Method and system for switching microgrid between island mode and grid connected mode

Abstract

The invention, belonging to the field of dispatching and management of a distribution network, provides a method and system for switching a microgrid between an island mode and a grid connected mode. When an external electric network has a fault, distributed power in a microgrid system is cut off, a grid connected contact breaker of the microgrid system and the external electric network is opened, a voltage and a frequency of the microgrid system are regenerated by a main power switching control mode in the microgrid system, and the microgrid system works independently; and when the external electric network returns to normal, if the electric network side voltage of the grid connected contact breaker is monitored to be normal and is lasted for a certain time, operations of a fan, a photovoltaic power generation system and an energy storage system of a storage battery are stopped, the grid connected contact breaker of the microgrid system is closed, a load is powered with the external electric network, the devices such as the fan and the like are reconnected to the grid for operation, so that a stable operation of the microgrid system in a transient state process of switching between the island mode and the grid connected mode is satisfied, the transient time is shortened, and the requirements of the microgrid system in safety, reliability and quick response are satisfied. The method and system have the characteristics of quickness, stability and reliability.

Description

technical field [0001] The invention belongs to the field of dispatching and management of distribution networks, and in particular relates to a method and system for switching microgrids between island and grid-connected modes. Background technique [0002] In the grid-connected operation mode of the micro-grid system, when a power outage occurs in the large power grid, it is necessary to quickly disconnect from the large power grid and switch to the island operation mode to ensure reliable power supply of the micro-grid load; in the island operation mode, when the large power grid recovers After it is normal, it should be quickly switched to the grid-connected operation mode. [0003] The existing micro-grid system is irrational in the mutual switching between island and grid-connected modes. For example, the switching time is long, and the load will experience intermittent power outages. It is difficult to meet the requirements of safe, reliable and fast response of the m...

AI Technical Summary

Problems solved by technology

[0004] The present invention provides a method and system for switching microgrids between island and grid-connected modes, aiming to solve the irrationality of mutual switching between isolated island and grid-connected modes of microgrid systems provided by the prior art , the switching time is long, the load will have intermittent power outages, and it is difficult to meet the requirements of safety, reliability and rapid response of the microgrid system

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