Coordination control method suitable for flexible direct-current power distribution system

Abstract

The invention discloses a coordination control method suitable for a flexible direct-current power distribution system. The method comprises system-level upper-layer control and converter-level bottom-layer control, wherein the specific operation of the system-level upper-layer control comprises the steps of giving a control reference value of a bottom-layer converter by calculating an optimal power flow, and controlling a direct-current voltage of a middle node by controlling the bottom-layer converter so as to stabilize the direct-current voltage; the specific operation of the converter-level bottom-layer control comprises the steps of determining a stable operation point of the VSC converter, setting that the power distribution coefficient K of the VSC when the load power changes determines the power change proportion of the VSC when the load power changes, and by setting the power distribution coefficient K of the VSC converter and the intermediate node voltage, reducing the DC voltage offset of other converters caused by the power change of a certain converter of the system. The method can meet the control requirements of the flexible direct-current power distribution system,and the stability of the system operation is ensured.

Description

technical field [0001] The invention belongs to the field of power system control, and in particular relates to a coordinated control method suitable for a flexible DC power distribution system. Background technique [0002] At present, my country's energy industry is undergoing important changes. The energy crisis and the aggravation of environmental pollution have made the use of renewable energy such as wind power, photovoltaics, and hydropower an important direction for the development of the energy industry. With the continuous research and exploration of distributed power generation technology by domestic and foreign researchers, distributed power generation technology has been improved day by day. As new energy grid-connected power generation is connected to the power distribution system, and the proportion of DC loads is increasing day by day (such as electric vehicles, LED lights, etc.), the power conversion links in the AC distribution network will increase accordi...

AI Technical Summary

Problems solved by technology

The core of master-slave control and voltage margin control is to control the DC voltage of each station in the system through a single converter station, and it is necessary to switch the constant voltage converter station in case of failure; the droop control controls the system through multiple converter stations. Adjustment can ensure the continuity of electrical quantity regulation and reduce the transient process that may be caused by sudden changes in electrical quantity, but it also has the disadvantage that the power flow is difficult to accurately control, and it is difficult to determine the stable operating point of the DC system, which is greatly affected by line resistance The problem

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