Search

KR-20260063981-A - SYSTEM AND METHOD FOR ADAPTIVE VOLTAGE AND POWER CONTROL OF MULTIPLE TERMINALS IN AC AND DC HYBRID DISTRIBUTION SYSTEM

KR20260063981AKR 20260063981 AKR20260063981 AKR 20260063981AKR-20260063981-A

Abstract

The present invention provides an adaptive voltage and power control system and method for the interconnection of multiple terminals in an AC and DC hybrid distribution system. An adaptive voltage and power control system for the connection of multiple terminals in an AC and DC hybrid distribution system according to one embodiment of the present invention comprises: a distribution system information acquisition unit that acquires information on a plurality of AC and DC distribution systems connected to each other at a plurality of terminals; a power flow analysis unit that performs power flow analysis of the AC and DC distribution systems based on the information on the AC and DC distribution systems; an additional capacity calculation unit that calculates the real-time additional capacity of distributed power sources in the AC distribution system based on the power flow analysis of the AC and DC distribution systems; a plurality of voltage source AC/DC converters that transmit surplus power generation of distributed power sources connected to the DC distribution system to the AC distribution system based on the additional capacity of distributed power sources in the AC distribution system; and a central energy management system (EMS) that outputs power control commands to each voltage source AC/DC converter to control the amount of flexible power to be transmitted from each voltage source AC/DC converter to each AC distribution system. The adaptive voltage and power control system and method for interconnecting multiple terminals in an AC and DC hybrid distribution system according to the present invention can improve voltage stability and capacity of a DC distribution system.

Inventors

  • 정일엽
  • 트린피하이
  • 권녕학

Assignees

  • 국민대학교산학협력단

Dates

Publication Date
20260507
Application Date
20241031

Claims (18)

