Analysis and Test of Short-Circuit Fault Between Strands of Stator Bar Based on the Characteristic of End Leakage Magnetic Field

Abstract

As the demand for high efficiency and power density in AC motors grows, stator windings are increasingly using transposition bars to reduce winding losses. The bar is typically designed as a tight compact construction with several strands transposed in various ways. When a short-circuit fault occurs between the strands, establishing fault location and timely warning are key issues to ensure the safe operation of the motor. If the fault is not discovered and corrected promptly, it will deteriorate the winding faults and have more serious effects. This paper presented a method for detecting short-circuit faults based on the end leakage magnetic field of the stator bar. The relationship between strand currents and the leakage magnetic field is derived. By comparing the differences of the end leakage field between the health bar and the fault bar under different short-circuit fault degrees, the functional relationship between the leakage magnetic field signal and the fault currents is established. This detection method is proposed by working on the principle of the Hall-effect sensor. This paper also built a local sample test platform to verify the correctness of the detection method by comparing the experimental results with the simulation results.