A Study Of Safety Technique Upon Collaborative Information Between Digital Substations

Digital substation has become the technology development trend of new generation substation with the development of the smart grid. Currently, equipment operation security and reliability have been the focus of attention in the course of digital substation technology development. Meanwhile, the cyberlization and informatization of digital substation, which provide reliable redundant information for the research on security techniques of station equipment, ensure the feasibility of implementing multiple new fault diagnosis methods and misoperation-proof locking technique based on inter-station cooperative information.This paper conducts research on electronic instrument transformer collaborative diagnosis method based on inter-station information and misoperation-proof locking method for inter-station operation, and makes an analysis of present research situation of power system security technology based on inter-station cooperative information, the existing fault diagnosis methods of electronic instrument transformer and the defects and shortcomings of misoperation-proof locking technical measures. The digital substation architecture determines the advantages of information sharing and state diagnosis. Based on this characteristic, this paper proposes using inter-station cooperative information to implement the on-line diagnosis and misoperation-proof locking of electronic instrument transformer and switching apparatus respectively through analyzing their potential safety hazard.The theoretical basis of inter-station cooperative information technique is information fusion technology, with data communication and sample synchronization as the key influencing factors, Through analysis of inter-station data communication and sample synchronization mode, this paper puts forward the correspondent data communication mode and sample synchronization method respectively.Study on the characteristics of data transmission has been made by conducting characteristic experiment of the measuring channel of electronic instrument transformer. A method of inter-station collaborative diagnosis based on wavelet method is proposed in combination with the dynamic change of the measured value of electronic instrument transformer in different working conditions of power grid. The validity of the proposed scheme is verified by the simulation using typical example and MATLAB Wavelet Toolbox.Digital substation misoperation-proof locking method for inter-station operation based on cooperative information has been proposed. By colleting the grounding switch state information of the remote end, the proposed system realizes the automatic blocking of power transmission line closing circuit while the grounding switch of both or multiple sides of the lines is left in the detent position. The long-term field engineering test shows that this system can effectively resolve the issue of pre-warning and blocking to prevent grounding switch close fault, and guarantee the equipment and personal security.