Fire Safety Measures for Electrical Facilities: Key steps for substations and power lines, including firefighting, electrocution risks, and emergency response.

in substations present dangers such as electrocution, toxic gases from burning insulation, and explosions due to vaporized insulating oil. Below is a detailed guide on fire safety measures for substations and cubicles.

Types of Substations

Ultra-High Voltage Substations

• Description: Handle voltages of 500,000 volts and 275,000 volts.
• Role: Transform and distribute electricity from power plants to various regions or high-voltage substations.

Primary and Secondary Substations

• Description: Intermediate substations between power plants, ultra-high voltage substations, and distribution substations.
• Role: Distribute electricity to different areas and large industrial facilities.

Distribution Substations

• Description: Reduce voltage to 6,600 volts and deliver electricity to homes through distribution lines.
• Voltage Flow:
  • From power plants: 500,000 – 275,000 volts
  • From ultra-high voltage substations: 154,000 volts
  • From primary substations: 77,000 volts
  • From secondary substations: 33,000 volts
  • From distribution substations: 6,600 volts
  • From pole transformers to homes: 100 – 200 volts

Substation Types by Structure

Outdoor Substations

• Description: Main equipment like transformers and circuit breakers are installed outside; control devices are inside buildings.
• Common Use: Most substations are outdoor type.

Indoor Substations

• Description: All main transformers and control equipment are installed inside buildings.
• Advantages: Better environmental integration and smaller footprint compared to outdoor substations.

Underground Substations

• Description: Main equipment is installed underground, often under buildings or parks in urban areas.
• Advantages: Maximizes land use in densely populated areas.

Firefighting Procedures

Initial Response

1. Assessment:
   • Determine if the fire is in an electrical facility and request an early shutdown of power to prevent electrocution.
   • Prepare insulating rubber gloves and other protective gear.
2. On Arrival:
   • Wear protective gear but do not solely rely on it for safety.
   • Do not enter the site if power shutdown is not confirmed.

Entry Procedures

1. Entering Enclosed Areas:
   • Be cautious when opening doors to cubicle-type distribution boxes or electrical rooms to prevent backdrafts.
   • Even after power is cut, there may be residual electricity. Confirm safety with the electric utility before entry.
2. Handling Equipment:
   • Be careful of sparks when using equipment like engine cutters.
3. Toxic Gases:
   • Always wear breathing apparatus due to the release of toxic gases from burning PVC insulation. Ensure proper ventilation.
4. Watch Your Step:
   • Insulating oil may leak, making surfaces slippery. Pay attention to your footing.

Water Use

1. Water Use Guidelines:
   • Only use water after power is confirmed shut off. If necessary, use water in a mist pattern to minimize risk.
   • Prefer using powder extinguishers for small fires.
   • Ensure no conductive paths are created by water to avoid electrocution.
2. Safety Precautions:
   • Establish grounding for vehicles and nozzles.
   • Avoid direct water spray on pole-mounted transformers due to the risk of falling burning oil.

Electrocution Hazards

1. Electrocution Risks:
   • The danger of electrocution is related to the current (amperes) rather than voltage.
   • As little as 0.1 amps can be fatal if it disrupts heart function.
2. Impact of Electric Current:
   • 1mA: Slight tingling.
   • 5mA: Pain but not dangerous.
   • 10mA: Skin burns.
   • 20mA: Muscle spasms.
   • 50mA: Breathing and heart can stop.
   • 100mA: High risk of death.

Emergency Medical Response

1. Remove Electrical Hazard:
   • Ensure power is cut off before treating the victim. Call the utility company if needed.
2. Medical Actions:
   • Cardiac Arrest: Perform CPR and use an AED.
   • Respiratory Arrest: Provide artificial respiration.
   • Burns: Treat for electrical burns, which might be deep and serious.
   • Shock: Lay the victim down, monitor vital signs, and keep them warm.

Guidelines for Emergency Responders

1. Fallen Power Lines:
   • Stay at least 10 meters away and avoid touching downed wires.
   • Use shuffle steps if necessary to move in the area.
2. Rescue from Vehicles in Contact with Power Lines:
   • Evaluate the scene from a safe distance.
   • Direct occupants to stay inside the vehicle until the utility company cuts the power.
   • If the vehicle is on fire, instruct occupants to jump clear of the vehicle without touching it and shuffle away.

Fire Extinguishing Methods

1. Water Use:
   • Use water spray from a safe distance. Maintain a pressure of 700 Kpa and a spray angle of 30 degrees.
   • Never use direct streams of water on live electrical fires.
2. Arc-Over Hazards:
   • High-voltage lines can cause arcing during intense fires, creating risks of electrocution.
   • Establish safe distances based on voltage levels:
     • 115,000 volts: 10 meters.
     • 230,000 volts: 15 meters.
     • 500,000 volts: 32 meters.

Trees Contacting Power Lines

1. Evaluation:
   • Assess from a safe distance if trees are touching power lines.
   • Contact the utility company to address the issue.
2. Safety Zones:
   • Maintain safety zones based on voltage levels as listed above.

Understanding and following these guidelines ensures safe and effective response to fires in electrical facilities. Always prioritize safety and confirm power shutdown before proceeding with firefighting or rescue operations.

Reference page: “Key fire characteristics: combustion elements, smoke risks, toxic gases, and safe firefighting techniques.”

References　National Fire Protection Association (NFPA)

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