Abstract:As essential equipment to ensure the safe operation of electrical equipment, the SF6 density relay needs an enormous workforce and material resources to be calibrated regularly. There are not only a large number of density relays to be calibrated but also some problems in the calibration process, such as low efficiency, high cost, and error-prone data entry. Therefore, it is of great practical significance to intelligently upgrade the calibration process. In order to solve these problems encountered in the maintenance and support of a large number of SF6 density relays in the power system, with the help of hierarchical distributed thinking, a technical system implementation framework for unified online calibration of essential instruments and meters in the industrial field through cloud edge-end collaboration is proposed. On this basis, the technical system has been applied in engineering. Under the guidance of the technical framework of collaborative online calibration at cloud edge, a scheme of adding a lightweight online calibration device to the existing density relay is proposed. So that the density relay can automatically complete the calibration and report the calibration results during the operation of electrical equipment, which effectively solves the problem that the current density relay needs to be manually calibrated after the power failure of electrical equipment. Experimental verification and comparison test with the SF6 density relay calibrator have proved that the precision of this device is similar to that of the calibrator. The device can meet the calibration requirements of the SF6 density relay. It can be used to support the establishment of a unified online calibration system for SF6 density relay and solve the painful problem of SF6 density relay calibration.