Piezoelectric Transformer Based Disturbance Monitoring Methodology for High-Voltage Power Supply Lines

We present a novel microsystem methodology to detect voltage and current disturbances in high power distribution lines. Our system employs a custom designed piezoelectric transformer operating at 50/60 Hz, as an alternative to the bulky electromagnetic transformer, to detect disturbances up to few kilohertz. In the frequency range of 10 Hz to 250 Hz, the piezotransformer steps down the 10-150 V input voltage with a linearity of ±1%. This stepped down piezo output is treated with a signal processing system designed based on frequency composition of the piezo signal, to generate a digital output. A 7-bit digital output from this system reports various types of line disturbances within 3 ms of occurrence. We present details of the proposed system, supported both by numerical simulations and experimental results.