Arc-flash calculations are based on IEEE 1584 Standard and NFPA-70E regulations. Arc-flash hazard analysis is performed in order to estimate:

The level of Personal Protective Equipment (PPE) at each piece of equipment in the distribution system of any plant; The Arc-Flash boundary distance (AFBD); The Arc-Flash incident energy at typical working distance.

Arc-flash calculations are based on IEEE 1584 Standard and NFPA-70E regulations. When the fault does contain an arc, the heat released can damage equipment and cause personal injury. In the current Arc Heat references, it was found that there is a driving voltage needed to sustain an arc. As an arc becomes longer, the arc voltage increases and becomes greater than the voltage needed to maintain itself. This voltage is approximately 150 V to 180V rms depending on the fault X/R ratio at the study point.

METODOLOGY

The IEEE-1584 provides an estimate of the energy falling on a surface removed from a fault. As more data become available, this test data will be used to refine the Arc Flash program empirical equations. As an option, personal protective equipment (PPE) based on NFPA-70E can be provided.

The arcing current used in EDSA Arc Heat Exposure program is greater than those often associated with the minimum arcing currents used to set PD devices. For Arc Heat exposure the maximum arcing current is of concern.

The heat exposure due to an Electrical Arc can harm, or burn, bare skin or protective clothing.

“The Standard for Electrical Safety Requirements for Employee Workplaces”, (NFPA 70E-2004), provides information on the protective performance of various fabrics, which would limit heat exposure to second-degree burns.

As a general generic procedure, after completing the “Short Circuit Study” the Protective Devices (PD) study is necessary in order to determine the protective devices (PD) tripping times. Once having the PD settings, the Arc Flash program can be used.

A generic procedure is presented based on “Several Case Studies” completed with proper recommendation in order to reduce the arc flash energy and consequently the PPE.

Speaker: Dr. Silvio Darie EDSA Micro Corporation