Arc Flash: Mitigate the Risks

Workplace safety should always be at the top of the priority list, with that being said one of the biggest hazards in any electrical distribution systems is the risk of arc flashes or arc faults. Simply put, arc flash is a phenomenon where an electric current leaves its intended path and travels through the air from one conductor to another, or to ground. The result of this is often violent and catastrophic for both personnel and equipment. If a person is in close proximity to such event, serious injury or death will result.

Leading causes of arc flash:

• Dust
  
  
• Dropping tools
  
  
• Accidental Touching
  
  
• Condensation
  
  
• Mechanical Failure
  
  
• Corrosion
  
  
• Faulty Installation
  
  

Factors that determine the severity of the arc flash include the proximity of the worker to the hazard, temperature, and length of time for circuit to break.

Unfortunately when a human is exposed to an arc flash (because of the instantaneously violent discharge of large amounts of electricity) the results are very often serious or fatal. The worker is unlikely to live the same quality of life they once enjoyed prior to such event and the medical expenses are monumental often costing over $1M in a lot of cases.

Typical injuries caused by arc flash:

• Severe burns
  
  
• Fire
  
  
• Flying debris (usually in a molten metal state)
  
  
• Blast pressure (up to 2,000 lbs. / sq.ft)  
  
  
• Hearing loss (140 dB / Gunshot)
  
  
• Extreme heat (up to 35,000 Degrees F)
  
  

Evaluate the risk of arc faults in your power distribution installation: It can save lives

A vast majority of the arc faults are caused by incorrect human actions or by aging network equipment. One way of reducing the impacts of arc faults and associated risks is to focus investments on technological solutions that recognize, evaluate and mitigate these deadly and costly risks.

Solutions:

Arc fault detection system REA (Relays) – ABB offers a fast and selective arc fault mitigation for air-insulated low and medium voltage switchgear is a natural component of modern switchgear panels and a safety and security retrofit for older switchgear panels to protect human lives and prevent or reduce material damage.

The function of the REA arc fault protection system is based on detecting the intense light of an arc flash (using fiber optic sensors) alone or on a detection of arc flash light and simultaneous phase or neutral overcurrent. On detection of an arc fault, the REA arc fault protection system delivers trip commands in less than 2.5 ms (speed of light) to all circuit breakers that feed the fault zone. Furthermore, the operation indicators of the REA arc fault protection system guide the maintenance staff to quickly localize the fault zone. This relay system reduces arc energy by 80% thus limiting personal and property damage.

Ultra-Fast Grounding (Earthing) Switch UFES - active internal arc protection for switchgear. Innovative arc flash mitigation with fiber optics and current detection in less than 4 ms: the highest possible level of arc flash protection for personnel and equipment.

UFESTM is a combination of devices consisting of an electronic unit and the corresponding primary switching elements which initiate a 3-phase short-circuit to earth in the event of a fault. The extremely short switching time of the primary switching element in conjunction with the rapid and reliable detection of the fault, ensures that an arc fault is extinguished almost immediately after it arises (Extinguishing time < 4 ms after detection).

SafeGear and SafeGear HD arc resistant switchgear - SafeGear, rated up to and including 50kA, and SafeGear HD, rated for 63kA applications, not only meet the conventional standards for metal-clad switchgear, but goes beyond the metal-clad standards to provide the added protection of arc-resistant construction. The arc-resistant design reduces life cycle costs through equipment protection, and improves safety for operations and maintenance personnel.

During an arc fault, expanding hot gases are carefully routed through a system of vents and flaps, through the roof and ducted safely away from personnel at the front, rear, and sides of the switchgear. Doors and panels are reinforced and sealed to withstand the temporary pressure surge until relief vents and flaps operate. Damage is contained in the compartment of the arc fault, rather than spreading to adjacent compartments. Ultimately, equipment damage is reduced, equipment reliability is increased, and tragic injuries to employees are prevented.

PulserPlus.Net™ – REDUCES RISK OF ARC FLASH HAZARDS BY 98%! It is accepted in the electrical industry that 98% of all electrical system failures begin as ground faults. High Resistance Grounding limits the fault current so that ground faults do not develop into a more serious equipment problem or potential safety problem.

• There is no need to immediately trip the system, allowing continued process operation and orderly management of downtime.
  
  
• Thermal damage to equipment is dramatically limited due to the low fault current.
  
  
• Overall plant safety is improved since the Arc Flash Hazard is reduced by 98 percent.
  
  
• Ground faults are easy to locate and repair, saving maintenance time and money.
  
  

The Post Glover PULSERPLUS.NET is an excellent choice for grounding applications in process industries, steel mills, pulp and paper mills, power distributors, mining operations, hospitals, and 24/7 data centers.