Research On High Precision Digital Integrator And Anti-electromagnetic Interference Technology Of Rogowski Coil Electronic Current Transformer

The current transformer is an important current data support device in the power system.The accuracy and reliability of its operation will directly affect the.stable operation of the system measurement system and the relay protection system.Compared with traditional electromagnetic current transformers,electronic current transformers have many forward-looking advantages such as large response range,good transient steady-state performance,easy digital measurement,and easy interface with the same protection system.Need to make it a mainstream current measurement device in smart substations.In recent years,the related technology of Rogowski coil electronic current transformer has been developed rapidly.However,there are still deficiencies in the research of design and operational reliability,so that some problems are likely to occur in actual operation.For example,there is currently a problem of unstable long-term measurement accuracy in optoelectronic current transformers.In addition,reliability failures related to frequent electromagnetic interference are prone to occur in lightning strikes and high-voltage switch operations.In view of the measurement accuracy problems of digital integrator in Rogowski coil electronic current transformer,this paper first makes a comparative analysis and Research on the accuracy of traditional numerical integration algorithms such as trapezoid,rectangle and Simpson.On this basis,a new algorithm based on Al-Alaoui algorithm is proposed,which is optimized in sampling frequency,delay factor and attenuation factor the normalization accuracy of the optimization algorithm is calculated in MATLAB.The results show that the absolute errors of amplitude and phase angle response of the optimized algorithm are greatly reduced.Aiming at the problem of strong conducted electromagnetic interference in the operation of GIS isolation switch and lightning current action of Rogowski coil electronic current transformer,this paper first mathematically modeled Rogowski coil and built its simulation model in ATP-EMTP.The characteristics of the interference signal generated by the conducted electromagnetic interference on the Rogowski coil in the system during the operation of the GIS disconnector and the lightning current in the substation are further studied.According to its high frequency and high amplitude characteristics,the output port of the Rogowski coil is proposed.An electromagnetic protection scheme for resisting strong conduction electromagnetic interference,such as a charge drain channel,is added.The simulation results of the test model built in the software ATP-EMTP prove the effectiveness of the above scheme.The main research content of this paper improves the accuracy of the integrator of the Rogowski coil electronic current transformer,and increases its ability to resist strong conducted electromagnetic interference,which provides theoretical basis and technical support for the design and operation of the Rogowski coil electronic current transformer.