Power transformer DC magnetic bias state detection method based on noise method

Abstract

The invention provides a power transformer DC magnetic bias state detection method based on a noise method. The state detection method comprises transformer noise sound pressure level and sound power level measurement and noise spectrum analysis method. According to the method, magnetic bias condition of the DC invaded into a transformer and the magnetic bias state of the transformer are determined according to the transformer noise sound pressure level and sound power level added values and change of the noise spectrum. The detection method is simple, practical, energy saving and highly-efficient, can be jointly used with other electric performance test methods being combined, can also be used alone, and can carry out detection and analysis on the DC magnetic bias state of the transformer to guarantee the transformer to run safely and reliably in the DC magnetic bias state. The detection method is suitable for three-phase five-column, single-phase three-column and single-phase four-column iron core type transformers, and is not suitable for a three-phase three-column iron core type transformer.

Description

technical field [0001] The invention relates to the technical field of power transformers, in particular to a detection method for a DC bias state of a power transformer based on a noise method. Background technique [0002] Equipment failures in the DC transmission system, routine preventive maintenance, and single-pole commissioning and commissioning in the initial stage of converter station construction often lead to the operation of the DC transmission system in the single-pole ground loop mode or the double-pole unbalanced mode. When the DC current flows into the AC transformer with the neutral point grounded through the ground pole, it will cause DC bias, DC magnetic potential or DC magnetic flux to cause a series of electromagnetic effects of the transformer, including magnetic saturation of the iron core half cycle, loss, temperature rise increase, If the saturation degree of the iron core is high, it may cause the increase of flux leakage to cause local overheating, ...

AI Technical Summary

Problems solved by technology

[0002] Equipment failures in the DC transmission system, routine preventive maintenance, and single-pole commissioning and commissioning at the initial stage of the construction of the converter station often lead to the operation of the DC transmission system in the single-pole ground loop mode or the bipolar unbalanced mode

When the DC current flows into the AC transformer with the neutral point grounded through the ground pole, it will cause DC bias, DC magnetic potential or DC magnetic flux to cause a series of electromagnetic effects of the transformer, including magnetic saturation of the iron core half cycle, loss, temperature rise increase, If the saturation degree of the iron core is high, it may cause the increase of flux leakage to cause local overheating, aggravate vibration, and increase operating noise. The harmonics generated by it will also cause system voltage waveform distortion and relay protection malfunction, etc., which will affect the safe operation of the transformer, and This situation is becoming more and more serious with the continuous increase of ultra-high voltage direct current transmission lines in my country.

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