New Measurement Method of Viscosity, Density, and Dielectric Constant of Transformer Oil Based on Quartz Tuning Fork

Abstract

Transformer oil is a liquid insulating material used in ultra-high voltage power equipment such as oil-immersed transformers and reactors. Online monitoring of its characteristics helps to maintain the status of power equipment. Aiming at the problem of single detection parameter in traditional methods, a new detection method for density, viscosity and dielectric constant based on quartz tuning fork is proposed in this paper. Firstly, by analyzing the working mechanism of the quartz tuning fork, the sensor detection model and parameter extraction method in air are constructed based on the equivalent circuit model of the Butterworth-Van Dyke model. Then, the working mechanism of the density, viscosity and dielectric constant of the transformer oil is analyzed, and the method of parameter extraction of sensor in standard oil sample and measurement model of sensor in oil sample to be measured are obtained. Finally, an experimental platform is built to verify the above conclusions. The results show that the quartz tuning fork detection model has good repeatability, the measurement errors of density, viscosity and dielectric constant are 2.52%, 6.53% and 3.36%, respectively, which meet the online monitoring accuracy requirements. The detection technology of transformer viscosity, density and dielectric constant based on quartz tuning fork realizes the simultaneous detection of three parameters in the same method, which meets the requirements of miniaturization, diversification and real-time detection of power parameters under the condition maintenance system, and also provides a new application scenario for tuning fork quartz crystal oscillators.

Design of a Transformer Oil Viscosity, Density, and Dielectric Constant Simultaneous Measurement System Based on a Quartz Tuning Fork

“…A transformer oil sample 1 with known characteristic parameters is selected. Its conductivity spectrum is measured, and calibration at the series resonance point is performed to obtain M, N, and dC P /dε constants as shown in Equations ( 4)-( 6) [22].…”

“…However, the measurement of dielectric constant is also critical to the safe operation of transformers, so the development of a device that can simultaneously measure the three parameters of a transformer is vital. The feasibility of a quartz tuning fork three-parameter measurement was investigated by this project team in an earlier study [22]. Building on this foundation, this paper designs a measurement system for simultaneous measurement of three parameters of transformer oil density, viscosity, and dielectric constant, which provides a real-time, low error, and miniaturized solution for monitoring transformer oil characteristics.…”