The modern power grid’s increased capacity and complexity have amplified short-circuit risks for transformers due to high loads and system capacities. Manufacturers must enhance transformer designs to withstand outlet short-circuits, a prevalent cause of recent damages.
During a short-circuit, excessive currents cause overheating and strong electric forces, leading to winding deformations and insulation damage. Swift on-site assessment is crucial to promptly repair or replace damaged coils, minimizing downtime and shipping costs. Moisture prevention measures must align with specific site conditions.
Effective preventive measures include optimizing winding designs to balance ampere-turns, reinforcing low-voltage coils with self-adhesive wires and robust insulation, and enhancing structural components like iron yoke clamps and pressure rings. Improved insulation processes and robust relay protection systems further mitigate risks.
Post-short-circuit, immediate assessment is essential to detect winding deformations and insulation damage. Oil chromatography and comprehensive electrical tests, including DC resistance measurement and frequency response analysis, guide decisions on transformer operability. Detailed inspection and analysis integrate gas chromatography data, electrical tests, and device operation, ensuring accurate fault diagnosis.
To minimize low-voltage outlet short-circuit failures, ensure robust insulation through closed busbars and upgraded insulation on transformer lead-out lines. Enhance phase insulation ratios using appropriate insulators, adjust switch cabinet sizes for optimal air insulation, and improve cable outlet structures.
Additional measures include installing arc suppression coil devices for ungrounded systems, disabling reclosing devices for permanent faults, enhancing pollution flashover protection, and verifying short-circuit resistance in aging transformers. Consider installing external series reactors for transformers prone to frequent short-circuit shocks.
Comprehensive prevention strategies entail strengthening distribution line maintenance, protecting against animal damage, and optimizing relay protection operation. Evaluate grid operation modes for layered zoning to reduce overall short-circuit capacities. Enhance lightning protection measures to prevent instantaneous faults caused by strikes.
These measures collectively enhance transformer resilience and operational safety against short-circuit accidents, ensuring reliable power supply in complex grid environments.
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