  1. A distribution system information acquisition unit that acquires information on multiple alternating current (AC) and multiple direct current (DC) distribution systems interconnected at multiple terminals; A power flow analysis unit that performs power flow analysis of the AC and DC distribution systems based on information regarding the AC and DC distribution systems; An additional capacity calculation unit that calculates the real-time additional capacity of distributed power sources in the AC distribution system based on the power flow analysis of the AC and DC distribution systems; A plurality of voltage source AC/DC converters that transmit surplus power generation of distributed power connected to the DC distribution system to the AC distribution system based on the additional capacity of distributed power to be accommodated in the AC distribution system; and An adaptive voltage and power control system for interconnecting multiple terminals in an AC and DC hybrid distribution system, comprising: a central energy management system (EMS) that outputs power control commands to each of the voltage source AC/DC converters to control the amount of flexible power to be transmitted from each of the voltage source AC/DC converters to each of the AC distribution system.
  2. In claim 1, An adaptive interconnection voltage and power control system of multiple terminals in an AC and DC hybrid distribution system, wherein information regarding the above AC and DC distribution system includes at least one bus voltage, at least one line current, and at least one of active power and reactive power of at least one distributed energy resource.
  3. In claim 1, An adaptive interconnected voltage and power control system of multiple terminals in an AC and DC hybrid distribution system, wherein each of the above voltage source AC/DC converters is configured to adjust the amount of flexible power to be transmitted to each of the above AC distribution systems according to a preset droop gain.
  4. In claim 3, An adaptive interconnected voltage and power control system for multiple terminals in an AC and DC hybrid distribution system, characterized in that the above power control command is a signal for adjusting the droop gain of each of the above voltage source AC/DC converters.
  5. In claim 4, An adaptive interconnected voltage and power control system for multiple terminals in an AC and DC hybrid distribution system, characterized in that the above droop gain adjustment adjusts the amount of active power exchanged between the AC distribution system and the DC distribution system according to the rise or fall of the voltage of the DC distribution system.
  6. In claim 5, The bus terminal voltage change amount calculation unit for calculating the voltage change amount of a plurality of bus terminals connected to each of the above-mentioned voltage source AC/DC converters is further included. The rise or fall in voltage of the above DC distribution system reflects the voltage change amount of the above plurality of bus terminals, and An adaptive interconnected voltage and power control system for multiple terminals in an AC and DC hybrid power distribution system, characterized in that the voltage change amount of each of the above-mentioned bus terminals is calculated by multiplying the power applied to the bus terminals by the voltage sensitivity factor (VSF) of each of the above-mentioned bus terminals.
  7. In claim 4, The above droop gain is determined by the ratio of the voltage change amount of a plurality of buses of the DC distribution system connected to the voltage source AC/DC converter to the amount of active power exchanged between the AC distribution system and the DC distribution system, and An adaptive interconnection voltage and power control system for multiple terminals in an AC and DC hybrid distribution system, characterized in that the calculation of the above droop gain is repeated at time intervals predefined by the above central energy management system (EMS).
  8. In claim 7, An adaptive interconnected voltage and power control system for multiple terminals in an AC and DC hybrid distribution system, characterized in that the power flow analysis unit performs power flow analysis of the AC and DC distribution system by considering the operation of the voltage source AC/DC converter with the droop gain applied, which is periodically updated.
  9. In claim 6, An adaptive interconnected voltage and power control system for multiple terminals in an AC and DC hybrid distribution system, characterized in that the above voltage sensitivity index (VSF) is the ratio of the voltage change amount at the second bus terminal to the power change amount at the first bus terminal.
  10. Information acquisition step of acquiring information on multiple alternating current (AC) and multiple direct current (DC) distribution systems interconnected at multiple terminals by a distribution system information acquisition unit; A power flow analysis step in which a power flow analysis unit performs a power flow analysis of the AC and DC distribution systems based on information regarding the AC and DC distribution systems; An additional capacity calculation step for calculating the real-time additional capacity of distributed power sources of the AC distribution system based on the power flow analysis of the AC and DC distribution systems by the additional capacity calculation unit; and A flexible power transmission step of transmitting surplus power generation of a distributed power source connected to the DC distribution system to the AC distribution system based on the additional capacity of the distributed power source to be accommodated in the AC distribution system by means of a voltage source AC/DC converter; wherein Adaptive voltage and power control method for multiple terminals in an AC and DC hybrid distribution system, wherein the above voltage source AC/DC converter is placed at each terminal and receives power control commands from a central energy management system (EMS) to control the amount of flexible power to be transmitted to each of the above AC distribution systems.
  11. In claim 10, A method for controlling adaptive interconnection voltage and power of multiple terminals in an AC and DC hybrid distribution system, wherein information regarding the above AC and DC distribution system includes at least one of a busbar voltage, at least one line current, and at least one active power and reactive power of at least one distributed energy resource.
  12. In claim 10, Adaptive interconnected voltage and power control method for multiple terminals in an AC and DC hybrid power distribution system, wherein the above voltage source AC/DC converter is configured to adjust the amount of flexible power to be transmitted to each of the above AC power distribution systems according to a preset droop gain.
  13. In claim 12, Adaptive interconnection voltage and power control method for multiple terminals in an AC and DC hybrid distribution system, characterized in that the above power control command is a signal for adjusting the droop gain of the above voltage source AC/DC converter.
  14. In claim 13, A method for adaptive linkage voltage and power control of multiple terminals in an AC and DC hybrid distribution system, characterized in that the above droop gain adjustment adjusts the amount of active power exchanged between the AC distribution system and the DC distribution system according to the rise or fall of the voltage of the DC distribution system.
  15. In claim 14, The method further includes a bus terminal voltage change amount calculation step for calculating the voltage change amount of a plurality of bus terminals connected to the voltage source AC/DC converter by means of a bus terminal voltage change amount calculation unit, and The rise or fall in voltage of the above DC distribution system reflects the voltage change amount of the above plurality of bus terminals, and A method for adaptive interconnection voltage and power control of multiple terminals in an AC and DC hybrid power distribution system, characterized in that the voltage change amount of each of the above-mentioned bus terminals is calculated by multiplying the power applied to the bus terminals by the voltage sensitivity factor (VSF) of each of the above-mentioned bus terminals.
  16. In claim 13, The above droop gain is determined by the ratio of the voltage change amount of a plurality of buses of the DC distribution system connected to the voltage source AC/DC converter to the amount of active power exchanged between the AC distribution system and the DC distribution system, and A method for adaptive interconnection voltage and power control of multiple terminals in an AC and DC hybrid distribution system, characterized in that the calculation of the above droop gain is repeated at time intervals predetermined by the above central energy management system (EMS).
  17. In claim 16, A method for adaptive interconnection voltage and power control of multiple terminals in an AC and DC hybrid distribution system, characterized in that the power flow analysis unit performs power flow analysis of the AC and DC distribution system by considering the operation of the voltage source AC/DC converter with the droop gain applied, which is periodically updated.
  18. In claim 15, A method for adaptive interconnection voltage and power control of multiple terminals in an AC and DC hybrid distribution system, characterized in that the above voltage sensitivity index (VSF) is the ratio of the voltage change amount at the second bus terminal to the power change amount at the first bus terminal.

