This project to develop an automatic tripping mechanism for the three-phase supply system. The project output reset automatically after a brief interruption in the event temporary fault while it remains in tripped condition in case of permanent fault. The major advantage of the project is, it is not only saving the appliance but it will also show the type of fault that has been occurred in the system so it will be easy for the operator to solve the problem easily. It will also check whether the fault is permanent or temporary fault. If the fault is temporary fault, then the supply will be restored after a predefined time of 15sec otherwise permanent trip signal is given to the relay. The demand of electrical power is increasing day by day for households, agricultural, commercial, industry sectors etc. This paper is developed in order to maintain that electrical power required by these sectors, as in an electrical system, due to line to ground (L-G), line to line fault (L-L), three lines (LLL) various fault occurs. In this paper it has been discussed how to overcome this problem and for this a system is built, which has an auto reclosing mechanism of disconnecting the supply to avoid large scale damage to the control gears, load or manpower in the grid substations. In this way a tripping mechanism is made in order to curb temporary and permanent faults. Three phase fault analysis and its protection mechanism main function is to ensure safety of equipment’s and maintain power system stability at high speed. In order to protect the equipment’s of power system from faults, knowledge about system faults, their detection, and safe isolation of the faulted area is needed. A semi-permanent fault can be effectuated when a small branch of tree falls on line. In such case of permanent fault, the fault can’t be cleared by an instantaneous de-energizing of the line and subsequent auto reclosing. If there is a compeered time-delayed trip then system would let the branch to be burned away without any harm to the existing system. On an overhead line, a broken wire or conductor making a phase open, or a broken pole making the phases to short are the example of common and most often occurring permanent fault. Most of the faults can be successfully cleared by using the appropriate tripping and auto reclosing mechanism. Proper tripping can de- energize the line for enough time period to pass the fault source and to de-energize the fault arc, then the system automatically recloses the line to maintain the power supply. In the present scenario of power systems, automatic reclosing system has a very wide area where it can be applied.