Winding fault detection in coupled inductors using a single flux sensor

This paper presents a technique based on leakage flux to detect the winding fault in coupled inductors using a single flux sensor. An analytical model is developed and analysis on leakage flux for different load conditions and severity of fault is carried out. Using the developed model a comparative study of leakage flux at the outer limb and center of the yoke under the winding fault is carried out. The simulation study revealed that leakage flux at center of the yoke is found to be effective in identifying the fault. The analytical model is validated experimentally by using a three phase, star connected 1.2 H, 2.2 A coupled inductor. Both analytical model based and experimentally obtained results are found to follow the same trend in leakage flux during the winding short circuit conditions. The trend has been verified for different loading and severity conditions. The proposed technique is relatively simple to implement in real-time. The technique requires a single, inexpensive and low bandwidth hall-effect based flux sensor and is capable of detecting winding abnormality in a three phase coupled inductor.