An online monitoring method for power transformer operating status under DC bias condition

Abstract

The invention discloses an on-line monitoring method for the operation state of a power transformer under the condition of DC bias, comprising the following steps: collecting vibration signals of the transformer box wall, three-phase voltage signals of the transformer, three-phase current signals of the transformer and neutral point DC current; The transformer vibration clustering model is established based on the K-means clustering analysis method; the measured amplitude of the 100Hz component of the transformer box wall vibration signal is compared with the output of the transformer vibration clustering model. If the relative error between the two is less than a threshold , then it is judged that the transformer is operating normally; if the relative error between the two is greater than or equal to the threshold, it is judged that the transformer is operating abnormally. The method can effectively and highly sensitively monitor the operating state of the transformer under the condition of DC bias on-line, so that effective measures for the DC bias of the transformer can be taken or the transformer can be repaired in time to avoid the occurrence of major faults.

Description

technical field [0001] The invention relates to a signal detection method, in particular to an online monitoring method for the operating state of a power transformer under the condition of DC bias. Background technique [0002] Under the national strategic policy of "West-to-East Power Transmission, North-South Mutual Supply", High Voltage Direct Current (HVDC) has played an important role in the long-distance power transmission of my country's West-East Power Transmission due to its advantages of large transmission capacity and long transmission distance. It has played a very important role and has been widely used. [0003] The operation modes of the DC transmission system mainly include three types: unipolar, bipolar and homopolar. Most of the DC transmission systems in my country are bipolar neutral point grounding systems. However, when HVDC power transmission adopts single-pole ground loop operation mode or bipolar unbalanced operation mode, a current of up to several...

AI Technical Summary

Problems solved by technology

Local overheating will age the insulation and decompose the transformer oil, which will affect the life of the transformer and have a serious impact on the normal operation of the transformer

In addition, the DC bias makes the transformer a harmonic source in the power system, which not only increases the reactive power consumption of the transformer, but also may cause the protection relay to malfunction, so how to accurately monitor the working state of the transformer under the condition of DC bias Monitoring is a key link in power delivery

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