SF6 and SF6 mixed gas density relay calibrating device and method

Abstract

The invention relates to an SF6 and SF6 mixed gas density relay calibrating device and method. The device comprises a gas incoming apparatus, a gas exhausting apparatus, a calibration apparatus, and amain unit. The gas incoming apparatus and the gas exhausting apparatus are set in parallel and connected with each other, and are connected with the calibration apparatus through gas pipes. The output end of the calibration apparatus is connected with the input end of the main unit. The method achieves the verification of the SF6 and SF6 mixed gas density relay in the whole temperature range andthe whole pressure range, timely finds out the defects of the SF6 and SF6 mixed gas density relay, and prevents the damages to the density relay from causing a fault of power equipment. Compressed airis used for replacing SF6 gas, thereby preventing the emission of SF6 greenhouse gas, and protecting the environment.

Description

technical field [0001] The invention belongs to the field of calibration of gas density relays, and relates to a SF 6 and SF 6 Mixed gas density relay calibration device and method. Background technique [0002] Pure SF 6 (Sulfur hexafluoride) gas is a colorless, odorless, non-toxic, non-combustible gas at normal temperature and pressure. It has excellent insulating properties and arc extinguishing ability, and is an ideal insulating medium. With the rapid development of the power industry and the improvement of technical equipment, a large number of sulfur hexafluoride circuit breakers and fully enclosed combined electrical appliances have been continuously put into construction and operation, and the consumption of sulfur hexafluoride is increasing. [0003] However, SF 6 Gas also has its disadvantages in application: (1) It is sensitive to the uniformity of the electric field, and it can only show its advantages in a uniform or slightly uneven electric field; (2) SF d...

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Problems solved by technology

[0003] However, SF 6 Gas also has its disadvantages in application: (1) It is sensitive to the uniformity of the electric field, and it can only show its advantages in a uniform or slightly uneven electric field; (2) SF discharged into the atmosphere 6 The gas is difficult to degrade, exists for a long time, and has a cumulative effect on global warming; (3) SF 6 The price of gas is relatively high, which increases the cost

This method is mainly used in the field, but there are the following problems: (1) the temperature has a great influence, and it is difficult to ensure the accuracy; (2) the use of SF 6 The meter on the gas storage cylinder is the reading of the relative pressure gauge, the accuracy is very poor, and the accuracy cannot be guaranteed. In addition, for the density relay (absolute pressure relay) that uses the method of measuring the absolute pressure value, it may be directly generated in high altitude areas. Larger error; (3) SF 6 The density relay is actually used in the step-down process, but it is not consistent with the actual application, and it also affects the accuracy of the calibration.

[0007] (2) Using SF 6 Check the density relay during the deflation process of the equipment. This method has the same problems as (1) and (2) in the above (1), and the SF must be checked when deflated. 6 For gas recovery, special SF is required 6 Gas recovery device, very inconvenient

[0008] (3) Calibration in a constant temperature room. This method of calibration is carried out in a constant temperature environment, which eliminates the error caused by the temperature to the calibration, so the accuracy of the calibration is high, but the calibration time is long with this method. It is necessary to establish a special constant temperature laboratory and add full-time staff, which increases the difficulty of on-site work and is neither economical nor convenient.

Similarly, for density relays that use the method of measuring absolute pressure values, that is, absolute pressure relays, large errors may directly occur in areas with high altitudes.

[0009] (4) Currently used SF 6 The gas density relay calibrator has the same defect or error: it can only test SF at normal temperature. 6 The gas density relay is tested, but the SF cannot be realized in the full operating temperature range 6 Calibration of gas density relays, especially for SF at extremely low or high temperatures 6 Gas Density Relay for Calibration

[0010] (5) Most of SF 6 Gas density relay calibrator or calibration method, such as Chinese patents 201210347820.9 and 201220477478.X, the technical solution can only calibrate pure SF 6 Gas Density Relay, not Calibration SF 6 Mixed Gas Density Relay

[0011] (6) Various SF currently used 6 gas or SF 6 Mixed gas density relay calibration methods, such as Chinese patents 201310641562.X, 201210023988.4 and 201210347820.9, have the same defects or errors in their technical solutions: these SF 6 gas or SF 6 The mixed gas density relay calibration methods all use SF 6 The gas is inspected, and after the inspection is completed, SF 6 The gas has to be discharged into the atmosphere, causing environmental pollution

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