Perfluoro ketone environment-friendly alternative gas thermodynamics simulation method

Abstract

The invention belongs to the field of a mechanism analysis on overheat faults of a gas-insulated medium in gas-insulated electric equipment and specifically relates to a perfluoro ketone environment-friendly alternative gas thermodynamics simulation method. A simulation study is performed on a decomposition product in a condition of an overheat fault of perfluoro ketone environmentally-friendly insulated gas, and preliminary construction of a molecular structure, functional selection of a DFT (density functional theory), selection of basis sets, optimization of the molecular structure, calculation of bond energy and calculation of reaction heat. The simulation method has the following advantages: 1, as the insulated gas cannot be completely purified in an actual experiment condition, the mechanism analysis is performed on a decomposition approach of the perfluoro ketone environmentally-friendly insulated gas when in overheating by adopting reaction thermodynamics according to the method, so as to obtain overheat decomposition products of perfluoro ketone CnF2nO gas molecules at different temperatures; 2, the energy conditions of the perfluoro ketone CnF2nO gas molecules and decomposition products thereof in a heated condition can be analyzed from a micro-level.

Description

technical field [0001] The invention belongs to the field of overheating failure mechanism analysis of a gas insulating medium in gas-insulated electrical equipment, and in particular relates to a thermodynamic simulation method for perfluoroketone environment-friendly alternative gas. Background technique [0002] Sulfur hexafluoride (SF 6 ) Because of its outstanding insulation performance and arc extinguishing characteristics, it is widely used in metal-enclosed switchgear (Gas Insulated Switchgear, GIS), and the gas consumption of high-voltage switchgear accounts for about SF 6 More than 80% of the gas consumption, medium voltage switchgear gas consumption accounts for about 10%. With the continuous development of the power industry, the installation of GIS equipment in the power grid system is increasing, SF 6 usage is also increasing rapidly, while SF 6 The process of commissioning and overhaul of gas-insulated equipment, as well as the leakage and recovery of gas w...

AI Technical Summary

Problems solved by technology

Although perfluoroketone insulating gases have excellent insulation properties and environmental indicators, they cannot be used alone due to their liquefaction temperatures as high as 26.9°C and 49.2°C, and buffer gases with low liquefaction temperatures such as CO 2 , N 2 Equal mixing makes the liquefaction temperature lower to prevent its liquefaction

However, the effective contact area of ​​bus bars and connectors inside C-GIS is often reduced due to vibration, corrosion, etc., resulting in poor contact of the connectors, or when the conductor is overloaded, the thermal stability of the defective parts will be destroyed, making the gas insulation medium The temperature continues to rise, causing the occurrence of a partial overthermal fault (Partial Overthermal Fault, POF)

Perfluoroketone environment-friendly alternative gas C n f 2n O as a gas insulating medium, when POF appears inside C-GIS, it may lead to a lower volume fraction of C in the mixed gas of perfluoroketones. n f 2n O is pyrolyzed, and the decomposition products produced therein may also cause corrosion to the surface of the internal metal parts of C-GIS, etc., and cause harm to the insulation performance

However, currently for C n f 2n O's research mainly has alternatives to SF in terms of environmental indicators and electric strength 6 The possibility of gas, as well as its decomposition characteristics and thermal stability when POF appears in C-GIS are not yet clear, and these contents are one of the key issues in the development and research of perfluoroketone environment-friendly insulating gases in the field of power systems one

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