EPE Association: EPE 2020 - DS1h: HVDC & FACTS

EPE 2020 - DS1h: HVDC & FACTS
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2020 ECCE Europe - Conference > EPE 2020 - Topic 06: Grids, Smart Grids, AC & DC > EPE 2020 - DS1h: HVDC & FACTS

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   AC/DC Dynamic Interactions of MMC-HVDC in Grid-Forming for Wind-Farm Integration in AC Systems
By Rayane MOUROUVIN [View]
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Abstract: This paper studies the dynamic interactions between the AC grids and the DC system. In this work, we focus on MMC-HVDC links interconnecting offshore wind farms and AC systems. The onshore converter is controlled in DC-voltage control mode on the DC side and in grid-forming on the AC side. The authors show the importance of DC-voltage loop design when controlling the MMC in grid-forming mode and its consequences on the MMC internal energy. In the conclusion, some recommendations are made regarding different potential solutions for supporting the DC voltage.

   An IGCT-based Multi-functional MMC System with Commutation and Switching
By CHAOQUN XU [View]
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Abstract: This paper proposes an Integrated gate commutated thyristor (IGCT)-based modular multilevel converter (MMC) system with commutation and switching functions (IGCT-ICS-MMC) to implement its fast DC short-circuit fault recovery scheme. In the event of DC fault, the IGCTs are actively short-circuited to eliminate the rectifier mode of MMC itself. The DC voltage is clamped to zero to prevent the rapid increase of DC fault current, thus reducing the requirement of maximum current interruption capability of the DC switch, which makes the DC solid-state switch could be consisting of IGCT. Therefore, the proposed IGCT-ICS-MMC can be multi-functional, including commutation and switching functions. The IGCT-ICS-MMC showed advantages in fault recovery, economical cost, and power losses, verified by simulation result.

   Impact of DC fault blocking capability on the sizing of the DC-DC Modular Multilevel Converter
By Juan PAEZ [View]
[Download]

Abstract: The capability of DC-DC converters of blocking DC faults is an important issue for the development ofHVDC meshed grids. This paper analyzes the impact on the converter design of including suchcharacteristic for the DC-DC Modular Multilevel Converter. Steady state and transient analysis areproposed and tested, showing how the converter should be oversized to include this feature. From this analysis it is concluded that including the fault blocking capability has an impact on the power losses and the investment in semiconductors but not in the investment on capacitors. The converter presents better indicators for low DC transformation ratios demonstrating the interest of the topology for these applications. However for those ratios, the impact of including fault blocking capability is the highest.

   Transient Voltage Dip Mitigation System Based On Hybrid Modular Multilevel Converters
By MANUEL COLMENERO [View]
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Abstract: This publication presents a novel concept of a mitigation system for transient voltage dips, using a back-to-back HVDC system based on Hybrid Modular Multilevel Converters which could be used for sensitive loads such as critical systems for particle accelerators. The objective of this topology is the reduction of the internal energy storage requirements of the converters compared to conventional Half-Bridge Modular Multilevel Converter topologies. This novel hybrid topology allows to extend the modulation index range beyond one without distortion of the output voltages.

EPE 2020 - DS1h: HVDC & FACTS
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2020 ECCE Europe - Conference > EPE 2020 - Topic 06: Grids, Smart Grids, AC & DC > EPE 2020 - DS1h: HVDC & FACTS
	[return to parent folder]

	AC/DC Dynamic Interactions of MMC-HVDC in Grid-Forming for Wind-Farm Integration in AC Systems By Rayane MOUROUVIN	[View] [Download]
Abstract: This paper studies the dynamic interactions between the AC grids and the DC system. In this work, we focus on MMC-HVDC links interconnecting offshore wind farms and AC systems. The onshore converter is controlled in DC-voltage control mode on the DC side and in grid-forming on the AC side. The authors show the importance of DC-voltage loop design when controlling the MMC in grid-forming mode and its consequences on the MMC internal energy. In the conclusion, some recommendations are made regarding different potential solutions for supporting the DC voltage.

	An IGCT-based Multi-functional MMC System with Commutation and Switching By CHAOQUN XU	[View] [Download]
Abstract: This paper proposes an Integrated gate commutated thyristor (IGCT)-based modular multilevel converter (MMC) system with commutation and switching functions (IGCT-ICS-MMC) to implement its fast DC short-circuit fault recovery scheme. In the event of DC fault, the IGCTs are actively short-circuited to eliminate the rectifier mode of MMC itself. The DC voltage is clamped to zero to prevent the rapid increase of DC fault current, thus reducing the requirement of maximum current interruption capability of the DC switch, which makes the DC solid-state switch could be consisting of IGCT. Therefore, the proposed IGCT-ICS-MMC can be multi-functional, including commutation and switching functions. The IGCT-ICS-MMC showed advantages in fault recovery, economical cost, and power losses, verified by simulation result.

	Impact of DC fault blocking capability on the sizing of the DC-DC Modular Multilevel Converter By Juan PAEZ	[View] [Download]
Abstract: The capability of DC-DC converters of blocking DC faults is an important issue for the development ofHVDC meshed grids. This paper analyzes the impact on the converter design of including suchcharacteristic for the DC-DC Modular Multilevel Converter. Steady state and transient analysis areproposed and tested, showing how the converter should be oversized to include this feature. From this analysis it is concluded that including the fault blocking capability has an impact on the power losses and the investment in semiconductors but not in the investment on capacitors. The converter presents better indicators for low DC transformation ratios demonstrating the interest of the topology for these applications. However for those ratios, the impact of including fault blocking capability is the highest.

	Transient Voltage Dip Mitigation System Based On Hybrid Modular Multilevel Converters By MANUEL COLMENERO	[View] [Download]
Abstract: This publication presents a novel concept of a mitigation system for transient voltage dips, using a back-to-back HVDC system based on Hybrid Modular Multilevel Converters which could be used for sensitive loads such as critical systems for particle accelerators. The objective of this topology is the reduction of the internal energy storage requirements of the converters compared to conventional Half-Bridge Modular Multilevel Converter topologies. This novel hybrid topology allows to extend the modulation index range beyond one without distortion of the output voltages.