scholarly journals Validation of EMT Digital Twin Models for Dynamic Voltage Performance Assessment of 66 kV Offshore Transmission Network

2020 ◽  
Vol 11 (1) ◽  
pp. 244
Author(s):  
Saran Ganesh ◽  
Arcadio Perilla ◽  
Jose Rueda Torres ◽  
Peter Palensky ◽  
Mart van der Meijden

The increase in Power Electronic (PE) converters due to the increase in offshore wind energy deployment have given rise to technical challenges (e.g., due to unprecedented fast dynamic phenomena) related to voltage and frequency stability in the power system. In the Offshore Wind Farms (OWFs), the currently available current injection-based voltage control for PE converters are not suitable for voltage control in PE dominated systems due to the absence of continuous voltage control and ineffectiveness during islanding. Moreover, in such power systems, the conventional controllers are not suitable for frequency control due to the absence of dynamic frequency control. The paper presents the Direct Voltage Control (DVC) strategy in a real-time environment to mitigate challenges related to voltage and frequency stability during islanding of OWFs. The control strategy is implemented in the average Electro-magnetic Transient (EMT) model of Type-4 Wind Generator (WG) in RSCAD® Version 5.011.1. It is compared with the benchmark model of the control strategy in DIgSILENT PowerFactoryTM 2019 SP2 (×64) in EMT platform. The comparison based on short-term voltage stability and reactive current injection reveals that both the models provide similar results, confirming the validation of the RSCAD model. Moreover, the detailed representation of the converters in the RSCAD model provides a better depiction of the real-world operation.

Energies ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3879 ◽  
Author(s):  
Ali Bidadfar ◽  
Oscar Saborío-Romano ◽  
Vladislav Akhmatov ◽  
Nicolaos A. Cutululis ◽  
Poul E. Sørensen

Offshore high-voltage DC (HVDC) grids are developing as a technically reliable and economical solution to transfer more offshore wind power to onshore power systems. It is also foreseen that the offshore HVDC grids pave the way for offshore wind participation in power systems’ balancing process through frequency support. The primary frequency control mechanism in an HVDC grid can be either centralized using communication links between HVDC terminals or decentralized by the simultaneous use of DC voltage and frequency droop controls. This paper investigates the impact of both types of primary frequency control of offshore HVDC grids on onshore power system dynamics. Parametric presentation of power systems’ electro-mechanical dynamics and HVDC controls is developed to analytically prove that the primary frequency control can improve the damping of interarea modes of onshore power systems. The key findings of the paper include showing that the simultaneous use of frequency and DC voltage droop controls on onshore converters results in an autonomous share of damping torque between onshore power systems even without any participation of offshore wind farms in the frequency control. It is also found that the resulting damping from the frequency control of offshore HVDC is not always reliable as it can be nullified by the power limits of HVDC converters or wind farms. Therefore, using power oscillation damping control in parallel with frequency control is suggested. The analytical findings are verified by simulations on a three-terminal offshore HVDC grid.


Energies ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1914 ◽  
Author(s):  
Roland Ryndzionek ◽  
Łukasz Sienkiewicz

This paper presents an overview of the DC link development and evolution dedicated to HVDC structure for connecting offshore wind power plants to onshore power systems. The growing demand for the green energy has forced investors in power industry to look for resources further out at sea. Hence, the development of power electronics and industrial engineering has enabled offshore wind farms to be situated further from the shore and in deeper waters. However, their development will require, among other technologies, DC-DC conversion systems. The advantages of HVDC over HVAC technology in relation to transmission distance are given. The different HVDC configurations and topologies of HVDC converters are elucidated. In this context, the HVDC grids are a promising alternative for the expansion of the existing AC grid.


2003 ◽  
Vol 27 (4) ◽  
pp. 239-256 ◽  
Author(s):  
A G Dutton

Hydrogen is a leading contender to become an alternative to fossil fuel for transport and for heat and power systems. The potential for the integration of water electrolysis systems in land based and offshore wind farms is explored and compared with the conventional alternative – steam reforming of methane. Depending on the specific production technology, hydrogen can displace fossil fuels and so reduce or completely remove the emission of carbon dioxide and other pollutants. This paper examines the principal technologies for producing hydrogen and shows how the eventual choice is likely to depend as much on political and legislative factors as on economic criteria.


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