Substation equipment requires regular maintenance to ensure reliability, safety, and efficiencyin power transmission and distribution. Proper maintenance prevents failures, extends equipment life, and minimizes downtime.

1. Types of Maintenance

A. Preventive Maintenance (PM)

• Scheduled inspections and servicing to prevent failures.

• Includes cleaning, lubrication, testing, and adjustments.

• Examples:

◦ Oil testing in transformers.

◦ Thermal imaging of connections.

◦ Insulation resistance tests on circuit breakers.

B. Predictive Maintenance (PdM)

• Uses condition monitoring to predict failures.

• Techniques:

◦ Partial Discharge (PD) testing (for switchgear & transformers).

◦ Vibration analysis (for rotating equipment).

◦ Dissolved Gas Analysis (DGA) (for transformers).

C. Corrective Maintenance (CM)

• Repairs done after a failure occurs.

• Example: Replacing a failed circuit breaker.

D. Condition-Based Maintenance (CBM)

• Maintenance performed based on real-time monitoring (e.g., SCADA alerts).

2. Key Substation Equipment & Maintenance Activities

Equipment

Maintenance Activities

Transformers

- Oil level & quality checks (DGA).

- Winding resistance tests.

- Cooling system inspection.

Circuit Breakers

- Contact resistance measurement.

- Lubrication of mechanisms.

- SF6 gas pressure checks (if applicable).

Switchgear

- Insulation resistance tests.

- Checking mechanical interlocks.

- Cleaning & tightening connections.

Relays & Protection

- Testing relay settings.

- Secondary injection tests.

- Checking communication with SCADA.

Batteries (DC System)

- Checking voltage & specific gravity.

- Cleaning terminals.

- Load testing.

Earthing/Grounding

- Measuring earth resistance.

- Inspecting connections for corrosion.

Surge Arresters

- Visual inspection for cracks.

- Leakage current measurement.

Busbars & Cables

- Thermal imaging for hotspots.

- Tightening bolted connections.

3. Maintenance Schedule

• Daily/Weekly: Visual inspections, oil level checks, temperature monitoring.

• Monthly: Battery checks, relay testing, infrared scanning.

• Annual: Comprehensive testing (DGA, megger tests, circuit breaker timing tests).

• 5-10 Years: Major overhaul (transformer oil replacement, breaker refurbishment).

4. Safety Precautions

• Follow Lockout-Tagout (LOTO) procedures.

• Use proper PPE (insulated gloves, arc-flash suits).

• Ensure proper grounding before working.

• De-energize equipment where possible.

5. Common Issues & Troubleshooting

• Overheating: Loose connections, overloading (fix by tightening or load balancing).

• Oil Leaks (Transformers): Seal replacement.

• SF6 Gas Leaks (Circuit Breakers): Detection with gas analyzers.

• Corrosion: Apply anti-corrosive coatings.

Conclusion

Effective substation maintenance ensures uninterrupted power supply, safety, and compliancewith regulations. A mix of preventive, predictive, and corrective strategies should be used for optimal performance.

Would you like a detailed checklist for any specific equipment?

The above content is published by demiks, please specify, demiks is a substation equipment manufacturer, specializing in the production of high-voltage tester, transformer tester, circuit breaker test equipment, relay tester, SF6 gas analyser, cable fault tester and other products, if you have power test testing needs, please feel free to contact demiks power science and technology limited company or send an email! Give us: contact@demikspower.com