EPE Association: EPE 2022 - LS6c: AC and DC Grids Applications of Power Converters

EPE 2022 - LS6c: AC and DC Grids Applications of Power Converters
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2022 ECCE Europe - Conference > EPE 2022 - Topic 07: Power Supplies > EPE 2022 - LS6c: AC and DC Grids Applications of Power Converters

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   A Novel Combined Control of Ground Current and DC-pole-to-Ground Voltage in Symmetrical Monopole Modular Multilevel Converters for HVDC Applications
By Pablo BRIFF [View]
[Download]

Abstract: This paper investigates the reduction in converter trips in the symmetrical Modular Multilevel Converter (MMC) by regulating the dc term of the valves' voltages, while allowing the dc pole-to-ground dc voltages to fluctuate within acceptable limits. Moreover, the control method proposed in this work serves two purposes: i) to regulate the pole-to-ground dc voltages of a symmetrical Modular MMC when the voltage of either of the poles at the dc side exceeds a predefined threshold; and ii) to control the ground current within acceptable limits. This results in an extended converter availability by avoiding unnecessary converter trips. The benefits of the proposed method is validated by simulation results for a symmetrical monopole MMC VSC-HVDC configuration.

   Design Concepts for Medium Voltage DC Networks supplying the Future Circular Collider (FCC)
By Manuel COLMENERO MORATALLA [View]
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Abstract: In the frame of the feasibility studies for the construction of the Future Circular Collider (FCC), a newparticle accelerator of 90 km of circumference under design, the use of Medium Voltage DC Grids(MVDC) for distribution has attracted attention considering their potential advantages in terms of transmission losses, power _ow control and energy storage integration.Traditionally, the main concerns of the DC networks have been their reliability and robustness. In thissense, a DC network where the AC/DC and DC/DC converters are based on the MMC (Modular Multi-level Converter) could offer advantages, thanks to the modularity, the easy maintenance, the possibility of integrating distributed energy storage and the redundancy. However, there is little knowledge about how a network for such a large power should be implemented.Accordingly, this work describes the design aspects of a Medium Voltage DC network based on theMMC topology for the FCC, focusing on the speci_cities of non-isolated step-down DC/DC converters and examining how their control should be implemented to power a magnet chain and recover its energy. Additionally, a method to mitigate the impact of DC pole-to-pole and pole-to-ground faults is proposed.

   Fine-grained Dynamics Representation and Stability Analysis for MMC-based Hybrid AC/DC Power Systems
By Chaoyu DONG [View]
[Download]

Abstract: The hybrid AC/DC power system is favored because of its huge energy transmission capacity and excellent steerability. However, the real system is large in scale and the inner dynamics interaction and coupling are intricate, which introduces a series of stability issues for the system operation. To investigate AC/DC interaction dynamics, an MMC-based hybrid power system model is established in the state space. The model considers the detailed dynamics of both AC and DC, and their interaction, thus it can be used for AC/DC interaction study, and offer a more precise stability assessment result than either AC power system model or MMC converter model. After the verification in MATLAB/Simulink, The interaction is studied thoroughly by the proposed model, which clearly identifies the harmonic coupling between MMC and traditional power systems. The small signal stability gaps of different systems are also compared. Case results prove that the reduced-order model can be deployed to assess stability efficiently under specific circumstances. The interaction causes extra harmonics in AC affecting the hybrid system stability.

EPE 2022 - LS6c: AC and DC Grids Applications of Power Converters
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2022 ECCE Europe - Conference > EPE 2022 - Topic 07: Power Supplies > EPE 2022 - LS6c: AC and DC Grids Applications of Power Converters
	[return to parent folder]

	A Novel Combined Control of Ground Current and DC-pole-to-Ground Voltage in Symmetrical Monopole Modular Multilevel Converters for HVDC Applications By Pablo BRIFF	[View] [Download]
Abstract: This paper investigates the reduction in converter trips in the symmetrical Modular Multilevel Converter (MMC) by regulating the dc term of the valves' voltages, while allowing the dc pole-to-ground dc voltages to fluctuate within acceptable limits. Moreover, the control method proposed in this work serves two purposes: i) to regulate the pole-to-ground dc voltages of a symmetrical Modular MMC when the voltage of either of the poles at the dc side exceeds a predefined threshold; and ii) to control the ground current within acceptable limits. This results in an extended converter availability by avoiding unnecessary converter trips. The benefits of the proposed method is validated by simulation results for a symmetrical monopole MMC VSC-HVDC configuration.

	Design Concepts for Medium Voltage DC Networks supplying the Future Circular Collider (FCC) By Manuel COLMENERO MORATALLA	[View] [Download]
Abstract: In the frame of the feasibility studies for the construction of the Future Circular Collider (FCC), a newparticle accelerator of 90 km of circumference under design, the use of Medium Voltage DC Grids(MVDC) for distribution has attracted attention considering their potential advantages in terms of transmission losses, power _ow control and energy storage integration.Traditionally, the main concerns of the DC networks have been their reliability and robustness. In thissense, a DC network where the AC/DC and DC/DC converters are based on the MMC (Modular Multi-level Converter) could offer advantages, thanks to the modularity, the easy maintenance, the possibility of integrating distributed energy storage and the redundancy. However, there is little knowledge about how a network for such a large power should be implemented.Accordingly, this work describes the design aspects of a Medium Voltage DC network based on theMMC topology for the FCC, focusing on the speci_cities of non-isolated step-down DC/DC converters and examining how their control should be implemented to power a magnet chain and recover its energy. Additionally, a method to mitigate the impact of DC pole-to-pole and pole-to-ground faults is proposed.

	Fine-grained Dynamics Representation and Stability Analysis for MMC-based Hybrid AC/DC Power Systems By Chaoyu DONG	[View] [Download]
Abstract: The hybrid AC/DC power system is favored because of its huge energy transmission capacity and excellent steerability. However, the real system is large in scale and the inner dynamics interaction and coupling are intricate, which introduces a series of stability issues for the system operation. To investigate AC/DC interaction dynamics, an MMC-based hybrid power system model is established in the state space. The model considers the detailed dynamics of both AC and DC, and their interaction, thus it can be used for AC/DC interaction study, and offer a more precise stability assessment result than either AC power system model or MMC converter model. After the verification in MATLAB/Simulink, The interaction is studied thoroughly by the proposed model, which clearly identifies the harmonic coupling between MMC and traditional power systems. The small signal stability gaps of different systems are also compared. Case results prove that the reduced-order model can be deployed to assess stability efficiently under specific circumstances. The interaction causes extra harmonics in AC affecting the hybrid system stability.