It collects the value of pressure and temperature of SF6 gas in SF6 density relay.

The working principle and operating method of a newly developed automatic verification tester for SF6 density relay was introduced.

The SF6 gas density relay is an important component of observing SF6 gas density change,and its performance directly influences the safety operation of SF6 device.

The SF6 concentration monitoring system was integrated with the SF6 density monitoring system and the fault maintenance was integrated with the preventive maintenance to enhance the condition maintenance which takes the maximum reliability and the minimum cost as the objective.

In view of the main influencing factors including testing instrument, connecting gas circuit, ambient temperature and the impurity in gas sample of the field measurement on humidity of SF6 gas, the main causes are analyzed and the control methods are put forward, which can provide reference for field measuring on humidity of SF6 gas.

Optical signals occurred during the pre discharge and the breakdown over the spacer in sulfur hexafluoride gas are investigated by using a photomultiplier tube and a high speed framing camera under the fast oscillating impulse voltages (FOI) or lightning impulse voltages (LI).