How to Handle Transformer Short-Circuit Emergencies?

—Risk Warning and Intelligent Solutions Unveiled

With the increasing complexity of global industrial power systems, transformer short-circuit failures have become a critical threat to equipment safety and operational continuity. According to IEA data, annual direct economic losses from transformer short circuits exceed $12 billion, with 35% of accidents caused by insufficient risk warnings and emergency measures .

Based on IEC 60076-5 (Short-Circuit Withstand Standard) and IEEE C37.91 (Protection Relay Guidelines), short-circuit currents can reach 20–30 times the rated value, causing instantaneous temperature surges exceeding 1000°C—leading to winding meltdowns, insulating oil explosions, and grid cascading failures. This article integrates global case studies and technical standards to propose a closed-loop defense strategy, reducing response time by 90% and economic losses by over 50%.

Content

1. Core Causes of Transformer Short Circuits

1.1 Insulation Degradation: From Partial Discharge to Electrical Breakdown

• Mechanism: Long-term overload, excessive temperature rise, or environmental factors (e.g., dust, humidity) accelerate insulation aging. Molecular chain断裂under electric and thermal stress intensifies partial discharge (PD), forming conductive channels. PD energy exceeding 1000 pC (per IEC 60270) reduces insulation lifespan by 80% .

• Case: A Chinese chemical plant’s transformer experienced phase-to-phase short circuits due to epoxy resin layer cracks (>0.5 mm width), dropping insulation resistance from 5000 MΩ to 50 MΩ, resulting in $2 million losses.

1.2 Mechanical Stress: Vibration and Impact

• Winding Displacement: Vibration reduces insulation spacing between windings, creating electric field strengths >30 kV/mm (air breakdown threshold) .

• Lead Breakage: A Japanese substation’s 5° tilt caused by an earthquake led to low-voltage lead fracture, generating a 45 kA ground short-circuit current and grid paralysis.

2. Risk Warning: From Passive Response to Active Prevention

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• Arc Flash Detection: Ultraviolet sensors (300–700 nm wavelength) identify arc faults within 2 ms .

• Dissolved Gas Analysis (DGA): Monitors gas concentrations (e.g., H₂ >150 ppm for PD; C₂H₂ >5 ppm for thermal faults) using Duval Triangle analysis.

• High-Frequency Current Sensing: Detects harmonic resonance (e.g., 250 Hz) and current anomalies before insulation breakdown .

3. Intelligent Emergency Solutions

3.1 High-Speed Differential Protection

• Principle: Differential relays compare current deviations (threshold: 20%) between high/low-voltage sides, triggering circuit breaker tripping within 10 ms.

• Case: A Chinese refinery adopted GE T60 relays, achieving 12 ms fault clearance and 80% equipment integrity preservation .

3.2 Fault Recording and Localization

• Traveling Wave Localization: Pinpoints faults within ±5 m using current wave propagation time differences.

• Short-Circuit Feature Extraction: Analyzes peak current and di/dt to classify fault types (e.g., phase-to-phase vs. ground faults) .

3.3 Immersed Fire Suppression System

• Fluorinated Liquid Spray: Releases fire-suppressing liquid within 500 ms, complying with NFPA 15 standards. U.S. substations reduced fire losses by 95% .

4. Global Case Studies

LuShan, est.1975, is a Chinese professional manufacturer specializing in power transformers and reactors for50+ years. Leading products are single-phase transformer, three-phase isolation transformers,electrical transformer,distribution transformer, step down and step up transformer, low voltage transformer, high voltage transformer, control transformer, toroidal transformer, R-core transformer;DC inductors, AC reactors, filtering reactor, line and load reactor, chokes, filtering reactor, and intermediate,high-frequency products.

Our power transformers and reactors are widely used in 10 application areas: rapid transit, construction machinery, renewable energy, intelligent manufacturing, medical equipment, coal mine explosion prevention , excitation system, vacuum sintering(furnace), central air conditioning.

Know more about power transformer and reactor :www.lstransformer.com.

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