Analytical testing

Dissolved gas in the oil can diagnose the operating condition of the transformer under the active state, which has been widely used worldwide。

When abnormal signs such as overheating, corona or discharge occur inside the transformer during operation, the insulating oil will be decomposed into small molecular gases (such as H2, CO, CH4, C2H6, C2H4, C2H2, etc.), so these gas molecules are analyzed The level of concentration and the mutual proportion distribution can diagnose the cause of abnormality and whether it needs to be dealt with professional advice。

The gas analysis and detection method in transformer oil is carried out in accordance with ASTM D3612 standard, analyzing the concentration of nine component items, including O2 (oxygen), N2 (nitrogen), H2 (hydrogen), CO (carbon monoxide), CO2 (carbon dioxide), CH4 (methane) , C2H6 (ethane), C2H4 (ethylene), C2H2 (acetylene), etc.。

The analysis of furfural compounds in oil can diagnose whether the insulation paper inside the transformer is deteriorated in the live state, and can accurately estimate the degree of polymerization of the insulation paper, and evaluate the remaining life of the transformer. It is used internationally to evaluate the quality of the insulation paper in the running transformer Important methods and indicators。

When the insulation paper part of the transformer is in operation, such as local overheating, sudden electrical stress, high water content, high oxygen content and other abnormal signs, the insulation paper will gradually decompose into five furfural decomposition compounds (such as: 2-furaldehyde) , 2-furfural alcohol, 5-hydroxymethyl-2-furaldehyde, 2-acetfuran, 5-methyl-2-furaldehyde, etc.), by analyzing the concentration of these individual furfural decomposition products, it can be effective and accurate Assess the degree of polymerization of the current solid insulating paper, and grasp the condition of the insulating paper and the evaluation of the remaining life. The analysis and detection method of furfural in transformer oil is carried out in accordance with ASTM D5837 standard. The concentration of five compounds is analyzed, including 2-furfural (2FAL), 2-furfural alcohol (2FOL), 5-hydroxymethyl-2-furfural (5H2F), 2 -Acefuran (2ACF), 5-methyl-2-furaldehyde (5M2F), etc.。

Transformers will cause failures due to the presence of corrosive sulfur in the insulating oil. Copper sulfide will be produced after corrosive sulfur erodes the copper. The copper sulfide will be transferred to the insulating paper, degrading the dielectric strength and causing serious transformer failures. The purpose of this analysis is to provide a method for identifying and evaluating the corrosive sulfur compounds in the insulating oil of the transformer in operation, so as to maintain the normal operation of the transformer。

The analysis of antioxidant content in transformer oil is performed using FTIR and in accordance with ASTM D2668 standard method. When the concentration of antioxidant in transformer oil is less than 0.1%, it is recommended to add antioxidant again to ensure that the insulating oil in the transformer will not accelerate aging。