The Design Of Three-Phase D-dot Sensor Based On The Electric Field Inverse Problem And The Research Of Measurement System

A non-contact?small and intelligent voltage transformer should be made to meet the development of smart and high-voltage grid in the future. Currently, the research of D-dot electric field sensor mainly solves the problems of single phase measurement, and in three phase transmission lines, due to electric field coupling, will lead to a measurement system of capacitance matrix expansion, the change of the electric field distribution. When the sensor working in single-phase circuit and three-phase circuit respectively, the results will be different. Because of the difference, when design the three-phase D-dot electric field sensor, we need to consider the distribution parameters and adjacent electric field effect.To realize non-contact measurement of three-phase voltage based on the theory of electric field inverse problem and charge simulation method. The mainly working:(1)Studied the basic measurement principle to electric field coupling electric field sensor, and prepare for the design and optimization of the probe. For complex spatial distribution of three-phase electric field,Potential equation and boundary condition formulation of the space electric field problem are expressed by using A ? method, and then built the field-circuit coupling mathematical model directly based on the electric displacement vector.(2)In order to design a D-dot electric field sensor suitable for measure the space electric field of three phase power line, this paper proposes a design of electric field sensor based on field-circuit coupling method and analysis method. The method based on electric field finite element analysis model and equivalent circuit model of electric field sensor, using field-circuit coupling of collaborative simulation technology, can analyze the mutual coupling between the electric field sensor and equivalent circuit effectively, and realize parameter design and optimization of field sensors.(3)Design the hardware circuit for three sensor signals used for synchronization acquisition, and realize digital sensor of the output voltage signal. The D-dot voltage transformer simulation system constructed by voltage waveform through WIFI wireless network with LabVIEW technology, and realize gathering, analysis, and save of the the data.(4)Built single-phase test platform to calibration the D-dot electric field sensor, and make experiment about the phase error, linearity, steady state and transient state calibration. At the same time, building a three-phase voltage transformer simulation test platform. The result shows that the sensor have a quick response with rapidly changing primary voltage and high accuracy of measurement. The probe measuring system can meet the goals of synchronization acquisition for multi-signals, signal without distortion.