Description

System and Method for Adaptive Voltage and Power Control of Multi-Terminals in AC and DC Hybrid Distribution System The present invention relates to the management of an AC and DC hybrid distribution system, and more specifically, to an adaptive voltage and power control system and method for the interconnection of multiple terminals in an AC and DC hybrid distribution system. The present invention relates to an AC/DC hybrid power distribution system that exchanges power between AC and DC power distribution systems. With the recent increase in distributed energy sources using direct current, such as renewable energy sources, energy storage devices, and electric vehicles, interest and research on DC distribution systems are growing due to their advantages in improving distribution system efficiency and control/management. To ensure the continuous expansion of distributed power sources and renewable energy, not only power sources but also the reinforcement of grid infrastructure for connection to the power grid must be considered. Since the expansion of renewable energy affects the stability of the entire grid and the spread of distributed energy near consumers is linked to the issue of expanding saturated distribution networks, it is necessary to build infrastructure that can secure grid stability and efficiency. Furthermore, as the concentration and increase of electricity demand intensifies due to the proliferation of high-density cities and compact cities, the operation and management of urban distribution network infrastructure is emerging as a critical issue. The current major challenge in switchboard systems is to increase the hosting capacity of Distributed Energy Resources (DERs) connected to the distribution system. An increase in DER connections causes overvoltage and overcurrent problems in the distribution system, which degrades system stability and worsens transmission efficiency. Therefore, there is a demand for a structure capable of ensuring voltage stability and improving capacity in complex AC and DC distribution systems, such as multi-terminals. Figure 1 is a diagram of the AC/DC hybrid power system configuration of the multi-terminal type of the present invention. Figure 2 is a simplified diagram of the AC/DC hybrid power system of Figure 1. FIG. 3 is a schematic diagram illustrating the configuration of a multi-terminal interconnected adaptive voltage and power control system in an AC and DC hybrid distribution system according to one embodiment of the present invention. FIG. 4 is a diagram illustrating the concept of power flow including forward current and reverse current in an AC and DC hybrid power distribution system according to one embodiment of the present invention. FIG. 5 is a diagram briefly illustrating voltage fluctuations in a distribution system due to the connection of distributed power sources according to one embodiment of the present invention. FIG. 6 is a diagram illustrating the concept of power control for droop gain adjustment according to one embodiment of the present invention. FIG. 7 is a diagram illustrating the exchange of power between an AC distribution system and a DC distribution system using the voltage source AC/DC converter of the multi-terminal of the present invention. FIG. 8 is a flowchart illustrating a method for adaptive voltage and power control of multiple terminals in an AC and DC hybrid distribution system according to an embodiment of the present invention. FIG. 9 is a drawing illustrating an exemplary computing device capable of implementing a device and/or system according to various embodiments of the present invention. The advantages and features of the present invention and the methods for achieving them will become clear by referring to the embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below but may be implemented in various different forms. These embodiments are provided merely to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention, and the present invention is defined only by the scope of the claims. Throughout the specification, the same reference numerals refer to the same components. The embodiments described herein will be described with reference to cross-sectional and/or plan views, which are exemplary illustrations of the invention. In the drawings, the thickness of the components is exaggerated for effective description of the technical content. Accordingly, the components illustrated in the drawings are schematic in nature, and the shapes of the components illustrated in the drawings are intended to illustrate specific forms of the components and are not intended to limit the scope of the invention. Although terms such as first, second, third, etc., have been used to describe various components in the various embodiments of this speci