EPE Association: EPE 2020 - DS1g-2: Power Electronics in Transmission and Distribution Systems-2

EPE 2020 - DS1g-2: Power Electronics in Transmission and Distribution Systems-2
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 - DS1g-2: Power Electronics in Transmission and Distribution Systems-2

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   A Combined Model for Optimal Power Flow Applied to MT-HVDC Systems
By TORRES FERNANDO [View]
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Abstract: Multi-terminal HVDC grids based on voltage source converters have been considered a good solution to transmit great power bulks coming from different renewable energy sources. Therefore, it is important to generate useful models that contribute to the operational study of such systems. In particular, it is important to make good use of droop schemes, since these are essential for achieving a correct operation. The main contribution of this article is the development of a combined model based on optimal power flow for radial multi-terminal HVDC grids. This model comprises two sub-models. The first sub-model, which considers the droop scheme associated to the active power loop, is established with the objective of minimizing losses over the DC lines. On the other hand, the second sub-model, which considers the droop scheme associated to the reactive power loop, is established with the objective of minimizing the total apparent power in converter stations and, consequently, minimizing their total losses. The combined model allows selecting the parameters and references associated to both droop schemes. The case study presented shows that the use of the combined model results in a correct grid operation, highlighting the contribution to the needs of the AC grid while maintaining the operational restrictions of the entire system. The simulations are obtained using MATLAB/SIMULINK.

   Future grid stability, a cost comparison of Grid-Forming and Synchronous Condenser based solutions.
By Thibault PREVOST [View]
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Abstract: Grid-Forming inverters have proven to be a key solution for future stability issues in the context of high penetration of power electronics in the grid. As synchronous condensers are presently used to locally solve such issue, this paper compares the costs of two deployment plan of the two solutions to ensure stability of a future realistic scenario in France for 2035. The needs will be based of on the latest work of MIGRATE for the Grid Forming (GFor) solution, and on ENTSOE requirement for inertia for the Synchronous Condenser (SC) scenario. The costs of the two solutions will be based on publicly available data of recent projects.

   Impact of steady-state grid-frequency deviations on the performance of grid-forming converter control strategies
By ANANT NARULA [View]
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Abstract: The aim of this paper is to investigate the impact of steady-state deviations in the grid-frequency on the performance of grid-forming converter control strategies. In particular, the virtual synchronous machine (VSM) control structure has been the focus of study in this paper. Two alternative solutions to address the issue with the conventional VSM structure are suggested, and their impact on the active power response and the power dissipation properties of the converter are compared. For the latter, the ac-side input admittance of the grid-connected converter is derived for the different control structures under consideration. Finally, the dynamic performance of the different control structures is verified through the time-domain simulations.

   Investigation on parallel operation of two MMC-HVDC links in grid forming connected to an existing network
By Hani SAAD [View]
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Abstract: The share of power electronics installations into existing ac power systems is significantly increasing due to the massive penetration of wind power plants and HVDC links. VSC-HVDC link can operate in VF-control (or grid-forming mode) when connected to a weak or islanded network to overcome the PQ-control (or grid-feeding mode) limitation. Up to now, the VF-control represents a challenge due to static and dynamic limits when several HVDC links are in parallel operation. This paper provides a dynamic performance of two HVDC links in grid forming mode connected to an islanded grid. To provide a realistic test case, the islanded grid is based on the Northern France network. AC fault and control instabilities between 2 HVDC links in VF control are analyzed in this work. These set of EMT studies provide an insight on dynamic network behavior when HVDC is operating in VF control.

EPE 2020 - DS1g-2: Power Electronics in Transmission and Distribution Systems-2
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 - DS1g-2: Power Electronics in Transmission and Distribution Systems-2
	[return to parent folder]

	A Combined Model for Optimal Power Flow Applied to MT-HVDC Systems By TORRES FERNANDO	[View] [Download]
Abstract: Multi-terminal HVDC grids based on voltage source converters have been considered a good solution to transmit great power bulks coming from different renewable energy sources. Therefore, it is important to generate useful models that contribute to the operational study of such systems. In particular, it is important to make good use of droop schemes, since these are essential for achieving a correct operation. The main contribution of this article is the development of a combined model based on optimal power flow for radial multi-terminal HVDC grids. This model comprises two sub-models. The first sub-model, which considers the droop scheme associated to the active power loop, is established with the objective of minimizing losses over the DC lines. On the other hand, the second sub-model, which considers the droop scheme associated to the reactive power loop, is established with the objective of minimizing the total apparent power in converter stations and, consequently, minimizing their total losses. The combined model allows selecting the parameters and references associated to both droop schemes. The case study presented shows that the use of the combined model results in a correct grid operation, highlighting the contribution to the needs of the AC grid while maintaining the operational restrictions of the entire system. The simulations are obtained using MATLAB/SIMULINK.

	Future grid stability, a cost comparison of Grid-Forming and Synchronous Condenser based solutions. By Thibault PREVOST	[View] [Download]
Abstract: Grid-Forming inverters have proven to be a key solution for future stability issues in the context of high penetration of power electronics in the grid. As synchronous condensers are presently used to locally solve such issue, this paper compares the costs of two deployment plan of the two solutions to ensure stability of a future realistic scenario in France for 2035. The needs will be based of on the latest work of MIGRATE for the Grid Forming (GFor) solution, and on ENTSOE requirement for inertia for the Synchronous Condenser (SC) scenario. The costs of the two solutions will be based on publicly available data of recent projects.

	Impact of steady-state grid-frequency deviations on the performance of grid-forming converter control strategies By ANANT NARULA	[View] [Download]
Abstract: The aim of this paper is to investigate the impact of steady-state deviations in the grid-frequency on the performance of grid-forming converter control strategies. In particular, the virtual synchronous machine (VSM) control structure has been the focus of study in this paper. Two alternative solutions to address the issue with the conventional VSM structure are suggested, and their impact on the active power response and the power dissipation properties of the converter are compared. For the latter, the ac-side input admittance of the grid-connected converter is derived for the different control structures under consideration. Finally, the dynamic performance of the different control structures is verified through the time-domain simulations.

	Investigation on parallel operation of two MMC-HVDC links in grid forming connected to an existing network By Hani SAAD	[View] [Download]
Abstract: The share of power electronics installations into existing ac power systems is significantly increasing due to the massive penetration of wind power plants and HVDC links. VSC-HVDC link can operate in VF-control (or grid-forming mode) when connected to a weak or islanded network to overcome the PQ-control (or grid-feeding mode) limitation. Up to now, the VF-control represents a challenge due to static and dynamic limits when several HVDC links are in parallel operation. This paper provides a dynamic performance of two HVDC links in grid forming mode connected to an islanded grid. To provide a realistic test case, the islanded grid is based on the Northern France network. AC fault and control instabilities between 2 HVDC links in VF control are analyzed in this work. These set of EMT studies provide an insight on dynamic network behavior when HVDC is operating in VF control.