Automatic Fault Detection And Protecton In Three Phase Induction Motor

Abstract

An induction or asynchronous motor is an AC electric motor in which the electric current in the rotor needed to produce torque is obtained by electromagnetic induction from the magnetic field of the stator winding. Various studies have shown that anywhere from 70%, to as high as 90%, of faults on most overhead lines are transient. Three-phase induction (asynchronous) motors are industrial work-horses, responsible for consumption of 40–50% of generated electrical power. There are different kinds of induction motor faults, broadly classified as rotor and stator faults. The source of such faults could be external and/or internal due to various electrical, environmental, mechanical reasons. A transient fault, such as an insulator flashover, is a fault which is cleared by the immediate tripping of one or more circuit breakers to isolate the fault, and which does not recur when the line is re-energized. Faults tend to be less transient (near the 80% range) at lower, distribution voltages and more transient (near the 90% range) at higher, sub transmission and transmission voltages. In the present paper, automatic fault detective analysis for protection of three phase induction motor has been investigated and experimental set up have been carried out for the required detective analysis by using PIC18F452 microcontroller and has also been shown in C Programming. The normal and abnormal conditions of voltage and current parameters for 3ϕ, 415V,  HP induction motor have been discussed based upon the performance of present investigation. It has been found that under short circuit and under/over voltage conditions, the current/voltage through the respective phases are differ from the normal operating conditions.