Abstract: The present disclosure provides a method for modifying a gas density relay and a gas density relay having an online self-check function and a check method therefor. The gas density relay having an online self-check function is used for high-voltage and medium-voltage electrical devices, and includes a gas density relay body, a gas density detection sensor, a gas path blocking pressure regulation mechanism, an online check contact signal sampling unit and an intelligent control unit. The intelligent control unit controls a blocking member of the gas path blocking pressure regulation mechanism to move, so as to block a gas path between a first interface and a second interface.

Abstract: The application provides a modification of gas density relay, a gas density relay with online self-check function and its check method for high-voltage and medium-voltage electrical equipment. The gas density relay includes a gas density relay body, a gas density sensor, a pressure regulating mechanism, a valve, an online check contact signal sampling unit and an intelligent control unit. The pressure is increased or decreased by the pressure regulating mechanism to enable the contact action of the gas density relay body. The contact action is transmitted to the intelligent control unit through the online check contact signal sampling unit. The intelligent control unit detects the alarm and/or blocking contact signal operating value and/or return value of the gas density relay body according to the density value of the contact action; the check of the gas density relay can be completed without maintenance personnel on site.