Research On On-line Detection Method Of Rated Capacity Of Distribution Transformer Based On Data Fitting

As one of the important equipment in power system,power transformer,especially the small and medium-sized distribution transformer,plays an important role in the economic and stable operation of the whole power system.As one of the key parameters of transformer,rated capacity plays a decisive role in determining the load capacity of transformer and other technical parameters of transformer.At present,the power system tends to be more and more structural integration,and the equipment exists in the system.If the traditional preventive test is still used for power failure detection,it will have a great impact on the whole system,and will also bring great economic losses to users.In order to solve this problem,this paper focuses on the on-line detection technology of distribution transformer,and an on-line detection method based on big data fitting is proposed.At the same time,a comprehensive simulation platform for on-line detection of distribution transformer is built.The main work of this paper is as follows:1.The equivalent circuit model of transformer is established.According to the principle of equivalent circuit,an on-line detection method of transformer short circuit impedance based on data fitting method is proposed.Compared with vector matrix method,it provides a certain reference value for on-line detection of transformer rated capacity.2.Based on the analysis of the principle of transformer loss,the accurate mathematical calculation model of no-load loss of transformer in the process of operation is derived,the fitting calculation formula of no-load loss is determined and applied to the on-line detection of loss,which provides theoretical support for the establishment of the on-line detection simulation system of distribution transformer in this paper.3.The method of multi-element comprehensive detection of rated capacity of distribution transformer is proposed.The rated capacity of the transformer is determined synthetically by using the technical parameters of the transformer and the national standard of the technical parameters of the transformer to ensure the accuracy of the capacity detection.And through all technical parameters,it can also realize the on-line detection of its reactive power loss,which is of great significance to the reactive power compensation and power factor adjustment of distribution transformerin power system.4.To build the on-line detection simulation system of distribution transformer by Matlab / Simulink,including the calculation module of each technology parameter.The load operation of the transformer is simulated,and the output and output voltage and current signals are collected as the data base of the fitting calculation.The iron loss of transformer is analyzed theoretically by using the finite element analysis method,and the iron loss and its components are calculated by building the transformer simulation model and simulating the no-load operation with the aid of external circuit adding excitation,thus the rationality of data fitting calculation is verified.The research content of this paper has a certain reference value for the on-line detection of the rated capacity of distribution transformer,and provides a technical reference for the future engineering application.At last,all the work of this paper is summarized,and the future research direction is prospected.