Basic Principle of Density Relay Calibration and the Necessity of Calibrating SF6 Relay

1. It is necessary to calibrate SF6 relay

SF6 switch is a high voltage appliance widely used in power system. The reliable operation of SF6 switch has become one of the most concerned problems in the power supply department. SF6 relay is an important component used to monitor the SF6 gas density change in SF6 switch body in operation. Its performance directly affects the safety of SF6 switch operation.  Due to the infrequent action of SF6 gas density relays in field operation, inflexibility and poor contact contact often occur after a period of time. Some density relays also have poor temperature compensation performance. When the ambient temperature changes, SF6 relays often misoperate. Therefore, the preventive test procedures of power equipment stipulate that each SF6 switch user unit shall periodically calibrate SF6 gas density relay. In view of the actual operation, it is also very necessary to calibrate the SF6 relay and pressure gauge regularly in the field operation.

2. Basic principle of SF6 relay calibration

A SF6 gas density relay that can be directly calibrated without disassembly can not only charge the sulfur hexafluoride electrical equipment in the same position, but also enable the operator to directly calibrate the density relay without disassembling the density relay or additional open and close operation of the airway, and ensure the sealing of the sulfur hexafluoride electrical switch. It has the function to prevent the misoperation of calibration. At the same time, because there is no need to disassemble, it will not damage its sealing surface and sealing ring, and it will not affect its sealing performance, to ensure the safe operation of SF6 electrical equipment.

(1) The air charging port, water testing port, calibration port and gas shut-off valve port are the same port. In the same position, the SF6 electrical equipment is charged and water tested or the SF6 gas path of SF6 electrical equipment is shut off to calibrate the density relay, which minimizes the air leakage point.

(2) Direct calibration of SF6 relay can be realized without additional open and close operation of the airway, and no opening and closing marks need to be set, which can completely prevent misoperation and fully ensure the sealing and operation safety of SF6 electrical equipment.

(3) Integrated welding, less leakage point, all use argon arc welding for automatic welding, all use helium mass spectrometer for leak detection, to ensure the sealing performance.

(4) Small shape, can be suitable for a variety of SF6 electrical equipment, complete specifications with more than 40 kinds, basically covering the imported SF6 electrical equipment.

(5) The new table glass and contact lead line sealing technology, can ensure that the contact is not oxidized, greatly improve the service life, can ensure the long-term sealing of the shell, ensure the accuracy of the product, avoid the occurrence of wrong action.

(6) High precision, stable compensation performance.

(7) Control and instruction as a whole, easy to use.

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