The study on island detection for distributed power combining power line zero-crossing communication technology

Renewable distributed power has the characters of cleanliness and environmental protection, it can also improve stability and flexibility of the whole power system. It is more reliable to realize information exchange between the main grid and distributed power by communication. Aiming at the problem, the paper uses the feature of extremely strong decay resistance for the power line zero-crossing communication signal and combines time-frequency analysis to make distributed power fast detect the change of the main power supply state by estimating whether these distributed powers receive zero-crossing communication signal or not. Meanwhile, frequency measurement of power system is conducted based on complex wavelet transform and least square fitting method. On the implementation method, the power line zero-crossing communication signal detecting platform of distributed power is nearly consistent with electric energy meter and doesn't need special communication signal receiving device.