Emergency Handling for Oil-Immersed Transformers When Flooding Submerges the Base

Flooding around or submerging the transformer base brings risks such as water ingress,insulation breakdown,short circuit and electric leakage.Follow standardized emergency procedures in the order of power cut,on-site isolation,drainage,inspection and recovery to avoid safety accidents and equipment damage.

1.Immediate Power Shutdown&Safety Isolation

Cut off the high-voltage and low-voltage power supplies of the transformer immediately in accordance with operating regulations.Implement lockout-tagout and hang warning signs to prevent accidental energization.

Set up safety barriers around the flooded area and evacuate irrelevant personnel.It is strictly forbidden to wade into the water or touch the transformer body,metal brackets and grounding parts to prevent electric shock.If the water level keeps rising rapidly,arrange personnel to move portable equipment and valuables to higher ground.

2.Block Water&Accelerate Drainage

Take measures to stop the continuous inflow of rainwater first.Use sandbags,baffles or waterproof boards to build retaining walls around the foundation to block external water.

Deploy water pumps,water scoops and other tools to drain accumulated water.Prioritize draining water near the transformer base,cable trenches and grounding devices.Keep the drainage outlet unobstructed to prevent water backflow.Do not start drainage work before power is fully cut off.

3.Check for Water Infiltration&Sealing Conditions

After the water level drops below the base,conduct a comprehensive inspection:

Check welds,flanges,gaskets,cable inlets and bushings for water seepage into the tank.

Inspect the oil level gauge,breather,valves and auxiliary components to confirm no rainwater enters the oil chamber.

If water has penetrated the transformer interior,mark the fault area clearly and prohibit power transmission.

4.Dehumidification&Drying Treatment

Thoroughly clean mud and stains on the surface of the equipment,base and surrounding ground.Use dry cloths,dry compressed air or industrial fans to blow and dry damp parts.

For components with suspected internal moisture such as bushings,terminal boxes and control cabinets,adopt forced ventilation or dehumidifiers for continuous drying.In humid environments,extend the drying time to ensure all damp parts are completely dry.

5.Electrical Performance Testing(Key Step)

Carry out a full set of tests before re-energization:

Measure insulation resistance of windings to ground and between phases.Compare the data with historical records;stop operation if the value is obviously lower than the standard.

Test dielectric strength of insulating oil.If moisture content exceeds the limit,perform oil filtration or full oil replacement.

Check grounding resistance,loop continuity and protection device functions to ensure all indicators meet operating standards.

6.Gradual Re-energization&Post-Operation Monitoring

If all test results are qualified,perform no-load trial operation first.Close the switches step by step,and continuously monitor operating noise,oil temperature,oil level and leakage status.

Maintain a 24-hour special patrol after formal power transmission.Once abnormal vibration,overheating or oil leakage is found,cut off power immediately for re-inspection.

7.Post-Flood Preventive Measures

Reinforce the transformer foundation and raise the base height properly for areas prone to waterlogging.Improve drainage ditches and add drainage holes around the foundation.Install waterproof covers for breathers,terminal boxes and other vulnerable parts.Regularly inspect sealing performance before rainy seasons.

References

APA 7th Edition

Zhao,G.,&Ma,L.(2023).Emergency disposal and recovery technology of power distribution equipment under flood disaster.Power System Protection and Control,51(11),92-98.

MLA 9th Edition

Zhao,Gang,and Lin Ma."Emergency Disposal and Recovery Technology of Power Distribution Equipment Under Flood Disaster."Power System Protection and Control,vol.51,no.11,2023,pp.92-98,

IEEE Style

G.Zhao and L.Ma,"Emergency disposal and recovery technology of power distribution equipment under flood disaster,"Power Syst.Prot.Control,vol.51,no.11,pp.92-98,2023,