What are the accident scenarios in a substation?

Leon

07/30/2025

Handling of Minor Action of Transformer Gas Relay

Immediately check and record the protective relay action signals, and report to the dispatcher and station manager.
Closely monitor the transformer’s voltage, current, temperature, oil level, oil color, sound, and cooler operation, and assign personnel to conduct an external inspection of the transformer.
If significant abnormalities are found during the inspection, report to the dispatcher and take the faulty transformer offline. If no obvious fault signs are observed, escalate to higher authorities for gas sampling, analysis, and inspection of secondary circuits.

Handling of Major Action of Transformer Gas Relay

Inspect the relay protection action status, record and reset all signals, and immediately report to the dispatcher and station manager.
For a single operating transformer, request the dispatcher to activate the backup transformer immediately. For parallel-operated transformers, ensure the operating unit does not exceed its load capacity.
Assign personnel to inspect the transformer for deformation, oil spray, oil level, and oil color. Report inspection results to the dispatcher and relevant departments, and conduct gas analysis and secondary circuit inspections.

Handling of Transformer Differential Protection Action

Inspect the transformer body for abnormalities, check porcelain insulators for flashovers or damage, and examine the differential protection zone for short circuits.
If no visible faults are found within the differential protection range, inspect the relay protection system and secondary circuits for faults or two-point grounding in the DC circuit. If no anomalies are detected, attempt to restore power after isolating the load; if unsuccessful, do not re-energize.
If the action is caused by a relay/secondary circuit fault or DC circuit two-point grounding, disable the differential protection, re-energize the transformer, and then address the fault.
If both differential and major gas relay protections are triggered, do not re-energize the transformer without prior internal inspection and testing.

Handling of Transformer Backup Protection Action

Use protective action signals, indicators, and instruments to identify the fault location and power outage scope. Check each branch circuit for protective action signals or tripping flags.
Disconnect all branch switches on the de-energized bus and confirm they are open.
Open line switches with protective actions or tripping flags in the affected circuits.
Inspect the tripped bus and transformer switches for abnormalities.
Check equipment connected to the de-energized bus for faults.
If the fault point is identified, isolate it, restore other unaffected equipment to normal operation, and return the main transformer to service.
Report inspection results to the dispatcher and relevant departments, and maintain proper records.

Handling of Transformer Pressure Relief Protection Action

Check the protection actions and record all triggered signals.
Report the incident to the dispatcher, relevant departments, and leadership.
Conduct a thorough external inspection of the transformer, focusing on whether the pressure relief device has sprayed oil or if the top red button has popped up. Report inspection results to the dispatcher and relevant departments.
If the pressure relief device has sprayed oil and the red button has popped up, this confirms the validity of the pressure relief protection action.

Topics

Power Systems Machines Transformer

Leon

Hello! I'm Leon, with 20 years of extensive experience in the power industry. My expertise spans from power distribution equipment to grid operations and maintenance, grounded in robust hands-on and theoretical knowledge. Currently, I focus on sharing insights into electrical equipment fault diagnosis, demystifying complex technical challenges through accessible explanations. I welcome collaboration with industry peers and enthusiasts to collectively explore the intricacies of the power sector.