A method for on-line monitoring of transformer internal faults

Abstract

The present invention relates to a kind of transformer internal fault on-line monitoring method, it is characterized in that, specifically comprises the following steps: 1) establishes T-type equivalent circuit model according to transformer circuit structure; 2) structure target function J, see following formula (I), use To solve the high voltage side resistance R 1 , High voltage side leakage resistance X 1 , Low voltage side resistance reduced value R 2 ', Low-voltage side leakage reactance reduced value X 2 ', excitation resistance R m , Exciting reactance X m , 3) In the normal condition of the transformer, the above formula J is used as the objective function, and the optimization algorithm is selected for optimization calculation, and R 1 、X 1 , R 2 ', X 2 ', R m 、X m 4) online monitoring of the transformer, 5) comparison to determine the type of fault. The online transformer internal fault monitoring method of the present invention judges transformer equivalent circuit parameters such as winding resistance, leakage reactance and equivalent excitation branch impedance through online calculation and identification, and can monitor windings and iron cores in real time to realize different internal fault detection Classified monitoring, with high sensitivity to minor core faults or minor turn-to-turn short circuits.

Description

technical field [0001] The invention belongs to the technical field of transformer operation monitoring, and in particular relates to an online monitoring method for transformer internal faults. Background technique [0002] The operation status of the transformer directly affects the safety and stability of the power equipment and even the entire power grid. In the prior art, methods for detecting internal faults of transformers based on transformer equivalent circuit parameters mainly include short-circuit impedance method and leakage inductance method, which can detect whether there is deformation or short circuit in the winding. The short-circuit impedance of the transformer refers to the equivalent impedance of the transformer when the load impedance is zero and the load current is the rated value, and the leakage inductance is the imaginary part of the short-circuit impedance, that is, the inductance corresponding to the short-circuit reactance. After the transformer ...

AI Technical Summary

Problems solved by technology

However, although the leakage inductance method can reflect the winding deformation and inter-turn short circuit online, it cannot distinguish the two; and when there is a slight inter-turn short circuit, the change of the leakage inductance is not obvious due to the small number of shorted turns , so the method is not sensitive enough for this case

[0005] In addition, the above-mentioned short-circuit impedance method and leakage inductance method can only monitor the winding, and cannot reflect the fault of the iron core.

Images