Gas insulated switchgear monitoring apparatus and method

A process for operating a gas monitoring apparatus to measure gas in a tank using sensors, controllers, and algorithms comprising the steps of:

• a controller acquires a gas pressure signal from a gas pressure sensor connected to said being monitored;
• said controller converts said gas pressure signal into a calibrated gas pressure value in engineering units of force per unit area;
• said controller acquires an atmospheric pressure signal from an atmospheric pressure sensor;
• said controller converts said atmospheric pressure signal into a calibrated atmospheric pressure value of atmospheric pressure in engineering units of force per unit area;
• said controller sums said calibrated gas pressure value and said calibrated atmospheric pressure value yielding a calibrated absolute gas pressure value;
• said controller acquires a gas temperature signal from a gas temperature sensor associated with a specific temperature location;
• said controller converts said gas temperature signal into a calibrated gas absolute temperature value in engineering units of absolute temperature;
• a user specifies a gas type;
• said controller uses said gas type to lookup a virial coefficient model equation;
• said controller uses said virial coefficient model equation and said absolute gas temperature to calculate a second order virial coefficient;
• said controller uses said second order virial coefficient, said absolute gas pressure, said absolute gas temperature, a gas constant, and a virial equation to calculate a first gas density value;
• said user specifies a first measurement frequency defining a first measurement time interval, and said controller repeats said above steps at the rate of said first measurement frequency developing a first time sequence of samples comprising said calibrated absolute gas pressure value, said calibrated absolute gas temperature value, and said first gas density value at each time separated by said first measurement time interval.