Impact of stray capacitance on HVDC harmonics

Larsen, E.V.; Sublich, M.; Kapoor, Sanjiv

doi:10.1109/61.19256

Cited by 25 publications

(2 citation statements)

References 2 publications

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“…The surge capacitance will force a low termination impedance [4], where the typical value was found to be from a few to tens of nF [30][31][32]. Except the capacitive component terminal, at higher frequency, the power station should be expected to present stray capacitances towards ground [33,34], which will produce a lower input impedance compared to the characteristic of the DC line in the high frequency range as well. For isolation switches and circuit breakers stray capacitances around 0.1 nF have been reported [18].…”

Section: Terminal Boundarymentioning

confidence: 99%

On-Site Experimental Analysis for Impact of Wideband Terminal Model to Transient Overvoltage Based on a Full-Scale 200kV MMC-HVDC Converter Station

Cozza

Song

et al. 2023

Preprint

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This paper investigates the impact of power converter station modeling to high frequency overvoltage based on the on-site experimental test of a fully operational 200 kV MMC-HVDC converter station. Artificial short-circuit faults were generated in the system with hybrid DC circuit breakers along coaxial cables by means of an unmanned aerial vehicle for the first time. Fault transients recorded during the tests are found not to comply with the typical framework where power stations are assumed to present a high impedance, or at least dominated by the reactor inductance. This discrepancy is proven to be caused by parasitic elements at the terminals of the converter station, resulting in a spurious low-frequency resonance dominating fault transients. A wideband converter station model is proposed and validated by the test data. The simulation results show that the proposed wideband model should be adopted avoiding the risk of huge resonance bias in short line distance. When fault distance is 10 km away, converter station model will converge to standard AVM, while the high impedance or reactor model is no longer valid. The experimental data provide a benchmark to validate the converter station model for transient overvoltage or electromagnetic interference under the fault condition.

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Section: Terminal Boundarymentioning

confidence: 99%

On-Site Experimental Analysis for Impact of Wideband Terminal Model to Transient Overvoltage Based on a Full-Scale 200kV MMC-HVDC Converter Station

Cozza

Song

et al. 2023

Preprint

View full text Add to dashboard Cite

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“…Further potential sources of location errors can be expected from the non-ideal high-frequency behavior of devices as reactors and circuit breakers. Turn-to-turn stray capacitances are known to exist in reactors, as well as toward surrounding systems, in particular grounded conductors [48]- [51]. Equivalent models introduce a leakage capacitance in parallel to a device, and shunt capacitances connecting each end to the ground.…”

Section: Stray Capacitancesmentioning

confidence: 99%

Fault-Location Accuracy of Natural Frequencies Using Incomplete HVDC Station Models

Cozza

2023

IEEE Trans. Power Delivery

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This paper investigates how the accuracy of fault location estimated from a transmission line's natural frequencies is affected by imperfect modeling of HVDC power-converter stations. These systems include a large number of devices each with specific frequency-dependent characteristics, as filters, reactors and surge protection systems. While it is well-known that location errors may ensue from inaccurate termination models, it is not clear to what extent location accuracy is affected when neglecting one or more of these devices. Results show significant differences depending on the kind of transmission line and the reactor inductance. Including reactors is found not to completely avoid errors, proving the need to take into account the reactive behavior of the converter, which strongly varies according to the HVDC technology. A notable source of errors is level repulsion between station and line resonances, a phenomenon observed when the converter station presents self resonances, e.g., due to DC filters and stray capacitances in reactors. Significant loss of sensitivity to the fault position is found in these cases, impairing fault-location resolution. The first, or dominant, natural frequency of the line is more strongly affected by all these phenomena, suggesting that the standard choice of using the dominant resonance may not be an optimal strategy. Higher-order resonances are instead found to be more robust against inaccurate converter models, and appear to be more suitable for accurate fault location in case of uncertainties about the converter model.

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