Multi-distributed-power-supply island detection method based on inverter frequency control

Abstract

The invention discloses a multi-distributed-power- supply island detection method based on inverter frequency control, and belongs to the technical field of anti-island protection. The method is characterized by comprising the following steps: a, determining a main inverter; b, obtaining a reactive power difference value; c, obtaining the PI adjusting value of the reactive power difference value and the absolute value |delta Q'| of the PI adjusting value; d, judging whether |delta Q'| is greater than or equal to a first threshold, if yes, respectively executing the step e and the step f, and otherwise, returning to execute the step; e, enabling an inverter to carry out reactive power positive feedback; f, judging whether |delta Q'| is greater than or equal to a second threshold, if yes, executing a step g, and otherwise, returning to the step b; and g, cutting off distributed power supplies. According to the multi-distributed-power-supply island detection method based on inverter frequency control, after a multi-distributed-power-supply island effect occurs, a main inverter can stabilize the island frequency, the dilution effect can be effectively avoided, and non-blind area detection of the multi-distributed-power-supply island is achieved.

Description

technical field [0001] The invention relates to an islanding detection method for multiple distributed power sources based on inverter frequency control, which belongs to the technical field of anti-islanding protection. Background technique [0002] Anti-islanding protection is a kind of protection that needs to be configured during the grid-connected operation of distributed power sources. When the power supply is interrupted due to faults or maintenance of the grid, if the distributed power sources are not cut off in time, the distributed power sources will continue to transmit power to the grid, bringing The risk of "reverse power transmission" will bring safety hazards to maintenance personnel on the one hand, and on the other hand, due to the influence of light intensity and temperature, the output power of the inverter has fluctuations, and the voltage caused by the unbalanced island power And the frequency limit is easy to damage the electrical equipment. Therefore,...

AI Technical Summary

Problems solved by technology

[0004] However, in the prior art, for the island detection of multiple distributed power sources, the dilution effect of multiple distributed power sources is prone to occur during the detection process, resulting in a large detection blind area

Therefore, in the detection of multiple distributed power islands, it is an urgent problem to be solved in this field to design a technical solution that can eliminate the dilution effect and avoid large detection blind spots.

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