Design of Intelligent Sensing System for Insulation State of Power Transformer Based on Moisture Content

The small amount of moisture in transformer oil will reduce its insulation performance and cause major accidents such as insulation breakdown of the transformer. Traditional methods for measuring the content of moisture in transformer oil have disadvantages such as poor real-time performance and low accuracy. This paper proposes a method to indirectly measure the content of moisture in oil by measuring the dielectric constant of the dielectric layer of a capacitive sensor on-line. A capacitive sensor with multi-interdigital electrode structure on the same plane is designed. The influence of plate width and plate spacing on sensitivity is analyzed by finite element method, and the dielectric layer thickness is determined by electric field simulation to determine the optimal structural parameters of the sensor.Use the Pcap02 chip to measure the capacitance, and upload the data to the cloud platform through the microprocessor and narrowband Internet of things technology. Experimental verification shows that the system has high measurement accuracy, good stability, and meets the requirements of on-site operation, providing a reliable basis for transformer maintenance personnel to analyze its operating status.