Leakage Current Detection and Protection Circuit for DC Remote Power Supply System

Abstract

The invention discloses a leakage current detection protection circuit of a direct-current remote supply power system. The circuit comprises a leakage current sampling module, a positive ground leakage current detection protection module, a negative ground leakage current detection protection module, a leakage current protection signal reporting module, and an MCU control module for controlling shut-down operation of the direct-current remote supply system. The input terminals of the positive ground leakage current detection protection module and the negative ground leakage current detection protection module are respectively and electrically connected with the leakage current sampling module; the output terminals of the positive ground leakage current detection protection module and the negative ground leakage current detection protection module are respectively and electrically connected by the leakage current protection signal reporting module; and the leakage current protection signal reporting module and the MCU control module are electrically connected. According to the invention, the requirement that the impedance to the ground of the output positive-negative line is larger than 1-M ohm can be met, thereby realizing to-the-ground transmission suspension power supply outputting; and the probability of leakage current misoperation can be substantially reduced.

Description

technical field [0001] The invention relates to the communication field, in particular to a leakage current detection and protection circuit of a DC remote power supply system. Background technique [0002] In recent years, my country's communication industry has developed rapidly. The communication power supply is the infrastructure of the entire communication network and the guarantee for the normal and reliable operation of the entire communication and telecommunication network. With the popularization and development of the 3G network, the construction of mobile base stations, EPON and indoor and outdoor computer rooms The power supply and connection problems are all completed by the DC remote power supply system. Leakage will occur during the use of the system. In consideration of personal safety, leakage current protection in the DC remote power supply system is a mandatory indicator that must be met. The current industry standard requirements for leakage current prote...

AI Technical Summary

Problems solved by technology

[0003] At present, there are two main detection and protection methods for leakage current in the industry: one is to use the current unbalance of the output line pair to determine the leakage current, so as to realize the protection shutdown. There are many branch bypasses, and it is very easy to cause malfunction under the condition of ensuring high-precision current sampling, which has a great impact on the reliability of the DC remote power supply system

The second is designed by providing a current loop to the line to detect the leakage current for protection. The disadvantage of this method is that the output impedance to the ground is too small to meet the requirements of more than 1M ohms. The internal resistance of the insulation is too low. When the external impedance is small, there will be a large leakage current loop at the moment of protection, which poses a great safety hazard to the person.

[0004] To sum up, none of the leakage protection methods in the existing DC remote power supply system can guarantee personal safety, so they cannot meet the needs of the market

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