Causes of signal action of the hottest gas protect

Causes of signal action of gas protection device and anti accident measures

this paper expounds the causes of signal action of gas protection device and the basic principles and treatment methods of accident analysis and diagnosis, and puts forward anti accident measures

I. main reasons for gas protection signal action:

1. Air enters the transformer due to lax oil filtration, refueling or cooling system

2. The oil level is below the light gas float of the gas relay due to temperature drop or oil leakage

3. A small amount of gas is generated by transformer fault

4. The transformer has a through short circuit fault. Under the action of through fault current, the oil flow speed between oil gaps is accelerated. When the pressure difference between the oil gap and the outside of the winding changes greatly, the gas relay may malfunction. The through fault current causes the winding to act and heat up. When the fault current multiple is large, the winding temperature rises rapidly, causing the volume of oil to expand, resulting in the misoperation of the gas relay

5. Gas relay or secondary circuit failure

the above factors may cause gas protection signal action

II. Anti accident treatment of gas protection device action:

(I) after the gas protection device of transformer acts, it should be carefully checked, carefully analyzed, correctly judged, and treatment measures should be taken immediately

1. When the gas protection signal acts, check the transformer immediately to find out the cause of the action, whether it is caused by the accumulation of air, the reduction of oil level, the failure of the secondary circuit or the internal Confederation of the upper transformer. If there is a gas break in the gas relay, record the amount of gas, observe the color of the gas and whether it is combustible in the test, and take gas samples and oil samples for chromatographic analysis. The fault nature of the transformer can be judged according to the relevant regulations and guidelines. Chromatographic analysis refers to the qualitative and quantitative analysis of hydrogen, oxygen, carbon monoxide, carbon dioxide, methane, ethane, ethylene, acetylene and other gases contained in the collected gases with a chromatograph, and the accurate judgment of the nature, development trend, and severity of the Confederacy according to the name and content of the components contained

2. If the gas in the gas relay is colorless, odorless and nonflammable, and the chromatographic analysis determines that it is air, the transformer can continue to operate and eliminate the air inlet defect in time

3. If the gas in the gas relay is combustible and the chromatographic analysis result of dissolved gas in the oil is abnormal (4) the viscosity of the oil is too low, it should be comprehensively judged to determine whether the transformer is shut down

(II) when the gas relay acts and trips, the transformer shall not be put into operation until the cause is found out and the fault is eliminated. In order to find out the cause, the following factors should be considered and a comprehensive judgment should be made

1. Whether there is poor breathing or incomplete exhaust

2. Whether the secondary circuits such as protection and DC are normal

3. Whether the appearance of the transformer has abnormal phenomena that clearly reflect the nature of the fault

4. Whether the gas accumulated in the gas relay is combustible

5. Chromatographic analysis results of gas in gas relay and dissolved gas in oil

6. Necessary electrical test results

7. Operation of other relay protection devices of transformer

(III) anti accident measures for gas protection:

gas protection action, the light one sends a protection action signal to remind the maintenance personnel to deal with the transformer immediately; If the transformer switch is switched off, the transformer will stop running immediately, which cannot ensure the reliability of power supply. Therefore, the torsion tester of piezoelectric load sensor has the advantages of anti accident measures for gas protection:

1. Change the lower pontoon of the gas relay to a baffle plate, and the contact to a vertical, so as to improve the reliability of heavy gas action. Do stretching, 90 degree peeling and roller peeling experiments

2. In order to prevent gas relay 7.1.3 when the product has one of the following conditions, type inspection should be carried out; If the device is short circuited due to water leakage, rain proof measures should be taken on its terminal and cable lead terminal box

3. The outgoing line of gas relay shall be oil proof wire

4. The outgoing line and cable of gas relay shall be connected to the terminal in the cable lead terminal box respectively

III. conclusion

after the gas signal of the transformer acts, the operator must check the transformer, find out the cause of the action, and immediately report to the superior dispatcher and the leader in charge. The superior leader in charge should immediately send someone to the site to extract the gas sample, oil sample and body oil sample of the relay for chromatographic analysis. Take corresponding countermeasures according to relevant guidelines and on-site analysis conclusions to avoid accidents and ensure the safe and economic operation of transformers