Method for implementing master-slave control for microgrid under islanding condition

Abstract

The invention relates to a method for implementing master-slave control for a microgrid under an islanding condition, which realizes master-slave operations of a plurality of parallelly connected DGs (distributed generations) in the microgrid, wherein each DG adopts a segmented novel droop control method which comprises improved droop control and traditional droop control, the DG acting as a master control unit stays at an improved droop control state, and the DGs acting as slave control units stay at a traditional droop control state. In the improved droop control, P-f control adopts a method of automatically adjusting a droop factor of a P-f curve so as to realize maintenance for system frequency f, and Q-V control adopts a method of parallelly changing droop external characteristics so as to realize maintenance for system voltage V. Compared with the prior art, the method provided by the invention is used for solving substantial changes in frequency and voltage caused by load or mode conversion in the operating process of the microgrid, thereby improving the quality of electric energy of the microgrid.

Description

technical field [0001] The invention relates to the field of coordinated control of new energy power generation, in particular to a method for realizing master-slave control of a microgrid under isolated island conditions. Background technique [0002] With the in-depth research on distributed power generation and corresponding distributed energy storage technology, a special grid form "micro-grid" formed by integrating distributed power generation related technologies has gradually formed. In order to make more reasonable and effective use of distributed power, some scholars have conducted a lot of research on the concept of "microgrid". There are two main operation modes of microgrid, namely grid-connected operation mode and island operation mode. Both of these two modes need to control the distributed power sources inside the microgrid. The coordinated control strategies of the microgrid mainly include master-slave control, peer-to-peer control and hierarchical control. ...

AI Technical Summary

Problems solved by technology

[0004] Traditional master-slave control is mainly used for PQ control and Vf control, and does not consider droop control

For the droop control method in the peer-to-peer network, there will be a large power shortage no matter when it is disconnected from the grid or when the load carried by the island operation changes greatly, which will cause a large increase in the overall frequency and voltage of the microgrid. Amplitude changes, which cannot meet the requirements of power quality

In addition, a single master-slave network depends too much on the master micro power supply. If the capacity of the master micro power supply is small, the stability of the system cannot be guaranteed.

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