The Researches And Design Of New Electronic Current Transformers And The Software Of Its Digital Interface

Electronic Current Transformer (ECT) is a new kind of transformer whose output signalcan be connected with the intelligent digital device. It is the main component of digitalsubstation. The research of digital interface has very important significance for realizing thestandardization of communication. In this paper, the design of electronic current transformerwas based on PCB plane hollow coil and carried out in-depth research of the software of thedigital interface.Firstly，the paper summarizes the method of the primary conductor and secondary coiland put forward two ways of improving the accuracy which has been proved by experiment.The steady and transient performance have been analied. moreover, an experimental prototypehas been made and related experiments have been done; Consider that the electroniccomponents of traditional processing circuit are affected by environmental temperature easily,affecting the accuracy of the transformer. In view of the above problem, this paper presentsthat the digital integration can be used to instead of the analog integrator. The digitalintegration is based on trapezoidal algorithm. The FPGA is used for signal acquisition andcontrol of AD. The function for each module has been introduced in detail. A collector modulehas been made in lab and mainly focus on the software design; In order to realize thetransmission of sampled value of merging unit. Firstly, make a research of the IEC61850. Thispaper established the communication model of MU based on the analysis of MU and followthe IEC61850-9-2to realize the transmission of sampled value. In the hardwareimplementation, this paper proposed an idea of MU, which is based on FPGA and DSP. Thispaper focused software analysis and design of MU which is divided into three parts: datacache、data processing and data output.The result show that the new type electronic current transformer has high application andwide population prospect. The software simulation showed that this scheme can complete thebasic function of merging unit, which has laid a physical foundation for the equipmentinteroperability and the promotion of digital substation.