A multi-microgrid flexible interconnection system and control method thereof

Abstract

The present invention provides a multi-microgrid flexible interconnection system and a control method thereof. The system includes a plurality of microgrids and multi-port flexible interconnectors, wherein the multi-port flexible interconnectors are arranged between the feeder lines of the plurality of microgrids; and the multi-port flexible interconnectors are connected into the tail ends of the adjacent feeder lines of the plurality of microgrids, so that the flexible interconnection of the plurality of microgrids is realized. According to the multi-microgrid flexible interconnection system and the control method thereof of the invention, the multi-port flexible interconnectors, replacing traditional contact switches, are connected into the tail ends of the adjacent feeder lines between the different microgrids, so that the flexible interconnection of the plurality of microgrids is realized; due to the controllability of power electronic devices, power flow interaction among the plurality of microgrids can be realized. With the multi-microgrid flexible interconnection system and the control method thereof of the invention, multi-microgrid loop network operation can be realized with no short-circuit current increased; the local absorbing capacity of new energy resources can be improved; load balance between the feeder lines can be improved; mutual backup and mutual power supply of the adjacent microgrids can be realized; line loss can be decreased; the reliability of power supply can be improved; and voltage quality at the tail ends of the feeder lines can be maintained.

Description

technical field [0001] The present invention relates to the field of micro-grid technology and power electronics technology in power systems, and in particular to a multi-micro-grid flexible interconnection system realized by using power electronic devices and a control method thereof. Background technique [0002] In multiple microgrids, the feeder ends of adjacent microgrids are often interconnected through tie switches. Traditional tie switches have the following functions: [0003] 1. If a microgrid system fails, transfer the load of the faulty system to another load through the contact switch to improve the reliability of power supply; [0004] 2. Through the coordination and cooperation of multiple contact switches, network reconstruction is realized and system operation is optimized. [0005] In fact, considering factors such as the electromagnetic ring network and short-circuit current, the contact switch must be in the off state under normal working conditions, tha...

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Problems solved by technology

[0006] However, with the massive access of new energy to microgrids and users' demands for high power quality, traditional contact switches cannot meet the requirements in terms of control capability and response speed. Flexible interconnection of multiple microgrids is required to realize the power flow between feeders. Flexible interaction

[0007] After retrieval, the article "Increasing distributed generation penetration using soft normally-open points" (IEEE Power and Energy Society General Meeting, 2010) published by Jeffrey M. Bloemink et al. proposed to use SNOP (soft normally open switch) to replace traditional distribution network feeder The contact switch is a solution to realize the flexible interconnection of the distribution network feeder end, but it does not involve the elaboration of the multi-microgrid flexible interconnection solution. Due to the different installation locations, there are also differences in design and control.

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