Identification of PQ disturbances based on change in audible noise of three phase IM

In India the technological developments in the last two decades have led to an ever-increasing use of electronic devices. Also, the Indian power sector is presently facing the serious power crisis. Therefore, quality of available power is emerging as a major problem, especially in rural area, where three phase Induction Motor is widely used by farmers and they encounter losses, due to poor PQ as most of them are not aware about PQ problem, also are not educated enough to understand the sophisticated measurement and analysis techniques. Hence, they must be acquainted with PQ problem by using the technique they can understand. The aim of this paper is to put the most common PQ disturbances in the way, that, a layman can understand. For any given IM the noise emitted by it under normal supply conditions and under the influences of PQ disturbances is distinctly different. Also, the change in noise depends upon the type of PQ disturbance and its severity. A laboratory experiment is setup for investigating, three different types of PQ disturbances, namely, sustained low voltage, supply-magnitude unbalance and harmonic distortions. A low cost and efficient method for data acquisition consists of a microphone to detect noise and PC sound card for A/D conversion. Data acquisition and signal de-noising is done in MATLAB. The results obtained in each case are presented.