The Test And Research On The Performance Of Composite Insulators In Transmission Lines

Insulators is an important part of the transmission lines. In the long term operation of insulators, they will be affected not only by environmental factors such as lightning, pollution, bird damage, ice and snow, high humidity, temperature difference, but also bear electrical effects such as strong electric field, lightning surge current, power frequency arc current role as well as the mechanical effects such as the long-term work heavy load, complex load, conductor galloping and other mechanical force loading. For more than forty years, countries around the world mainly focused on sheds and FRP rod materials, manufacturing processes and test standards of composite insulators and carried out a large amount of basic research. From the perspective of using, how to use it properly and well, how to detect problems during running, these problems lack of sufficient attention. The reason for this phenomenon is that the requirements for composite insulator as a product are relatively uniform and its facing vastly different operating environment. Making service guide or guidance suggestion is very difficult. The main contents of this subject research are divided into three parts:the study of the electrical properties, aging properties and mechanical properties of composite insulators.Firstly, according to the field running characteristics of composite insulators, while meeting the power supply requirements of the reliability of the power grid, this paper designs a new set of on-line insulators hydrophobicity detection method which can be more accurate, convenient and efficient while testing the hydrophobicity of insulator. Secondly, through a variety of tests which meet the national standards, the relevant studies of the electrical performance of composite insulators with different voltage grades, different situations of the pollution and different levels of hydrophobicity have been done. This paper draws the related law of composite insulators with different situations of the pollution and different hydrophobicity to its power frequency wet withstand voltage and pollution flashover voltage and other electrical characteristics. Through a summary and analysis of experimental data, the detection recommendations of the composite insulator which is under actual operation are made. Thirdly, the 5000h multi-factor aging test methods have been improved and they have been used in aging test of composite insulators with different formulas, different state of the contamination, different running time. After summarizing the test results we obtained reliability evaluation method of composite insulators. Finally, systematic experiments were carried out of the mechanical properties of three different connection form which were inner wedge, outer wedge, and clamp composite insulators. The residual mechanical strength of the composite insulators under different voltage grades were studied. It is found that the main factors deciding the mechanical stability and mechanical life of the composite insulators are the connection type of composite insulators. The results show that the clamp composite insulator has the optimal mechanical properties and the inner wedge composite insulator takes second place. The mechanical properties of outer wedge composite insulator are the worst.According to this test and research, comprehensive evaluation has been made on the properties of composite insulators in the transmission line, and on this basis, opinions and suggestions are suggested for the composite insulators application in the transmission line in the future.