Analysis of SF6 and CF4 consumption for refueling high-voltage switching equipment

Abstract

The article describes to eliminate possible errors in the supply of cylinders with sulfur hexafluoride and cylinders with carbon tetrafluoride to high-voltage substations for refueling switching devices such as high-voltage switches, voltage transformers, etc. Conduct an analysis of possible erroneous supplies of the two above-mentioned gases at the substation. Make an analysis of possible residuals (or shortfalls) of gas cylinders after refilling. Make an assumption about the reasons for the appearance of possible residues. Give recommendations for overcoming possible problems. Make the appropriate calculations. Propose a formula (table) for recalculating the consumption of both types of gases. Make a table for calculating the actual values of the number of supplied cylinders, related to the discreteness of the volumes of the cylinders and the switching devices themselves. Draw appropriate conclusions and make recommendations. To achieve this goal, a method was used to calculate the state of an ideal gas using software for working with spreadsheets. The article reflects the relevance of the topic and discusses the features of refueling high-voltage SF6 equipment in various climatic conditions (below minus 40-49°F). An analysis of typical ratings of high-voltage switches used at highvoltage substations was carried out. A graph is presented for converting the molar fraction (contributing to pressure) of gases into the mass fraction. A sample calculation of the number of cylinders is presented for two commonly encountered volumes of switching devices and fortyliter gas cylinders for several standard cylinder filling ratios. Presumptive conclusions are presented regarding the assessment of real errors when sending gas cylinders for refilling switching devices. The article offers an understanding of the sequence of problems associated with incorrect calculations and a complete methodology for calculating the correct volumes (mass) of gas depending on the actual types of devices used, depending on the volume of supplies pieces of equipment.