Island effect detection method based on active frequency deviation and its device

Abstract

A detached island effect test method and a device based on active frequency deviation relate to a test method and a device to test distributive new energy grid integration power supply, in particular to a detached island effect test method and a device based on active frequency deviation. Regarding the utility model, 25 cyclic waves form a major cycle. Chopped wave rate cf of the first 15 cyclic waves is 0, and variance trend of the frequency is tested. Under the circumstance that frequency tends to rise, frequency disturbance with the chopped wave rate of cf is added in the grid frequency inthe last ten cyclic waves, and initial value cfmax of the chopped wave rate cf is positive. Under the circumstance that the frequency tends to reduce, frequency disturbance with the chopped wave rateof cf is added in the grid frequency in the last ten cyclic waves, and initial value cfmin of the chopped wave rate cf is negative. By adopting the invention, not only the operation probability of the detached island tested is improved; but also testing time is reduced, and current harmonics injected into the grid is reduced.

Description

Islanding effect detection method and device based on active frequency offset technical field The invention relates to a measurement and control method and device for distributed new energy grid-connected power supply, in particular to an islanding effect detection method and device based on active frequency offset. Background technique Distributed power generation systems composed of new energy sources are attracting more and more attention, especially wind power and solar grid-connected power generation. This is because: (1) The demand for electricity is increasing day by day, and non-renewable energy sources such as coal and oil are becoming exhausted, and it is imminent to seek alternative energy sources; (2) The environmental pollution caused by traditional centralized and large-scale fuel power generation has seriously affected society. For production and life, green new energy can help relieve environmental pressure; (3) Due to the wide distribution and low density ...

AI Technical Summary

Problems solved by technology

That is, when the system load satisfies formula (10), there is no phase difference between Va and iPV, and the system frequency remains unchanged, entering the detection blind zone

2. Disadvantages of AFD method

The above shortcomings show that the AFD method provides a good idea for island detection, but still needs further improvement

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