Error Analysis of SF6 Density Relay in Pressure Monitoring of GIS Chamber

Abstract

The paper analyzes the GIS pressure monitoring in UHV substation and compares the results of ideal gas state equation and Beattie-Bridgman equation in the calculation of SF6 pressure and density. It is pointed out that the latter is closer to the actual situation. Through calculation and analysis， it is concluded that the values of common chamber pressure， with the compensation pressure being 0.05 MPa， are 0.3 MPa， 0.35 MPa， 0.40 MPa， 0.45 MPa， 0.50 MPa， 0.55 MPa， and 0.60 MPa corresponded to low temperature values of -25.03℃， -18.06℃， -12.86℃， -8.79℃， -5.55℃， -2.90℃， and -0.69℃ respectively. It is pointed out that the air chambers with rated pressure being 0.45 MPa and above in East China may be compensated and cause low pressure alarm. If this happens， it is necessary to check the leakage of the gas chamber and analyze the pressure compensation under the condition of having excluded the leakage.

Keywords

• gis pressure
• sf6 density relay
• temperature compensation