Micro-grid self-healing control method based on island and frequency drop

Abstract

The invention provides a micro-grid self-healing control method based on an island and frequency drop, and the method comprises the steps of: building a mathematical model of a micro-power interface inverter, and achieving the control of the micro-power interface inverter; for micro-grid systems with different voltage levels, evaluating the influence on the transmission characteristics of the micro-power supply power; constructing a power transmission module and a voltage and current double-loop control module of a droop controller; based on an improved droop control strategy, introducing the output current feedback of the inverter outside the voltage and current double-loop control module, and adding a virtual reactance loop; before grid connection of the inverter, increasing the steady state of the inductance value of a virtual connection line, then reducing the virtual inductance value to enable the phase shift of the output voltage of the inverter and the bus voltage to be within a set range; according to the invention, the stability of the voltage amplitude and frequency of the island microgrid system can be realized, the dynamic response speed of the system can be improved, and the steady-state error is smaller; when the load power suddenly changes, the load power can be precisely and reasonably distributed, and the output power of the micro-power supply is smoother.

Description

technical field [0001] The invention relates to the field of intelligent distribution network, in particular to a micro-grid self-healing control method based on islanding and frequency drop. Background technique [0002] With the development of photovoltaic, wind power and other new energy power generation technologies, distributed new energy power generation technology has attracted widespread attention due to its advantages of high power generation efficiency, flexibility and reliability, advanced technology, energy saving and environmental protection. Each power generation equipment in the distributed power generation system is independent of each other, which greatly improves its safety and reliability, and makes up for the lack of stability of the large power grid. Moreover, the construction and installation costs of the distributed power generation system are low, the power generation method is flexible, and compared with the large power grid, the transmission and dis...

AI Technical Summary

Problems solved by technology

However, due to the intermittency of various micro-power sources, the extensive use of power electronic devices, and the variability of loads in the island microgrid, the voltage and frequency fluctuate in a large range, and even frequency collapse and voltage collapse occur, which is largely limited. The large-scale application and promotion of microgrid

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