Layered direct-current power transmission system

Abstract

The invention belongs to the field of power system power transmission and distribution. The invention provides a layered direct-current power transmission system used for transmitting a large amount of renewable energy power generation distributed in different regions to a load center. The system is formed by interconnecting a high-voltage converter station and a plurality of low-voltage converterstations, and the high-voltage converter station is formed by connecting a high-end converter and a low-end converter in series. A direct-current port of the high-voltage converter station is connected to a direct-current port of the receiving-end power grid high-voltage converter station through a direct-current transmission line; the low-end converter of the high-voltage converter station is connected with the direct-current side of one or more low-voltage converter stations through a direct-current transmission line, the alternating-current side of each low-voltage converter station is connected with the alternating-current system of each low-voltage converter station, and the high-end converter of the high-voltage converter station and the alternating-current side of the low-end converter are connected to the alternating-current system where the high-voltage converter station is located. According to the topology, the geographic position of each renewable energy power station canbe arranged more conveniently, alternating current side isolation of each renewable energy power station is realized, and the total capacity of a voltage source type converter in the whole system is reduced.

Description

technical field [0001] The invention belongs to the field of electric power transmission and distribution, and in particular relates to a layered DC power transmission system, which is used to transmit power generation of a large amount of renewable energy distributed in different regions to a load center. Background technique [0002] my country is currently facing a severe smog problem. One of the main reasons for the smog problem is that our country relies too much on coal and other fossil energy sources. Vigorously developing renewable energy such as solar power, wind power, and hydropower is the solution to the smog problem in our country. fundamental measures. Northwest China has a lot of wind power and solar power resources, and Southwest China has a lot of hydropower, wind power and solar power resources. Taking the five provinces of Inner Mongolia, Xinjiang, Gansu, Qinghai and Ningxia as examples, the exploitable capacity of wind energy and photovoltaic power genera...

AI Technical Summary

Problems solved by technology

[0006] 1. It is necessary to build a large-capacity voltage source converter station to facilitate access to wind power, photovoltaic power generation and other new energy power generation systems, which brings high costs and high losses;

[0007] 2. Each power station needs to be connected to the AC side of the voltage source converter station through its own long-distance AC transmission line. Since the long-distance AC transmission line will generate a large amount of reactive power, and the AC transmission line is a three-phase line, Each AC transmission line contains 3 wires, resulting in large loss of transmission lines, high cost, and difficulty in line erection;

[0008] 3. Since each power station is interconnected through AC transmission lines, any AC fault will affect all power stations, resulting in poor system stability and reliability

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