Key Inspection Items for Outdoor Oil-Immersed Transformers in Rainy Seasons

Rain,high humidity,lightning and waterlogging bring multiple risks to outdoor transformers.The patrol focuses on waterproofing,drainage,lightning protection,insulation,sealing and operational status to eliminate hidden dangers in advance.

1.Waterproof&Anti-Waterlogging Inspection

Check the transformer foundation,base and surrounding ground for ponding.Ensure drainage ditches and drainage holes are unblocked to prevent water from submerging the base.

Inspect cable trenches,cable inlets and terminal boxes.Confirm all sealing gaskets are intact and tightly closed to stop rainwater infiltration.

Check breather,oil level gauge and valve parts.Verify waterproof covers are installed properly;replace damp silica gel in breathers timely.

For pole-mounted transformers,check bracket fixation to avoid tilt caused by soft soil after heavy rain.

2.Sealing&Oil Leakage Check

Thoroughly inspect welds,flanges,manhole covers and gasket joints for oil seepage or leakage.Rainwater will accelerate corrosion and worsen leakage.

Observe the oil level inside the conservator.Keep it within the standard range;replenish qualified insulating oil in time if the level is too low.

Check for oil stains around the body.Clean accumulated oil and dirt to prevent surface flashover in wet conditions.

3.Insulation&External Live Parts Inspection

Examine bushings,insulators and busbars.Remove dust,bird droppings and mud on the surface to prevent creepage discharge under damp environment.

Check for cracks,chipping or glaze peeling on porcelain parts.Replace damaged insulators immediately.

Ensure sufficient safety clearance between live parts and adjacent metal components to avoid short circuits caused by water mist.

4.Lightning Protection&Grounding System

Inspect surge arresters for damage,cracks or leakage traces.Verify firm installation and reliable wiring.

Check grounding wires,connecting terminals and grounding electrodes.Clear rust,tighten loose connections and confirm grounding resistance meets requirements.

Inspect overhead ground wires and lightning rods along incoming lines to guarantee complete lightning shielding.

5.Operating Parameters&Abnormal Phenomena

Monitor oil temperature,load current and voltage.Avoid long-term overload in rainy weather which may trigger overheating faults.

Listen to operating sound.Continuous abnormal buzzing or intermittent discharge noise indicates potential insulation defects.

Check thermometer,gas relay and other protection components.Ensure alarm and trip functions work normally.

6.Auxiliary&Protective Devices

Check cooling fans and radiators.Clear debris blocking heat dissipation gaps.

Inspect door locks and protective enclosures.Keep them closed well to prevent rain and small animals from entering.

Confirm all warning signs are intact and eye-catching.

7.Post-Heavy Rain Special Recheck

After torrential rain or thunderstorms,arrange a special patrol:focus on new waterlogging,newly appeared oil leakage,flashover marks on insulators and abnormal protection actions.Deal with all defects promptly.

References

APA 7th Edition

Liu,S.,&Zhang,W.(2022).Flood prevention and daily patrol management of outdoor distribution transformers in rainy seasons.Electrical Equipment,23(8),71-76.

MLA 9th Edition

Liu,Si,and Wei Zhang."Flood Prevention and Daily Patrol Management of Outdoor Distribution Transformers in Rainy Seasons."Electrical Equipment,vol.23,no.8,2022,pp.71-76.

IEEE Style

S.Liu and W.Zhang,"Flood prevention and daily patrol management of outdoor distribution transformers in rainy seasons,"Electr.Equip.,vol.23,no.8,pp.71-76,2022.