Transformer Winding Deformation Detection and Modeling Based on Frequency Response Method

Power transformer is one of the key equipment of the power system, and its reliable operation is an important factor for the safety of the whole power grid and even national power. With the increasing scale of the power grid, the probability of transformer failure due to winding deformation is on the rise. When using online frequency response method to detect winding deformation, it needs to be verified with simulation, the experiment provides a scientific basis for simulation, and simulation verifies the correctness of the experimental method. At present, the field experiment affects the accuracy of winding deformation detection mainly because of the signal injection and extraction, power system noise and the analysis of the experimental results; in the simulation analysis, the error mainly exists in the establishment of the transformer winding model, and the frequency response curve obtained from the simulation of different precision models is not consistent. This paper summarizes the research results in recent years from several aspects such as signal injection and measurement methods and different winding modelling structures. Firstly, the advantages and disadvantages of the frequency response method, which is the most widely used method in the detection of winding deformation, are compared between offline and online, and several new detection methods are analyzed; afterwards, several measurement techniques are introduced according to the signal injection and extraction problems encountered in the experiments; finally, the method of constructing the winding model of transformers is proposed, and there is an urgent need to obtain a more accurate winding model. Comprehensively, the above three aspects of improving the accuracy of winding deformation detection are outlined, and the next research direction will be gradually transferred to the construction of a digital twin model of winding wide-band electromagnetic characteristics, revealing the precise quantitative mapping mathematical equation from the winding structure to the electromagnetic characteristics of its ports, and promoting the development of transformer digitalization.