Multi-strategy photovoltaic microgrid protection method and system

Abstract

The invention relates to the technical field of power generation of a photovoltaic microgrid, and discloses a multi-strategy photovoltaic microgrid protection method and system. The photovoltaic microgrid protection method comprises the steps of dividing the microgrid into two protection layers, wherein the two protection layers comprise global information-based concentrated protection layer (1) and a single point information quantity-based protection layer (2); and receiving all information acquired by the single point information quantity-based protection layer (2) by the global information-based concentrated protection layer (1), and performing protection after summarization. By the multi-strategy photovoltaic microgrid protection method and system, concentrated and discrete integral protection is achieved, and all information of the microgrid is integrally used.

Description

technical field [0001] The present invention relates to the technical field of photovoltaic micro-grid power generation, in particular, to a multi-strategy photovoltaic micro-grid protection method and a multi-strategy photovoltaic micro-grid protection system using the method. Background technique [0002] The microgrid is composed of distributed energy, load and power transmission and distribution system, which can operate independently or in parallel with the large power grid, and has the function of coordinating and optimizing the control of internal power supply and load. The microgrid system is an organic system composed of various distributed power sources, energy storage devices, control and protection equipment, and loads. [0003] Microgrid access to the distribution network will have an impact on the relay protection of the microgrid. First, a large number of micro-grids in the micro-grid will provide fault current to the fault point, making the flow of power flo...

AI Technical Summary

Problems solved by technology

However, this method is often not suitable for variable microgrids. When DGs with unstable output start and stop frequently, the actual structure of the network also changes in real time, and the adjustment becomes very difficult.

Especially when a branch in the microgrid is disconnected due to faults and other reasons to generate an unplanned island, the sum of active and reactive power generated by the power generation device in the unplanned island does not necessarily match the internal load, which may cause frequency and voltage in the island. fluctuations, affecting power quality

The voltage and current measured in the protection device may also change accordingly, resulting in the malfunction of the device

Therefore, the central manager of the microgrid needs to make centralized decisions based on information such as the power flow distribution before the failure, the output power of the micropower supply, and the load situation, as well as the actual measurement information of the network. Output, etc., coupled with the limited short-circuit current provided by the inverter distributed power supply, pose serious challenges to the traditional current protection scheme in the microgrid island operation mode

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