Abstract
The application of the direct current (DC) transmission is increasing through the interconnection between grids or the renewable energy resource integration. Various types of DC transmission topology are researched, and the hybrid multi-terminal high voltage DC (HVDC), called the “MTDC”, is one of the research subjects. The hybrid multi-terminal HVDC is the MTDC system that is composed with the Line Commutated Converter (LCC) and Voltage Source Converter (VSC). Most hybrid MTDC research has been focused on the connection of the renewable energy generation sources, especially offshore wind farms. However, the DC grid built with a hybrid MTDC was recently proposed due to the development of the converter technology. Therefore, the DC grid is expected to be able to substitute some parts of the transmission grid instead of the alternating current (AC) system, and the operation strategies of the DC grid are still being researched. The DC grid has the advantage of being able to control the power flow, which can even improve the stability of the connected AC system. The dynamic model is required to analyze the improvement of the AC system by the operation strategy of the hybrid MTDC, however, there is no generic model for the system. In this paper, an operation strategy of the hybrid MTDC is proposed to improve the stability of the AC power system by increasing the utilization of parallel AC transmission lines under the contingency condition. Furthermore, studies on the modeling method for a hybrid MTDC analysis were performed. The proposed modeling method and operation strategy were verified in simulations for which a modified IEEE 39 bus test system was used. The improvement of transient stability by the proposed hybrid MTDC system was shown in the simulation results.
Original language | English |
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Article number | 2042 |
Journal | Energies |
Volume | 12 |
Issue number | 11 |
DOIs | |
Publication status | Published - 2019 |
Bibliographical note
Funding Information:A generic LCC MTDC model and a CRPS model were used in the approximate hybrid MTDC model; the MTDC model controlled the active power, and the reactive power was controlled by the model; the MTDC model controlled the active power, and the reactive power was controlled by the CRPS model. The control of the hybrid MTDC model, in terms of the active power and the reactive CRPS model. The control of the hybrid MTDC model, in terms of the active power and the reactive power, was verified via simulations. The proposed modeling method is for a power system analysis, power, was verified via simulations. The proposed modeling method is for a power system analysis, and the focus of the model is the independent control of the active power and the reactive power. and the focus of the model is the independent control of the active power and the reactive power. The operation strategy for the hybrid MTDC is proposed and evaluated, according to a dynamic The operation strategy for the hybrid MTDC is proposed and evaluated, according to a dynamic simulation. The model was applied to the test system, and the operation strategy was evaluated. A simulation. The model was applied to the test system, and the operation strategy was evaluated. A multi terminal DC grid improved the AC system utilization, and the proposed operation strategy multi terminal DC grid improved the AC system utilization, and the proposed operation strategy improved the transient stability of the power system. To add, the overload was considered and the improved the transient stability of the power system. To add, the overload was considered and the effect was verified. The stability improvement by the operation strategy is verified in the actual system effect was verified. The stability improvement by the operation strategy is verified in the actual data as well. The hybrid MTDC system is applied in the Korean power system and the transient system data as well. The hybrid MTDC system is applied in the Korean power system and the stability analysis was conducted. The hybrid DC system can reduce the generator outage in the severe transient stability analysis was conducted. The hybrid DC system can reduce the generator outage in contingency by the operation strategy proposed. the severe contingency by the operation strategy proposed. Author Contributions: The hybrid MTDC system modeling method and the operation strategy were proposed Author Contributions: The hybrid MTDC system modeling method and the operation strategy were proposed by S.H., S.S., M.Y., and G.J. The experiment results were collected and analyzed by S.H., S.S., M.Y., and G.J. by S.H., S.S., M.Y., and G.J. The experiment results were collected and analyzed by S.H., S.S., M.Y., and G.J. Funding: This research was supported by Korea Electric Power Corporation. (R18XA06-62) and under the Funding: This research was supported by Korea Electric Power Corporation. (R18XA06-62) and under the (Nfora. m20e1w7Kor1kAo4fAt3h0e1i3n5t7e9r)n.ational cooperation program managed by the National Research Foundation of Korea. Conflicts of Interest: The authors declare no conflict of interest.
Publisher Copyright:
© 2019 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license
Keywords
- HVDC transmission
- Hybrid multi-terminal HVDC
- LCC
- MTDC
- Power system analysis
- VSC
ASJC Scopus subject areas
- Renewable Energy, Sustainability and the Environment
- Energy Engineering and Power Technology
- Energy (miscellaneous)
- Control and Optimization
- Electrical and Electronic Engineering