A Method for Determining the Withstand Voltage Value of Factory Test of Converter Transformer After Overhaul

Abstract

The invention discloses a method for determining the withstand voltage value of a factory test after a converter transformer is overhauled, and relates to the technical field of high-voltage electrical equipment detection. Sampling is carried out to measure the viscosity-average polymerization degree of several groups of cellulose electrical insulation materials for insulating paper samples. Based on the relationship between the degree of polymerization of insulating paper and the factory test voltage value after maintenance, determine the withstand voltage value of the converter transformer factory test after maintenance . This method determines the withstand voltage value of the factory test after the overhaul of the converter transformer as accurately as possible, can test the quality of the converter transformer overhaul to the greatest extent, ensures that the insulation of the converter transformer meets the requirements for operation and use, and avoids the excessive test voltage value from affecting the existing transformer. Irreversible damage to the internal insulation of the converter transformer that has been used for a long time can also prevent the low test voltage value from being able to fully and effectively detect the converter transformer that has just been put into operation.

Description

technical field [0001] The invention relates to the technical field of high-voltage electrical equipment detection, in particular to a method for determining a withstand voltage value of a factory test after a converter transformer is overhauled. Background technique [0002] Converter transformers need to be overhauled after a major fault occurs. After the overhaul is completed, a factory test is required. The factory test is the most important means to check the quality of converter transformer maintenance, and it is also the most stringent inspection level to judge whether it can be put into operation. After the converter transformer is overhauled, its structure and electrical performance will decline to a certain extent compared with the newly built converter transformer. The method and judgment standard are the same as those of the factory test of new converters, but when it comes to withstand voltage high-voltage tests, it is generally handled in the following ways: su...

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Problems solved by technology

[0003] The withstand voltage value of the above processing method is low to protect the internal insulation of the converter. This has the following problems in actual operation: the new converter is tested at 100% of the test voltage value (that is, the standard specified value). If 80% of the test voltage value is used after the converter substation is overhauled after the completion of the fault under different operating years and different insulation materials, the factory test has a very limited effect on the assessment of the internal insulation, that is, it cannot fully detect the weak links of the internal insulation. If it is more extreme, when the converter is put into operation, the maintenance will be carried out soon, and the internal insulation materials are in good condition. After the maintenance is completed, there is not much difference from the new converter. However, if the converter transformer fails after nearly 20 years of operation, it is intuitively reasonable to set the test voltage at 80% after overhaul, because the converter transformer insulation material, etc. The remaining life is in the final stage, the test voltage value can fully ensure that the insulating material will not be damaged by the test voltage, and can pass the on-site handover test smoothly

[0004] Therefore, in the prior art, it is impossible to effectively determine the withstand voltage value of the factory test after the converter transformer is overhauled

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