Winding state evaluation method in the condition of transformer external fault

Abstract

The invention discloses a winding state evaluation method in the condition of a transformer external fault. According to the method, current flows through a transformer winding conducting wire, the magnitude of the electromagnetic force is proportional to the square of passing current, in the condition of high fault current, the electromagnetic force born by a winding is hundred times of that in a normal condition, winding formation happens when winding strength is insufficient, elastic deformation is partly recovered after fault elimination, however the cumulative effect of the winding deformation causes a large accident in the next fault condition. According to the method, the collected current data of two sides of a transformer before and in the fault is used, an appropriate numerical algorithm is utilized, the values of leakage inductance of the transformer before and in the fault are identified and obtained, the deviation of winding leakage inductance in each time in the fault is calculated and analyzed, the tendency chart of the deviation is made with time as a horizontal ordinate, and the shock to the transformer winding by the fault and the state of the winding are evaluated according to the deviation tendency chart.

Description

technical field [0001] The invention belongs to the field of electric equipment monitoring and relates to a method for evaluating the state of a transformer winding under the condition of an external fault. Background technique [0002] As the key equipment in the power transmission of the power system, the power transformer's failure will have a serious impact on the power supply reliability and operation stability of the power system. Statistics on transformer faults over the years show that winding faults account for the vast majority of transformer faults each year, and insufficient short-circuit strength of windings is the main cause of winding faults, and its damage rate accounts for about 60% to 70% of all transformer faults. As a latent accumulation of sub-health state, winding deformation will inevitably bring unpredictable major hidden dangers to the operation of power system due to the development and uncertainty of its faults. [0003] The electromagnetic force ...

AI Technical Summary

Problems solved by technology

[0005] The condition-based maintenance of power equipment that is currently under development only considers the deformation and state of the transformer winding after a fault, and does not take into account the deformation of the winding during the fault process. Therefore, important information such as the deterioration of the winding material and the accumulation of deformation will be missed, and it will be difficult for the transformer to operate. The safety and reliability of the

Although the short-circuit impact and state assessment of transformer windings are of great significance to the safe operation of transformers and the construction of future smart grids, due to the limitations of on-site installation conditions and hardware investment, this technology has not been widely promoted.

Images