Detection And Evaluation Of Dynamic Additional Component Of Electronic Transformer

At present,the smart substation in our country is in full construction period.Electronic transformer as an indispensable smart high voltage equipment in smart substation process layer,with smart substation have been put into operation,the electronic transformer has changed from theoretical research to practical application.Although there are many advantages of the electronic transformer compared with the traditional electromagnetic transformer,there are still some problems in the practical application.This paper takes Sichuan malfunction of a smart substation event as an example,analyzing the malfunction accident due to the dynamic behavior of electronic transformer,and researching the dynamic additional component of electronic transformer in power transmission no-load closing.Considering the power system malfunction of such event is can't be reproduced online,so how to detect dynamic component offline,and evaluate its impact on the protection of the relay,avoid malfunction happening again,also became a problem urgently to be solved in this paper.Based on the above purpose,the main work of this paper is as follows:This paper first introduces the hardware and software integration scheme commonly used in electronic transformers,and compares the integral effects of the two schemes of the two integral schemes;subsequently,analyzes the causes and affecting factors of the dynamic component,pointed out that the traveling wave process of the transmission line is the reason for the formation of the dynamic additional component,the sampling rate of the acquisition card and the differential characteristic of the Rogowski coil are the influencing factors of the dynamic additional component.Then,the electromagnetic transient model including the transmission system and Rogowski coil is established.Simulation analysis of dynamic response of the Rogowski coil to various electromagnetic transient phenomena;the simulation results of the different transmission line lengths and different closing phase angles are given;the free oscillation of the Rogowski coil under traveling wave excitation is studied and verified by simulation and experiment.In order to detect the dynamic additional components offline,and avoid the generation of large current and high voltage signal,this paper presents the detection method of Rogowski coil sensor head simulation and object detection,electromagnetic transient simulation and analog reconstruction.And presents the key technology of interval output full scan,upper computer control self-zeroing.Through the dynamic response test,successfully detected the dynamic additional component.The results of the test are compared with the results of the case recording,the waveform is similar,the peak is close and the coincidence degree is high,thus verifying the correctness of the detection method.Finally,the influence of dynamic additional components on the protection was evaluated by the differential protection test of A and B two manufacturers,it will cause malfunction of protection.At the same time,according to the protection test results,the dynamic performance of the electronic transformer is judged.