Analysis of the features of the shielding system of polymer insulation structures of high voltage electrical equipment

Abstract

In the article, the authors analysed the existing shielding systems of insulating structures of high-voltage devices together with electrodes under high potential. At the same time, the possibilities of using toroidal screens of various designs and the conditions of their installation in gas-filled equipment structures (gas-filled current and voltage measuring transformers, arresters, etc.) using polymer insulating materials are considered. Based on the analysis of literary sources, the most effective method of estimating the electric load parameters for determining the electric field strength distribution along the continuous insulating structure of gas-filled high-voltage devices with axial symmetry is proposed. This design is a support-insulating shell filled with SF6 as an internal insulating medium. Methodical materials are recommended that allow you to estimate the electrical load parameters (voltage and field strength) depending on the design features of the device and the shielding system used to level the electric field. Based on them, it is possible to evaluate the effectiveness of the calculation coefficients of the shielding system of gas-filled high-voltage equipment in the design process and during the improvement of individual design solutions. The results of the analytical evaluation by such methods are in good agreement with the data of experimental studies and statistical information obtained as a result of monitoring the work of insulating structures, taking into account real operating conditions and the influence of external factors. The introduction of the obtained materials allows you to take into account the influence of external factors and operational characteristics inherent in measuring transformers and overvoltage limiters. To explain the results of the analysis of methodical materials carried out in the article, as an example, the results of calculations of the support-insulation shell of the gas-filled current transformer of the TOG series, which was the most affected during operation, are given. in adverse conditions, given under such conditions as external pollution, humidity and their combination, as well as under conditions of overvoltage of various origins, etc. On the basis of the presented materials, it is possible to more accurately determine the effectiveness of various screenings. system, as well as how to predict the field strength distribution parameters under the influence of the shielding system, taking into account its design features. In addition, on the basis of the conclusions formed in the work, it is possible to plan and conduct an additional series of calculations and experimental tests taking into account the features of specific structures. Thus, the obtained results can be used to evaluate the external insulation parameters of both gas-filled measuring transformers and similar high-voltage equipment of distribution devices and transformer substations.