The Design Of SF₆ Gas State Monitoring System Of High Voltage Circuit Breaker

High-voltage breaker is important in power system.It influences the system's stability and reliability directly.SF₆ gas is an important insulation and arcing medium in high-voltage breaker,and influenced by physical condition a lot.Research on intelligent on-line monitoring technique of SF₆ gas to monitor its state can issue alerts to help staff promptly to eliminate the hidden danger that weaken the SF₆ gas,so it is necessary to power system.This paper firstly introduces a empirical equation of SF₆ gas,a pressure and temperature based calculation method of density and a method of accurately saturation vapor pressure curve fitting formulae.Secondly,it designs a method to judge SF₆ gas's state,including liquefaction,leakage,and so on,based on temperature and pressure value.It also introduces the hardware and the software design of the system.Then,the designer simulated the system to verify accuracy and timeliness of its alarm functions.Then the pressure and temperature sensors are calibrated by a lab experiment.Finally,the SF6 gas's liquefaction path is measured during its liquefaction and vaporization process,and the accuracy of formula and the equation are verified.It proves the warning logic is correct and timely and the complete system can run stably.