What is the gas relay and its role introduction

Posted by: enthusiast  • Information section:Electronic project

Gas relay
Gas relay (also known as gas relay) is a kind of protection device used in transformers. It is installed in the pipeline between the oil conservator and the fuel tank of the transformer. When the internal fault of the transformer is used to decompose the oil to generate gas or cause oil flow, Actuate the contact of the gas relay, turn on the specified control loop, and issue a signal alarm (light gas) or activate the protection component to automatically cut off the transformer (heavy gas).

The light gas mainly reflects the gas decomposed by the oil rising into the gas relay during operation or slight failure, the air pressure lowers the oil level, the open cup of the relay falls with the oil surface, and the light gas reed contact is turned on to signal, when the gas is inside When there is too much gas, the gas can be released by the gas nozzle of the gas relay.

Heavy gas is mainly reflected in the severe internal fault of the transformer (especially the failure of other transformer protection such as turn-to-turn short circuit), which generates strong gas to push the oil flow to impinge the baffle. The magnet on the baffle attracts the heavy gas reed contact. The contact is turned on and tripped.

The gas relay is divided into a carrier gas relay (the fuel pipe radius is generally 50mm or 80mm) and the body gas relay (the fuel pipe radius is generally 80mm). Gas relays are available in different types such as float type, baffle type, and open cup type. For example, in the QJ-80 type relay, the signal circuit is connected to the open cup, and the trip circuit is connected to the lower baffle. The so-called gas protection signal action means that the signal circuit contacts of the open cup in the relay are closed due to various reasons, and the light plate light is on.

The role of gas relay

The role of gas relay
Gas relay is a protection device for preventing gas accidents. In the power system, the gas relay is usually installed in the pipeline between the oil storage tank and the fuel tank. When the internal fault occurs in the transformer, the transformer oil is decomposed to generate gas or surge. Trigger to turn on the specified control loop, and send out the signal in time. The more serious the fault, the more gas gas is generated, the faster the flow rate is. According to the degree of gas, it is divided into light gas and heavy gas. In the case of heavy gas, protection The component automatically cuts off the transformer to reduce the loss of accidents.

The role of transformer gas relay
After the newly installed or overhauled transformer, during the process of refueling and filtering, the air will be brought into the fuel tank of the transformer with a little care. If the air is not discharged in time before being put into operation, after the transformer is put into operation, as the oil temperature rises, the oil in the oil tank will form a convection, and the air will be "caught out" of the oil surface, thereby causing the gas relay to operate. Generally, the more gas is present inside, the more frequently the gas breaker operates.

In the initial stage of operation, if the gas relay is found to be moving frequently, it should be comprehensively analyzed according to the sound, temperature, oil level, fueling and oil filtering conditions of the transformer. If the transformer is operating normally, it can be determined that it is entering air. Otherwise, the gas should be taken as a ignition test to judge whether the transformer itself has faults and the nature of the fault, so that corresponding measures can be taken to eliminate it in time to avoid the expansion of the fault and ensure the safe operation of the transformer.

Processing after transformer gas protection action

After the transformer gas protection action, it should be carefully checked, carefully analyzed, correctly judged, and immediately taken measures.
1. When the gas protection signal is activated, immediately check the transformer to find out the cause of the operation, whether it is caused by accumulated air, oil level reduction, secondary circuit failure or internal transformer failure. If there is gas in the gas relay, the gas quantity should be recorded, observe the color of the gas and whether it is flammable in the test, and take the gas sample and the oil sample for chromatographic analysis. The fault nature of the transformer can be judged according to the closing rules 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 gas chromatograph, according to the name and content of the components. Accurately determine the nature of the failure, development trends, and severity. If the gas in the gas relay is colorless, odorless and non-flammable, and the chromatographic analysis judges that it is air, the transformer can continue to operate and eliminate the intake defects in time. If the gas in the gas relay is flammable and the chromatographic analysis result of the dissolved gas in the oil is abnormal, it should be judged comprehensively to determine whether the transformer is shut down. The transformer in operation should be done well, load reduction preparation, and maintenance.
2. When the gas relay is tripped, the transformer must not be put into operation until the cause is eliminated. In order to identify the reasons, the following factors should be considered and comprehensive judgments should be made. (1) Whether the breathing is not smooth or the exhaust is not exhausted; (2) Whether the secondary circuit such as protection and DC is normal; (3) Whether the appearance of the transformer clearly reflects the abnormal nature of the fault; (4) The gas accumulated in the gas relay (5) Chromatographic analysis results of gas and oil dissolved in gas relay; (6) necessary electrical test results; (7) operation of other relay protection devices of transformers.


read ()  •  Mar 11, 2019  •  Edit



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