of the damping band can be obtained (14) Since the length of the ring cluster can never exceed the total length , and is unlikely to exceed , thus even under the most extreme condition is certainly to be above 400 Hz.…”

Section: Influence On Power Frequencymentioning

confidence: 99%

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Design Optimization of Ferrite Rings for VFTO Mitigation

Guan

Liu

et al. 2024

IEEE Trans. Power Delivery

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very-fast transient overvoltage (VFTO)-related problems are raising growing concerns in China with the development of ultra-high voltage. The practice of fitting ferrite rings on gas-insulated switchgear busbars for VFTO mitigation has long been proposed but few investigations on its design optimization were conducted. Based on theoretical analysis of the simplified model, the optimal damping condition of ferrite rings is proposed, which is conducive to the type selection. The number of rings to be employed to ensure visible suppressing effects is given through simulations and the influence of the saturation is discussed. Impact on the power frequency is analyzed to be negligible. Finally, comparisons are made between the theoretical conclusions and existing experiment results, which approve the optimal damping condition and agree with the number of rings to be employed.

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Section: B Simulationmentioning

confidence: 99%

Section: Influence On Power Frequencymentioning

confidence: 99%

Design Optimization of Ferrite Rings for VFTO Mitigation

Guan

Liu

et al. 2024

IEEE Trans. Power Delivery

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“…The method of performing VFTO single-spark simulations with full-Maxwell (e.g. FEM-based) approach is reported in [24,25].…”

Section: Disconnector Modelmentioning

confidence: 99%

Multi-spark modeling of very fast transient overvoltages for the purposes of developing HV and UHV gas-insulated switchgear and of conducting insulation co-ordination studies

Szewczyk¹

2017

Bulletin of the Polish Academy of Sciences Technical Sciences

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Abstract. Very fast transient overvoltages (VFTO) originate from steep voltage breakdowns in SF 6 gas that are inherent to operation of any switching device of the gas-insulated switchgear (GIS) type. For power stations with voltage ratings exceeding 500 kV, the ratio between equipment rated-and withstand-voltage levels becomes relatively low, which causes the VFTO peak values to reach the component's insulation withstand-voltage levels, thus becoming a design factor for high-and ultra-high voltage GIS. While well-established approach to VFTO analyses involves only single VFTO events (the so-called single-spark approach), there is often the need to analyze the entire VFTO generation process, for which the multi-spark approach to VFTO modeling is to be employed. The multi-spark approach allows one to evaluate the VFTO impact on the GIS disconnector design along with the impact of the VFTO on selection and dimensioning of the VFTO damping solutions. As the multi-spark approach to VFTO modeling is now being increasingly used in UHV GIS developments as well as for the insulation co-ordination studies of power stations, the present paper is motivated by the need to report on the VFTO multi-spark modeling approach and to lay a common ground for development works that are supported extensively with VFTO simulations. The paper presents physical assumptions and modeling concepts that are in use in such modeling works. Development of the multi-spark GIS disconnector model for VFTO simulations is presented, followed by an overview of examples of the model application for the GIS development works and for insulation co-ordination studies.Key words: very fast transient overvoltages (VFTO), gas-insulated switchgear (GIS), disconnector switch (DS), modeling, simulations, transients, switching, mitigation, breakdown voltage (BDV) characteristics. Multi-spark modeling of very fast transient overvoltages for the purposes of developing HV and UHV gas-insulated switchgearand of conducting insulation co-ordination studies To explore the VFTO associated with the operation of the UHV GIS disconnectors, the State Grid Corporation of China (SGCC) has recently established two full-scale test set-ups at the 1100 kV station in Wuhan (China), and conducted measuring campaigns with the total number of disconnector operations of approximately 2000 [8]. Several papers have been published based on this work, addressing different aspects of VFTO measurements and simulations. As an example, in [9] the impact of the disconnectors moving contact speed on the variety of VFTO parameters is analyzed.Also in the previous works conducted by ABB, the VFTO have been investigated to support design work of the 1100 kV disconnector [10,11] and to analyze the impact of the VFTO on selection of the VFTO damping solutions [6]. These works utilized the so-called multi-spark approach [4,12] for modeling the entire process of disconnector operation and to analyze distributions of the VFTO, along with other parameters, such as trapped charge voltage distributions, ...

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“…Despite the fact that numerical methods such as finite differences and finite elements are commonly used to solve the TE-eddy current problems and also to simulate the VFT phenomena within a short segment of GIS [2], a simple but efficient circuit model method may be preferred in the simulation of VFT mitigation by magnetic rings. Because the number of rings (several tens), the saturation effect and the whole size of GIS have considerably increased the complexity and time-cost of the numerical calculation.…”

Section: Introductionmentioning

confidence: 99%

A Circuit Model of Transverse Electric Eddy-Current Problems in Magnetic Rings

Liu

Guan

2015

IEEE Trans. Magn.

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A circuit model consisting of inductance-resistance ladder network to solve the transverse electric eddy current problems was proposed. The general idea is to divide the region to be solved into a number of eddy shells, which are modeled by a series of coils magnetically coupled with each other. Detailed discussions of the model were made under two special cases where analytical solutions are available. First, it was proved in theory that the limit form of the recursive formula of the circuit model is identical with the Maxwell equations. Next, numerical accuracy of the model was evaluated by making comparison between the circuit solutions and the analytical solutions. It turns out that when the width of each shell is less than the skin depth, the results match the analytical solutions quite well. The proposed circuit model could find its application in the simulation of VFTO (Very Fast Transient Overvoltage) mitigation by magnetic rings, where analytical solutions do not exist and other commonly-used numerical methods cost too much calculation amount.

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3D Full-Maxwell Simulations of Very Fast Transients in GIS

Cited by 45 publications

References 2 publications

Design Optimization of Ferrite Rings for VFTO Mitigation

Design Optimization of Ferrite Rings for VFTO Mitigation

Multi-spark modeling of very fast transient overvoltages for the purposes of developing HV and UHV gas-insulated switchgear and of conducting insulation co-ordination studies

A Circuit Model of Transverse Electric Eddy-Current Problems in Magnetic Rings

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