Method for modifying gas density relay, and gas density relay having online self-checking function and checking method therefor

A gas density relay having an online self-check function, comprising:

• 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;
• wherein
• the gas density detection sensor is in communication with the gas density relay body;
• a gas path of the gas density relay body is connected to a first interface of the gas path blocking pressure regulation mechanism;
• the gas path blocking pressure regulation mechanism is further provided with a second interface in communication with electrical device, and the gas path blocking pressure regulation mechanism is configured to block a gas path between the first interface and the second interface, and to regulate a pressure rise and fall of the gas density relay body, thereby generating contact signal action of the gas density relay body;
• the online check contact signal sampling unit is directly or indirectly connected to the gas density relay body and is configured to sample a contact signal of the gas density relay body;
• and
• the intelligent control unit is separately connected to the gas density detection sensor, the gas path blocking pressure regulation mechanism and the online check contact signal sampling unit, and is configured to control the gas path blocking pressure regulation mechanism, collect a pressure value and a temperature value, and/or collect a gas density value, and detect a contact signal action value and/or a contact signal return value of the gas density relay body;
• wherein
• the contact signal comprises an alarm signal and/or a blocking signal.