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 Works protected by the First, the transformer gas

Gas protection of the transformer internal fault protection devices, and interlayer short circuit between the transformer turns, core failure, casing internal fault, the internal break in the windings and insulation deterioration and oil level fell failure can be sensitive to the action. Produce large amounts of gas when the oil-immersed transformer internal failure, because the decomposition of the arc will allow insulation materials and vary its intensity with the severity of the failure. Gas protection is the use of the reaction gas of the gas state relay (also known as gas relay) to protect the transformer internal fault.

Gas protection relay, the upper part of a sealed buoy the lower part is a metal bracket, both equipped with sealed mercury contacts. Floats and shield around the respective axis. In normal operation, the relay is full of oil, floats immersed in oil, in a floating position, the mercury contact is disconnected; tailgate due to their own weight and hangs down, the mercury contact is disconnected. Transformer internal minor fault, the gas speed is slow, gas rose to the storage cabinet on the way first stored in the upper space of the gas relay, so that the oil level dropped, the floats drop leaving the mercury contact closure connected to the extension of the signal, which is the so-called \"light gas\"; when the transformer internal catastrophic failure, the resulting strong gas gas, the fuel tank pressure transient sudden increase in oil flows oil pillow direction of impact, the impact due to oil flow file plate, baffle to overcome the resistance of the spring to drive the magnet move to the direction of reed contacts, the mercury contact closure connected to the trip circuit to trip the circuit breaker, which is the so-called \"gas\". Heavy Gas, immediately cut off all power connected to the transformer, thus avoiding the expansion of the accident, play a role in the protection of the transformer.

Gas relay different models of the pontoon, plate file, open cup. Most of the QJ-80 relay, the signal circuit connected to the Open Cup, the trip circuit to take over the tailgate. So-called gas protection signal action, referring to a variety of reasons, the Open Cup relay signal circuit contact closure, light plate lights.

Second, the scope of protection of transformer gas

Gas protection is the main protection of the transformer, it can reflect all of the fuel tank failure. Include: short circuit between the multi-phase short circuit in the fuel tank, Winding, winding and core or shell, core failure, the oil drop or oil spills, tap connection is bad or poor wire bonding. Gas protection action is rapid, sensitive, reliable and simple structure. But it does not reflect the failure of the tank external circuit (such as Lead), so we can not only protect the transformer internal fault protection device. In addition, gas protection is also easy in a number of external factors (such as earthquakes), the interference of malfunction, this must take appropriate measures.

, Transformers and gas protection installation

Gas relay is installed in the transformer to the connection of the storage cabinet pipeline installation should pay attention to:

The butterfly valve on the gas relay channels locked. Loose relationship, such as butterfly valve or other circumstances, if necessary, to let go of the oil in the oil pillow, in case you work in a large number of oil spills.

(2) before the installation of new gas relay, you should check whether the certificate of inspection, diameter, flow rate is correct, both inside and outside parts for damage, temporary banding internal if you want to open the final check floats, bumpers, signals and trip contact The action is reliable, and close to good deflation valve.

Gas relay shall be horizontally mounted, pointing to the direction of the arrow marked on the top cover to the oil pillow, the project allows the relay to the pipe axis direction to the direction of the oil pillow at one end slightly, but the tilt with the horizontal plane should not exceed 4.

(4) open the butterfly valve to the gas relay oil-filled, full of oil deflated deflation valve. Such as oil pillow with the capsule should be noted that oil-filled deflated ways to minimize and avoid gas into the oil pillow.

5 to protect the wiring, should prevent a wrong and short-circuit, to avoid the live operation, to prevent the conductive rod to turn the oil spill and a small ceramic head.

Put into operation before the insulation shake test and drive test.

Fourth, before the pilot project

The following inspection and testing of the gas relay should be made before the installation.

A general inspection items: windows, air release valve, control pin at the pinout terminals complete permeability, floats, open cup, windows complete crack.

(2) general test items:

(1) seal test: overall fuel pressure (for 20mPa pressure leak testing of the duration of 1h), there should be no penetration leakage.

(2) terminal dielectric strength test: the outlet terminals and the outlet terminals tolerance work frequency voltage 2000v for 1min available 2500V megger shake measuring insulation resistance, instead of shaking measured 1min power frequency withstand voltage, insulation resistance should be more than in 300mΩ .

(3) light gas action volume test: When the shell accumulate 250 ∽ 300cm3 air, light gas, should be reliable.

(4) Heavy Gas flow test.

Five routine inspections to projects

Project of routine inspections of the transformers, power transformers operating procedures DL/T572-95 provisions should first check the gas relay with or without gas, gas inspections should note the following points:

A gas relay to connect the tube on the valve in open position.

