Microgrid distributed system protection method and device

Abstract

The invention provides a microgrid distributed system protection method and device and relates to the technical field of power system protection. The method is applied to any stage of protection unitexcept a bus protection unit in microgrid distributed system protection equipment, and the protection equipment comprises multiple stages of protection units which are arranged according to voltage grading of a microgrid distributed system; the method comprises the following steps: detecting fault information in the microgrid distributed system, the fault information comprising island sign information; sending the fault information to an upper-level protection unit to enable the upper-level protection unit to generate a protection instruction according to the fault information; and receiving aprotection instruction, and executing a protection action according to the protection instruction. According to the invention, the microgrid protection equipment is subdivided into different levels of protection units with independent relative functions, each level of protection unit has detection, protection and control functions, and because the protection units are more independent and flexible, the equipment does not have a protection dead zone, and the protection reliability is improved.

Description

technical field [0001] The invention relates to the technical field of power system protection, in particular to a method and device for protecting a distributed system of a microgrid. Background technique [0002] Microgrid is a new type of network structure, which is a system unit composed of a group of micro power sources, loads, and energy storage system control devices. The power sources in the microgrid are mostly distributed power sources with small capacity, that is, small units with power electronic interfaces, including micro gas turbines, fuel wires, photovoltaic cells, small wind turbines, and energy storage devices such as supercapacitors, flywheels, and batteries. , They are connected to the user side, and have the characteristics of low cost, low voltage and low pollution. The development and extension of microgrid can promote the large-scale access of distributed power and renewable energy, and realize the highly reliable supply of various energy sources. g...

AI Technical Summary

Problems solved by technology

[0003] The microgrid protection has certain particularities. Due to the island operation mode of the microgrid and the large number of distributed power sources connected, the characteristics of the fault current are not obvious, and the direction of the current path cannot be determined, which makes the traditional protection strategy in the distribution network In the case of malfunction or refusal to operate, the three-stage overcurrent protection in the traditional power grid cannot be directly applied to the microgrid, and the reliability of the protection equipment of the distributed system of the microgrid is poor

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