Abstract：Compared with large photovoltaic systems with isolation transformers，distributed photovoltaic

systems have small power and volume. In order to improve efficiency，non-insulated inverters are often used in

design，but photovoltaic leakage current endangering system safety is also generated. Taking the single-phase fullbridge photovoltaic system as an example，the generation mechanism of photovoltaic leakage current was analyzed in detail through in-depth discussion of the problem of photovoltaic leakage current. Subsequently，the waveform characteristics of the photovoltaic leakage current entering the distribution network were analyzed，and a

photovoltaic leakage current monitoring method based on Hausdorff distance was proposed，which simply and

efficiently solved the problem of photovoltaic leakage current monitoring and protection. Finally，the feasibility of

the proposed method was verified by simulation analysis.

      Key words：non-isolated；distributed PV；inverter circuit；leakage current monitoring；Hausdorff distance