Test method for evaluating oxidation stability of transformer oil under high-voltage alternating current or direct current field

Abstract

The invention relates to a test method for evaluating oxidation stability of transformer oil under a high-voltage alternating current (AC) or direct current (DC) field, and the method can be applied in evaluation and actual measurement of transformer oil oxidation stability. The method comprises: under a high-temperature and high-voltage AC or AC field and in the presence of a metal catalyst, introducing air or oxygen for accelerated oxidation of transformer oil, using an oil dielectric loss factor measuring electrode cup built in an analog device for on-line monitoring of the dielectric loss factor change, and taking the time needed for the monitored dielectric loss factor to reach the specified value 0.02 as an index for investigating the oxidation stability of transformer oil. The method provided in the invention can evaluate the oxidation stability of transformer oil under a high-temperature and high-voltage AC or AC field and with the presence of oxygen as well as a metal catalyst.

Description

technical field [0001] The invention relates to the technical field of power grid transmission and transformation, in particular to transformer oil used as an insulating material in a transformer, and is a test method for evaluating the oxidation stability of transformer oil under a high-voltage AC or DC electric field. It is mainly used to evaluate the oxidation stability of transformer oil used in electrical equipment such as transformers, converter transformers, transformers, and reactors. Background technique [0002] In recent years, with the implementation of the West-to-East Power Transmission Project, my country's electric power industry has entered the development period of large power grids and UHV power grids. 750kV and 1000kV UHV AC power transmission projects, ±500kV HVDC, ±660kV and ±800kV have been built successively. UHV DC transmission project. Transformer is an extremely important power transmission and transformation equipment in power transmission enginee...

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Problems solved by technology

[0005] In the 1970s, my country's electric power department designed a set of simulation equipment and test methods for evaluating the anti-oxidation stability of transformer oil under the condition of AC electric field, but the equipment has the following defects: First, it can only evaluate the stability of transformer oil under AC electric field. The anti-oxidation performance cannot be evaluated under a DC electric field; the second is that the electric field strength is fixed and cannot be adjusted and the electric field strength is small; the third is that there is no distribution pipe for the oxygen introduced; the fourth is that the water-soluble acid of the oxidized transformer oil reaches 0.014mgKOH / g Compared with the operating condition of transformer oil as insulating oil, it is unscientific to adopt this project as "oxidation life"; fifthly, it is limited by the technical level at that time, and the level of self-control is low

However, there are defects in this equipment: first, there is no distribution pipe for the oxygen that is introduced, resulting in uneven distribution of oxygen in the test oil samples, and the uniform oxidation of all test oil samples cannot be achieved; second, the acid value of the oxidized transformer oil reaches the specified index Compared with the operating condition of transformer oil as insulating oil, it is unscientific to adopt this project, and it cannot directly reflect the decline trend and degree of transformer oil insulation performance; third, the measurement process cannot realize automatic measurement and Automatic Data Collection

[0007] Insufficiency of the current evaluation method for the oxidation stability of transformer oil

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