Development of multi-parameter online monitoring equipment for EHV transformer bushing

• Published in: IET science, measurement & technology measurement & technology, 2020-01, Vol.14 (1), p.98-103
• Main Authors: Zhang, Lu, Sun, Lei, Wu, Jingfeng, Han, Yanhua, Wang, Sen, Yang, Chuankai, Shen, Wei, Guo, Can
• Format: Article
• Language: English
• Subjects: bushing oil; bushings; chemical sensors; chemical variables measurement; control cabinet; data analysis; dissolved hydrogen; EHV transformer bushing; fault diagnosis; hydrogen measurement range; hydrogen sensor; low power consumption; oil pressure; oil temperature; oil‐less equipment; oil–gas separation membrane; online multiparameter monitoring equipment; palladium alloy film technology; palladium alloys; power grid accidents; power transformer insulation; pressure 0.0 MPa to 1.0 MPa; pressure 0.1 kPa; pressure measurement; pressure measurement range; pressure monitoring; pressure sensors; protective film; Research Article; Si3N4; signal acquisition; silicon compounds; temperature measurement; temperature measurement range; temperature sensors; temperature ‐40.0 degC to 105.0 degC; thin film sensors; transformer bushing faults; transformer oil; voltage 330.0 kV
• ISSN: 1751-8822; 1751-8830; 1751-8830
• DOI: 10.1049/iet-smt.2019.0262

To diagnose the running state of bushing and avoid serious power grid accidents, online multi-parameter monitoring equipment for dissolved hydrogen, oil pressure and temperature in bushing oil was developed. The equipment includes three units: signal acquisition, control cabinet and data analysis. A new hydrogen sensor without oil–gas separation membrane and based on palladium alloy film technology was developed. A three-in-one sensor for hydrogen, oil temperature and pressure monitoring has been developed, which has the advantages of miniaturisation, lightweight and easy installation. Test results show the hydrogen measurement range of the sensor is 0–5000 ppm, and the accuracy can reach 10% or 15 ppm (with larger values). The pressure measurement range is 0–1.0 MPa, the resolution is 0.1 kPa, and the accuracy can reach 0.25 grade. The temperature measurement range is −40 to 105°C, and the accuracy is ±1°C. The measurement performance of the device fully meets the requirement of online monitoring of transformer bushing. The equipment has been put into operation in a 330 kV substation, which can monitor the bushing status online and help eliminate the early latent fault of bushing in the weak budding state.