The Research Of Data Synchronization And Heat Calculation In Electronic Transformer

Electronic transformer and merging unit(MU) are the key equipments in process layer of intelligent substation, as the intermediate link of intelligent primary equipment and secondary protection, measurement, metering device, merging unit needs to receive signals from multiple transformers, in order to meet the needs of secondary equipments, the data synchronization problem among multiple signals must be considered. In this paper, the interpolation method is used to realize data synchronization of electronic transformer, using MATLAB software to write the interpolation algorithm program on the basis of the deep understanding of linear interpolation, quadratic interpolation, piecewise cubic Hermite interpolation, cubic spline interpolation and B-spline interpolation algorithm, making periodic sampling for a given steady state and transient current signal, calculating the sampling value error. The interpolation FFT algorithm program is also written to use the "new sampling sequence" to calculate amplitude and phase of every harmonic, and compared with the real value, calculating the amplitude and phase error.Through numerical simulation and calculation, the comparison of different interpolation algorithms is as follows: the error of linear interpolation is the biggest;Quadratic interpolation algorithm can improve the calculation accuracy, but the improvement is not obvious; piecewise cubic Hermite interpolation further improves the calculation accuracy, but the calculation error of higher harmonic is still large; the calculation accuracy of cubic spline interpolation is greatly enhanced, and the interpolation node has second order smoothness, but the function expression in each cluster interval is different, which is not conducive to popularization and application;Furth B-spline interpolation uses the form of the basis function, the expression is simple, and the calculation precision is also higher than the cubic spline interpolation.On the other hand, the variation of temperature may influence the measuring accuracy of electronic transformer. For the electronic transformer which is arranged in the open air, the temperature will rise because of factors such as resistance loss, sunexposure, etc, even exceeds the permitted temperature rise in practical operation,which will influence its working performance. To analyze its loss and heat problem accurately and ensure the safety and reliability of its operation, a fluid-thermal coupled solution model was established through the FLOTRAN CFD module in ANSYS software by using finite element method, which calculated and analyzed the distribution regularities of the fluid field and temperature field in consideration of factors such as sun exposure, shell circulation current, gas flow, gravity and the resistivity temperature effect.The calculation results show that for the given transformer model, thermal field distribution has the geometric regularity of basic symmetry on both sides and upper temperature higher than the lower temperature, the highest temperature appears on the top of the conductor and the lowest temperature appeared directly below the conductor. Because of the existence of shell circulation current, the heating problem is more serious, and the increase of the pressure is beneficial to the heat dissipation of GIS electronic transformer. The conclusions have some reference value for the heat dissipation design of electronic transformer.