Residual current protection device is an effective measure to prevent electric shock. All countries in the world and the International Electrotechnical Commission (IEC) have made great efforts to promote the use of residual current operated protectors in low-voltage power grids by formulating corresponding electrical installation regulations and power consumption regulations. China's residual current protector (RCD) has been developed since the mid-1970s, and first applied in rural low-voltage power grid. After continuous improvement and development from 1980s to 1990s, a product system of RCD with perfect varieties, complete specifications and in line with IEC international standards has been formed. It plays an important role in the security protection of low-voltage power grid, especially in rural low-voltage power grid.

From the development of domestic residual current protector, the quantity and variety of residual current protector in China can basically meet the needs of national economic development, and play a huge role in the security protection of power grid. China's rural low-voltage and low-voltage power grid leakage protection now mainly adopts primary general protection. With the realization of rural electrification and the arrival of the information age, household appliances and home computers are increasingly popular in urban and rural households, and the requirements for the reliability and continuity of power supply will be higher and higher.