2 the transformer respirator should be in normal working condition.

(3) Gas protection connecting piece inputs should be correct. Letter

Oil pillow oil level should be at the right position, the relay is full of oil.

Gas relay waterproof cover must be solid.

6 relay terminals Department should not permeability, and measures should be able to prevent the intrusion of rain, snow, dust, power, and the secondary circuit should be waterproof, anti-oil and antifreeze and water in spring and autumn, anti- oil and antifreeze check.

Run of six transformer gas protection

Transformer in normal operation, gas relay work without any exception. Running state of the gas relay, its procedures in the following provisions:

A transformer to run the gas protection should be connected to the signal and trip OLTC gas protection connected to the trip.

Transformer in the operation of the following should be the protection of the heavy gas to change signal: a circuit breaker to control the two transformers, one of the transferred to the spare change, you should re-gas of a spare transformer signal; filter oil, fill oil-for-submersible pump or replace the purifier of the adsorbent and gas relay, opening and closing valve on the connection pipe; gas to protect its secondary circuit work; In addition to oil production sample and in the gas relay the upper part of the release valve to release gas at the open air in all other places to play, put oil and feed oil valve; oil level when the oil level of abnormal elevation or suction aspiration system anomalies need to hit the open air or put oil valve.

During the earthquake prediction should be determined according to the specific circumstances of the transformer and gas seismic performance of the relay operation mode of the heavy gas protection. The earthquake caused the outage of the transformer of the heavy gas protection action, in response to transformers and gas protection before operation check test to confirm no abnormality can be put into.

7, transformers and gas protection action of the main reasons

Light Gas action following reasons:

1 oil filter, fuel or cooling system is not tight as well as air into the transformer.

Temperature drop or spill, causing the oil level is below the light gas floats below the gas relay.

Transformer failure to produce a small amount of gas.

Transformer through the short-circuit fault. Through fault current under the action of the oil flow of the oil band to band speed, gas relay may malfunction when the pressure difference generated by the oil gap and winding lateral changes. Through fault current winding actions fever, when the fault current multiples, winding temperature rises rapidly, so that the oil volume expansion, resulting in the malfunction of the gas relay.

Gas relay or secondary loop failure.

The above factors are likely to cause gas to protect the signal action.

Eight transformer gas protection action after processing

Transformer Gas Protection Device should immediately be careful inspection, a careful analysis of the right judgments, to take immediate treatment measures.

(1) gas to protect the signal action immediately transformer inspection, identify the action reason is due to the accumulation of air, the oil surface to reduce secondary circuit failure or transformer internal confederation caused. Such as the gas off-gas relay, you should record the amount of gas, and observe whether the color and testing of the gas combustible, and take the sample gas and oil sample chromatographic analysis, according to the customs procedures and guidelines to determine the nature of the failure of the transformer. Chromatographic analysis is collected from the gas chromatograph contained hydrogen, oxygen, carbon monoxide, carbon dioxide, methane, ethane, ethylene, acetylene and other gases, qualitative and quantitative analysis, according to the components contained the names and contents accurately determine the confederation nature, development trends, and severity.

If the gas within the gas relay colorless, odorless and not flammable, chromatographic analysis to determine the air, the transformer can continue to run, and timely elimination of the defects of the inlet. If the gas combustible gas relay and the oil dissolved gas chromatographic analysis of abnormal results should be comprehensive judgment to determine the transformer whether the outage.

Gas relay trip, identify the cause to eliminate the fault may not be transformers in operation. To identify the reasons for the focus to consider the following factors to make a comprehensive judgment.

(1) whether the shortness of breath or exhaust deficiencies;

(2) protect and DC, and the secondary circuit is normal;

(3) The transformer that there are apparent anomalies reflect the nature of the fault;

(4) gas relay accumulation of gas is combustible;

(5) Gas relay Gas and oil dissolved gas chromatographic analysis;

(6) the necessary electrical test results;

(7) The action of transformer protection devices.

9, transformers, gas protection, anti-accident measures

Gas protection action, the light a protection action signal to alert maintenance personnel immediately transformer; heavy jump transformer switch, causing the transformer immediately to stop the run, can not guarantee the reliability of electricity supply, this gas protection against accidents measures:

The gas relay buoy changed files plate, contact changed to vertical in order to improve the reliability of the Heavy Gas.

2 in its terminals and cable lead terminal box to prevent the gas relay, leakage and short circuit, to take the rainproof measures.

Gas relay pinout oil line should be used.

Gas relay pinout and cables should be connected to the cable lead terminal box terminal