Power Distribution Estimation in VSC-based MT-MVDC Distribution System with Droop Control under Steady-State Operation

Pingyang Sun*, Gen Li, Muhammad Khalid, Graham Town, Georgios Konstantinou

*Corresponding author for this work

Research output: Contribution to conferencePaperResearchpeer-review


The challenges of current medium voltage alternating current (MVAC)-led distribution systems result in the development of MV direct current (MVDC) systems. An MVDC system with multiple sources can ensure the uninterrupted power supply of loads in the event of component failure, and multi-terminal MVDC (MT-MVDC) systems can be constituted by linking different MVDC terminals together in various manners.

No detailed power distribution analysis has yet been tailored to VSC-based MVDC distribution systems after different system disturbances, although such analysis for high-voltage DC (HVDC) transmission systems has been studied extensively in the current literature. This paper aims to investigate the detailed steady-state power distribution in VSC-based MT-MVDC distribution systems for ensuring static operation security and benefiting system planning/designing of future MT-MVDC networks. The proposed steady-state power distribution estimation method is critical for the post-contingency operational security of VSC-based MT-MVDC systems.

Similar to the AC distribution networks, different loads can be directly connected into MVDC distribution systems, and tie switches could also be employed to link two or more load terminals together improving power supply reliability in a multiple power supply system after certain power failures. Hence, the power distribution under two possible operation modes of an MVDC distribution system is analysed and estimated in detail. These include i) normal multiple power supply operation after closing tie switches, and ii) operation after converter outage with corresponding tie switch closing.

In addition, droop control is adopted in the MT-MVDC distribution systems, since it is a typical high-level control scheme that shows satisfactory performance that all converters can coordinate to balance the DC voltage, hence operate independently of communications. The detailed droop characteristics of all converters are also considered in the power distribution estimation process.

Simulation results demonstrate the accuracy of the proposed power distribution estimation method for MT-MVDC systems. This paper will be beneficial to the static security assessment of future complex MVDC systems.
Original languageEnglish
Publication date2023
Number of pages14
Publication statusPublished - 2023
EventCIGRE Muscat International Symposium 2023 - Muscat, Oman
Duration: 6 Mar 20238 Mar 2023


ConferenceCIGRE Muscat International Symposium 2023


  • Multi-termal medium-voltage direct current (MT-MVDC) system
  • Voltage source converter (VOC)
  • Power distribution analysis
  • Droop control


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