Considering the long length of gas-insulated transmission lines (GILs), novel methods are required to alleviate the impacts of axial diffusion on decomposition products' monitoring. The diffusion process of two typical decomposition products, SO₂ and SO₂F₂, was studied. During the diffusion experiments, SO₂ and SO₂F₂ were generated by partial discharges. Based on Fick’s law, an axial diffusion model of SO₂ and SO₂F₂ was proposed. By combining the experiment and simulation results, it was found that the diffusion coefficient of SO₂ was greater than that of SO₂F₂. In addition, the concentration variation at different positions would experience some delay and decay in axial direction. The delay and decay were inversely related to the diffusion coefficient and increased with prolongation of the distance. Based on the diffusion characteristics determined, methods for optimising the monitoring positions, correcting concentration, and using the concentration ratio and generation rate were proposed to alleviate the impacts of diffusion. The methods could allow the decomposition products to be monitored in 1 month and reduce the monitoring error to 10% or less. The diffusion model and the methods could be useful for monitoring decomposition products in GILs.

中文翻译：

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气体绝缘输电线路中减轻轴向扩散对分解产物监测影响的方法

考虑到气体绝缘传输线 (GIL) 的长度较长，需要新的方法来减轻轴向扩散对分解产物监测的影响。研究了两种典型分解产物SO ₂和SO ₂ F ₂的扩散过程。在扩散实验中，SO ₂和 SO ₂ F ₂由局部放电产生。基于菲克定律，提出了SO ₂和SO ₂ F ₂的轴向扩散模型。结合实验和模拟结果，发现SO 2 的扩散系数大于SO ₂的_{扩散系数。}F ₂。此外，不同位置的浓度变化在轴向上会出现一定的延迟和衰减。延迟和衰减与扩散系数成反比，并随着距离的延长而增加。根据确定的扩散特性，提出了优化监测位置、校正浓度、利用浓度比和生成速率的方法，以减轻扩散的影响。该方法可以在1个月内对分解产物进行监测，并将监测误差降低到10%以下。扩散模型和方法可用于监测 GIL 中的分解产物。