Based on the analysis and introduction of the classification, performance parameters and development trends of residual current protectors at home and abroad, this paper puts forward the development direction of residual current protectors in China at present, especially the problems that should be paid attention to when developing residual current protectors to meet the needs of the reform of rural and urban agricultural networks.
Installing residual current action protector (hereinafter referred to as residual current protector) in low-voltage power grid is an effective protective measure to prevent electric shock, electrical fire and damage of electrical equipment.The use of residual current action protectors in low-voltage power grids is widely promoted by the world and the international electrotechnical commission through the formulation of corresponding electrical installation regulations and electricity usage regulations.China's residual current protector began to develop in the mid-1970s, and was first popularized and applied in rural low-voltage power grids. After continuous improvement and development from the 1980s to the 1990s, it has formed a series of residual current protector products with complete varieties and specifications that conform to IEC international standards.It plays an important role in the safety protection of low-voltage network, especially in rural areas.
From the development of domestic residual current protectors, China's residual current protectors can basically meet the needs of national economic development in terms of number and variety, and play a huge role in the security protection of the power grid.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 on the reliability and continuity of power supply will be increasingly high.
Using pulse type and amplitude type residual current protector as the primary general protection, the fault action is relatively more, the trip is frequent, the power failure surface after the action is large, so the contradiction of power supply reliability will be more and more prominent.With the development of rural economy and the gradual popularization of residual current circuit breakers, the leakage protection form of rural low-voltage power grid should gradually transition from primary protection to secondary protection or tertiary protection composed of primary protection, branch protection and terminal protection.The residual current circuit breaker with overload, short circuit and leakage protection should be widely used for general protection and branch protection. The operating current is 100 ~ 300mA, and the operating time is delay type. The total protection delay time is about 0.2 ~ 0.3s, and the branch protection delay time is about 0.2s.Terminal protection shall be the general type of residual current circuit breaker for household use, which may be used with overload and short-circuit protection, or residual current circuit breaker without overcurrent protection, and in addition, mini-circuit breaker to provide overload and short-circuit protection, the operating current shall not be greater than 30mA, the operating time shall not be greater than 0.1s.
The main protection, branch protection and terminal protection coordinate in the action time and action current, which can meet the requirements of selective protection.
The implementation of hierarchical protection will significantly reduce the number of power outages caused by improper operation of protective devices and limit the failure area to the minimum range so as to greatly improve the safety level of the power grid and the quality of power supply.Residual current circuit breaker combines the function of detecting residual current with the function of disconnecting the main circuit, and can also overload and short-circuit protection of the circuit, which can not only reduce the volume of the device, reduce the manufacturing cost, but also greatly improve the protection level of the power grid.In order to speed up the implementation of hierarchical protection, manufacturers and users of residual current protector products should cooperate with each other and actively develop delay residual current circuit breakers with reliable performance and stable operation time to meet the needs of trunk and branch line protection.For household residual current circuit breaker, manufacturers and users should work together to get rid of the circle of low price competition, managed to improve the anti-jamming ability and reliability efforts to further improve the performance of our products and to strengthen the operation management of residual current circuit breaker and after-sales service, make the rural power grid through the technical renovation, equipment level and the security level to produce a qualitative leap.
This article is excerpted from "report on China leakage protection plug market research and investment prospects for 2018-2024"