A Coordinated Control Method Applicable to Flexible DC Distribution System

Abstract

The invention discloses a coordinated control method suitable for a flexible direct current power distribution system, including upper layer control at the system level and bottom layer control at the converter level, wherein the specific operation of the upper layer control at the system level is: by calculating the optimal power flow The control reference value of the bottom-level converter is given, and the DC voltage of the intermediate node is controlled by controlling the bottom-level converter to make it stable; the specific operation of the bottom-level control of the converter level is: to determine the stable operating point of the VSC converter, When the load power changes, the power distribution coefficient K of the VSC converter determines the power change ratio of the VSC converter when the load power changes. By setting the power distribution coefficient K of the VSC converter and the intermediate node voltage to reduce the system The method can meet the control requirements of the flexible DC power distribution system and ensure the stability of the system operation.

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

Images