3 Safety Measures to Mitigate Substation Risks
Any type of utility work can present a number of potentially fatal hazards, from arc blasts and flashes to extreme temperatures that can cause the human body to overheat or become hypothermic. And it’s not just severe hazards that can lead to injury or death – even the slightest negligence can bring about circumstances in which workers can get hurt. Regardless of the job or work environment, careful analysis of all risk factors is a must, along with initial and ongoing training and communication. In this month’s Tailgate, we’re going to take a look at three important safety measures that can minimize risk when working in a live substation.
1. Personal Protective Equipment
PPE must be worn that is appropriate for the potential hazards that may be encountered. Work areas must be assessed by a person qualified to determine what PPE is required for the hazards involved. PPE may not always be the first choice for protection. If a hazard can be avoided by re-engineering or changing the work plan or procedures, choose that option first. Good PPE procedures use PPE as a last resort to mitigate hazards that cannot be controlled through procedures or engineering changes. PPE for substation work might include arc-rated/flame-resistant clothing, high-visibility vests appropriately rated for the electrical environment, head protection, safety glasses with side shields, fall protection and insulated gloves.
2. Grounding
Properly installed ground systems in substations provide fast clearing of electrical faults and ensure that equipment that is accessible to workers is not energized. If you can’t see that an apparatus or structure is grounded to the substation grid, you must handle it with the appropriately rated rubber gloves until you can determine that it is free of hazardous voltage. When grounding bus or equipment for safety, grounds must be arranged in such a manner that no one can be exposed to a hazardous difference in potential. Grounding that is arranged in such a way is one of the most effective means of protection from electrical hazards. More specifically, when working in close proximity to both overhead and underground energized electrical equipment and conductors, effective grounding of equipment protects employees from the hazards of induced voltages that can accumulate on equipment. There are a variety of grounding and bonding procedures that can be used to protect individuals from potential shock. Planning for grounding and installing grounds must be done by a qualified individual. The OSHA standard requires that grounds be installed grounded end first; then, using a hot stick, install the ground onto the device’s grounding stud or bus.
Be aware that ground clamps, ferrules and cable can degrade, making them less effective. It is essential to test those items on a regular basis. For grounds to be effective, they must be:
- A low-resistance path to earth.
- Brushed-clean, tight connections.
- Connected to proper points determined by a qualified individual.
- Of adequate current-carrying capacity for the grounding equipment.
3. Planning and Barricades
Movement of people and equipment within a substation often is the cause of disasters. Trucks – especially those pulling trailers – routinely strike columns and other structures, many times resulting in their collapse. That’s because substation yards lack curbs and road markings that drivers use to judge turning radius and maneuvering space.
Plan ahead. Determine the best route to travel by planning trips through the substation yard for efficiency, limiting the need to move equipment. Use observers when backing as well as when moving forward while pulling trailers. Before crews start work, determine where workers need to be as well as where they should not be. Communicate the movement plans clearly and hold employees accountable. Evaluate risks in those work areas and communicate those to crew members as well. Use yellow barricade tape to designate work areas and red barricade tape to designate hazardous or no-go areas.
Conclusion
While these three measures won’t address all of the hazards that may be lurking in a substation, using them effectively will help to protect personnel from some of the greatest risks to their health and safety.
About the Authors: Ryan Stephens, AEP, is a safety engineer at Aldridge Electric. He received a bachelor’s degree in environmental health sciences from Purdue University.
Amber Travis, GSP, is a safety engineer for Aldridge Electric. She earned a bachelor’s degree in safety management from Slippery Rock University.