Due to power outages and difficulties in disassembly, the operating SF6 gas density relay may exhibit phenomena such as inflexible action and poor contact, which can easily lead to false operation of the SF6 relay. Therefore, it is necessary to periodically calibrate the SF6 relay. In order to facilitate on-site calibration and reduce the risk of equipment damage and gas leakage, it is recommended to install three-way valves on SF6 equipment.
One interface of the three-way valve is connected to the main body for connecting and isolating the main body gas chamber; one interface is used for installing the density relay; one interface uses a self-sealing interface, which serves as the on-site calibration port, testing port, and charging port.
Working principle: In the normal working state of the density relay three-way valve (i.e., non-calibration state), the gas path of the device interface is connected to the gas density relay, and the self-sealing gas replenishing port is locked with a protective cover. A sealing ring is installed on the inside of the protective cover to ensure the overall sealing reliability of the three-way valve. The three-way valve has a switch to control the connection of the main body gas path as needed.
If calibrating or replacing the SF6 gas density relay, adjust the switch on the three-way valve to control the connection between the main body and the relay, and isolate the main body from the relay, thereby separating the relay. Then, use a standard gauge or calibration equipment to gradually release the gas from the SF6 relay, and complete the calibration or replacement of the gas density relay.
With the use of a three-way valve, the calibration of the SF6 relay can be achieved without power outage or disassembly, making the on-site calibration work of the density relay very simple. At the same time, the calibration port on the three-way valve can be used for SF6 moisture, decomposition product, purity testing, and gas charging, ensuring the safe and reliable operation of the power grid.
The technical parameters of the three-way valve:
Material: Aluminum/Copper alloy/Stainless steel
Nominal diameter: 6, 8, 12, 20mm
Operating temperature: -40°C to +60°C
Leakage rate: ≤1×10-9Pa·m3/s
Maximum working pressure: 1.0 MPa
Shock resistance: 50G
Protection level: IP65