井下供电系统漏电保护方案分析（Analysis of leakage protection scheme for underground power supply system）.doc

井下供电系统漏电保护方案分析（Analysis of leakage protection scheme for underground power supply system） Analysis of leakage protection scheme for underground power supply system Preface Leakage protection in underground coal mine is one of the three basic electrical protection, its main purpose is to prevent personal casualty, avoid the leakage current of gas and coal dust detonated by cutting off the power supply operation, ensure the mine production and safety. Therefore, the use of perfect leakage protection scheme is an important measure to ensure the safety of coal mine power supply system. 1, the basic requirements of leakage protection As the category of relay protection, leakage protection should be the same as other relay protection devices, and it should meet the requirements of safety, reliability, selectivity and reliability. The so-called security refers to the leakage protection from the most serious personal electric shock accident to the current time multiplied by the power supply is removed through the human body should be less than 30MA.S; for the single-phase grounding fault and other leakage, should ensure that the power off or the occurrence of intermittent leakage, leakage spark energy less than 0.28MJ ground. The so-called reliability refers to the leakage protection device itself has a certain degree of reliability, for the protection of the unit when the leakage fault can not be refused to move; and when the protection of any fault outside the unit can not be mistakenly move. The so-called sensitivity refers to the leakage protection device has a strong ability to respond to the critical leakage fault. The so-called selective means that the leakage protection device only removes the power supply of the leakage part in the power supply unit Reserve the power source of the non leakage part. Whether it is radial power supply or trunk type power supply, the power failure range can be reduced as much as possible. 2. Analysis of current leakage protection devic