Life consumption of a MMC-STATCOM supporting wind power plants: Impact of the modulation strategies

Sousa, Renata Oliveira de; Farias, João Victor Matos; Cupertino, Allan Fagner; Pereira, Heverton A.

doi:10.1016/j.microrel.2018.06.111

Cited by 7 publications

(5 citation statements)

References 10 publications

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“…Metallised polypropylene film capacitors (MPPFCs) are ubiquitous in power electronics, such as static synchronous compensators (STATCOM), motor drives, and modular multilevel converters, due to their high breakdown strengths, good dielectric stability, and low dissipation factors [1][2][3]. In power electronics, the PP film in the capacitor must endure electrical and thermal stresses that can rise above 200 V/μm and around 150°C [4].…”

Section: Introductionmentioning

confidence: 99%

Revisiting the thermal ageing on the metallised polypropylene film capacitor: from device to dielectric film

Wang

et al. 2022

High Voltage

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Metallised polypropylene film capacitors (MPPFCs) are widely used in power electronics and are generally degraded by elevated temperatures. This work aims to determine the relationships between the structural changes of MPPFC and the microstructural variations of the PP film during the thermal ageing of MPPFC at 100°C for 38 days. The capacitance of MPPFC has a slight decrease during thermal ageing. However, the breakdown voltage of the MPPFC decreases by 39.4% by the ageing. The partial discharge (PD) number of MPPFC increases linearly with ageing time. The tear-down analysis of the MPPFC reveals that the molecular structure of the PP film has not been altered but has led to molecular chain scission and the generation of some polar fragments/groups. Meanwhile, the relative permittivity of the PP films rises as the ageing time increases. Moreover, thermal ageing causes the conversion of aluminum to alumina in the metallised electrode, which is hydrophilic for polar groups and leads to an adhesion effect between the metallised electrodes and the PP film. Contact angle measurements prove that the surface hydrophilicity of the PP sample increased after thermal ageing. Therefore, the PD/breakdown voltage in the MPPFC increases/decreases due to the uneven adhesion of the metallised PP film. | INTRODUCTIONMetallised polypropylene film capacitors (MPPFCs) are ubiquitous in power electronics, such as static synchronous compensators (STATCOM), motor drives, and modular multilevel converters, due to their high breakdown strengths, good dielectric stability, and low dissipation factors [1][2][3]. In power electronics, the PP film in the capacitor must endure electrical and thermal stresses that can rise above 200 V/μm and around 150°C [4]. In addition, capacitors with a proper performance at elevated temperatures facilitate practicable thermal management in application scenarios where the volume and weight are limited, typically in electric vehicles [5,6]. However, elevated temperatures may significantly reduce the life expectancy of the capacitors [7].Thermal ageing is considered as one of the most critical factors, which leads to severe degradation of the PP film and consequent capacitor failure [8]. It has been recognised that the PP films have a very low dielectric loss (~10 −4 ) at temperatures up to 85°C. Once the temperature exceeds 85°C, electron conduction starts to contribute to a significant increase in dielectric loss [9,10]. Qi et al. [11] discovered that the hotspot This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

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Section: Introductionmentioning

confidence: 99%

Revisiting the thermal ageing on the metallised polypropylene film capacitor: from device to dielectric film

Wang

et al. 2022

High Voltage

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“…For NLC, the switching events occur only when it is necessary. 40 For this reason, the effective output frequency of NLC is variable. Nevertheless, the condition of f s > πNf g must be fulfilled to avoid high total harmonic distortion.…”

Section: Switching and Sampling Frequenciesmentioning

confidence: 99%

“…For NLC, the switching events occur only when it is necessary 40 . For this reason, the effective output frequency of NLC is variable.…”

Section: Mmc‐statcommentioning

confidence: 99%

Control tuning methodology for modular multilevel converter‐based STATCOM

Sousa,

Cupertino,

Pinto

et al. 2023

Circuit Theory & Apps

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SummaryThe application of modular multilevel converters (MMC) in medium voltage static synchronous compensators (STATCOMs) has been investigated in recent years. A huge challenge for MMC‐STATCOM is to compute the gain of the controllers. Therefore, the contribution of this paper is the proposal of a control tuning methodology for MMC‐STATCOM. For this purpose, the control and tuning strategies are presented. Since MMC‐STATCOM can employ different modulation strategies, two distinct modulation strategies are considered: nearest‐level control, with variable switching frequency; and phase‐shifted carrier pulse‐width modulation, with fixed switching frequency. Moreover, the proposal was validated through simulation and an experimental platform. The results indicate that the power response follows the reference, besides supplying the internal losses of the converter. The 10% ripple tolerance of the submodule voltages is respected in steady state for both modulation strategies. Moreover, the 5% total demand distortion (TDD) limit recommended by the Institute of Electrical and Electronics Engineers (IEEE) standard is attended. These results demonstrate the effectiveness of the controls employed.

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“…The main influencing factors include wind speed, air temperature and switching frequency. The output power of MMC for wind power transmission greatly changes with the wind speed fluctuation [4], [5]. It will affect the junction temperature swings of power devices, and eventually influence the reliability of MMC.…”

Section: Introductionmentioning

confidence: 99%

Operational Reliability Model of Hybrid MMC Considering Multiple Time Scales and Multi-state Submodule

Feng

Dai

et al. 2021

Journal of Modern Power Systems and Clean Energy

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Environmental and electrical factors such as wind speed, air temperature and switching frequency have significant influences on the operational reliability of hybrid modular multilevel converter (MMC), which is commonly used for the wind power transmission. However, the existing reliability model of hybrid MMC based on statistics cannot accurately reflect the impact of these factors. In this paper, a new operational reliability model of hybrid MMC is presented. The reliability index of the hybrid MMC is coupled with its operation characteristics by calculating multi-term thermal cycling. In addition, an operation strategy of hybrid MMC is proposed to improve its reliability. The multi-state submodule (SM) is developed, which is capable of bypassing specific faulty power modules instead of the whole SM. Case studies show that the proposed operational reliability model could describe the impact of environmental and electrical factors. Also, the proposed operation strategy can improve the reliability of hybrid MMC by extending the operation time of SMs.

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Life consumption of a MMC-STATCOM supporting wind power plants: Impact of the modulation strategies

Cited by 7 publications

References 10 publications

Revisiting the thermal ageing on the metallised polypropylene film capacitor: from device to dielectric film

Revisiting the thermal ageing on the metallised polypropylene film capacitor: from device to dielectric film

Control tuning methodology for modular multilevel converter‐based STATCOM

Operational Reliability Model of Hybrid MMC Considering Multiple Time Scales and Multi-state Submodule

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