A 35kV busbar power outage requires immediate fault identification, isolation of the affected section, notification of critical users, and systematic inspection and restoration of service.

Immediate Response and Fault Identification

When a 35kV busbar experiences a fault, the substation and SCADA system typically issue alarms such as “busbar grounding” or arc suppression coil activation. The voltage of the faulted phase drops significantly, while the other phases may rise or remain stable, and outgoing circuits trigger “voltage circuit open” alarms. Operators should immediately notify the central control station to confirm the fault and assess protection status, including 3V₀ voltage, arc suppression coil current, and small-current fault line selector readings .

Isolation and Safety Measures

1. De-energize the affected busbar by opening the relevant circuit breakers and disconnectors. Ensure all equipment not under inspection is isolated.
2. Disable automatic transfer switches (ATS) if present, to prevent the fault from propagating to healthy sections .
3. Notify critical users about the outage before performing any trial switching or load transfers.
4. Patrol the line and substation equipment to visually inspect for arcing, smoke, or other signs of damage .

Fault Location and Load Management

• Use SCADA signals, voltage indicators, and arc suppression coil readings to identify the faulted line or bus segment.
• If a specific line is identified, transfer its load to healthy lines before taking it out of service.
• For substations with multiple bus segments, ensure only the faulted segment is isolated while maintaining service on other segments .

Inspection and Testing

After isolating the fault, perform a thorough inspection of the busbar and associated equipment:

• Check for physical damage, loose bolted connections, and proper grounding .
• Inspect bus conductor support insulators for cracks or broken porcelain.
• Verify internal compartments are clean and free of moisture or dust.
• Conduct partial discharge and ampacity tests to ensure insulation integrity and thermal performance .

Restoration of Service

1. Once the faulted section is repaired or cleared, re-energize the busbar segment gradually, monitoring voltage and current for abnormalities.
2. Confirm SCADA and protection relays are functioning correctly.
3. Restore normal load distribution and notify users of service restoration.

Preventive Measures

• Ensure proper installation and maintenance to prevent insulation breakdown or overheating, as poor conductor contact can trigger busbar faults .
• Regularly test and maintain busbar connections, grounding, and protective relays to minimize outage risks . Following this procedure ensures safe, efficient, and systematic handling of 35kV busbar outages, minimizing equipment damage and service disruption.