Research And Design Of Data-sampling System In Electronic Transformer

With the incessant improvement of transmission capacitance and rated voltage in power system,conventional ferromagnetic transducers have several shortcomings.It have been already difficult to meet the need that network develop towards automation,standardized and digitized direction,In this case,it is an inevitable trend that conventional ferromagnetic transducers will be taken place by electronic transformer.This dissertation is devoted to correlative research and design on data-sampling system in high voltage side.Rogowski coil is the current sensor.The basic principles of Rogowski coil are summarized,which include the equivalent circuit and the vector diagram of Rogowski coil, the analysis to static characteristic and transient characteristic,and the calculation of electomagnetism parameter.Based on these theories,design one high-precision PCB Rogowski coil.Capacitor voltage divider is the voltage sensor.Its principle and model structure are discussed in this paper,and according to its self-defects and the electromagnetic interference in its working enviroment,one electromagnetic compatible method is designed.The performance of integrator is always one of the important factors which influence the accuracy and reliability of Rogowski current transducer.The analogue integrator has the advantages of simple structure,high response speed and large dynamic range.The digital integrator has the advantages of stable performance and high accuracy.The advantages of the latter have made it a hot problem of studying the utility of Rogowski current transducer in recent years.This paper issues a set of methods of digital integrator designing,which include the choice of integration algorithm,the determine of the sampling rate and the resolution of the integration input,the universal structure of digital integrator,dealing with the initial value.In order to guarantee the data-sampling system run smoothly,the paper only adopts optical power supply method.How to reduce the power comsumption is one of the key steps in the design.This paper introduces some useful ways to make the data-sampling system's power consumption lower,then analyzes the characteristics of laser,photocell and photo-electric transfer device.Based on the characteristics,laser driving circuit is improved,greatly reduces the system's power comsumption,ensures the system run smoothly in low power supply.The paper summarizes at last,and brings out the problems needed to be solved in the future.