Modal switching method, modal switching device, and back-to-back device

Abstract

The present application provides a modal switching method, a modal switching device and a back-to-back device. The modal switching method comprises the following steps: detecting whether a fault occurs in a first low-voltage AC distribution network in real time; if no fault is detected in the first low-voltage AC distribution network, judging whether the received signal from the second converter is a signal the second low-voltage AC distribution network is faulty; and if the received signal from the second converter is a signal that the second low-voltage AC distribution network is faulty, switching the first control mode of the first converter to the third control mode. According to the model switching method provided by the embodiment of the present application, by adoption of a power-voltage control seamless mode switching strategy, when the fault occurs in the low-voltage AC distribution network, the current power control mode can be seamlessly switched to the voltage control mode,which is not only little affected by the fault detection closing value and communication delay, but also can smoothly and reliably realize the fault mode switching, and the reliability of energy sharing between the interconnected low-voltage AC distribution networks can be improved.

Description

Technical field [0001] This application relates to the technical field of low-voltage AC distribution network control, and more specifically, to a modal switching method, a modal switching device, and back-to-back equipment. Background technique [0002] The development of microgrids or distributed photovoltaic power generation in low-voltage AC distribution networks (usually called transformer districts, TDs) can effectively promote the development of new energy industries, improve clean power, and achieve energy conservation and environmental protection. However, due to the large difference in power consumption characteristics of each distribution station area, some distribution station areas cannot absorb all the photovoltaic output during the peak period of photovoltaic output and reverse power to the superior grid, which may trigger the malfunction of the protection device, and At the same time, other parts of the heavy-duty platform area may still need the power grid to pro...

AI Technical Summary

Problems solved by technology

However, due to the large difference in power consumption characteristics of each distribution station area, some distribution station areas cannot absorb all the photovoltaic output during the peak period of photovoltaic output and send power back to the upper grid, which may trigger the protection device to malfunction. At the same time, other heavy-duty station areas may still require a large power supply from the grid

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