Coordinated control method for low-voltage flexible distribution network power supply system

Abstract

The invention provides a coordinated control method for a low-voltage flexible distribution network power supply system. The system comprises four distribution transformers T1-T4, four sections of 400V low-voltage AC (alternating current) buses and four flexible DC (direct current) converters, wherein the four sections of 400V low-voltage AC buses are connected through bus coupler switches; a DC bus is further connected to an energy storage system and a distributed photovoltaic system. The coordinated control method is used for performing coordinated control for different fault conditions of bus coupler switch fault, incoming line power loss, flexible direct current converter fault, energy storage converter fault and photovoltaic converter fault in different operation modes. According to the system, interconnection of multiple lines of the distribution network is realized by the flexible DC converters, power wheeling support between the lines is realized, and after a certain distribution line fails and breaks, the flexible DC converters perform islanded operation with load; meanwhile, interconnection is realized on the DC link with photovoltaic and energy storage systems, and an optical storage and flexible DC combined hybrid system is formed.

Description

technical field [0001] The invention belongs to the technical field of flexible power transmission, and in particular relates to a coordinated control method for a low-voltage flexible distribution network power supply system. Background technique [0002] Due to its unique technical advantages, flexible DC transmission is introduced into the urban power grid with intensive power consumption, and its rapid controllability is used to solve the problems of power supply difficulties, high costs and difficult power flow control in urban power supply. There are also broad application prospects in power distribution. First, the active power transmitted by flexible DC transmission can be quickly and flexibly controlled, and the power flow between different lines in the distribution network can be effectively and feasiblely allocated; secondly, flexible DC transmission can dynamically compensate the AC bus. The reactive power is conducive to the grid-connection of distributed power ...

AI Technical Summary

Problems solved by technology

The traditional power distribution network has the following problems: 1) The main transformer corresponding to a bus with a light load (for example, during the day on a working day) works in a light-load or no-load state, and the efficiency is low; 2) When two low-voltage buses When the total load exceeds the capacity of a single main transformer, at this time, due to the failure of a certain incoming line or the failure of the main transformer, the bus tie switch is closed, which will easily cause the single main transformer to be overloaded or even tripped d

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