Dear Colleagues
The main reason, for writing this newsletter is to inform and educate (both you and me, I might add) and hopefully to ensure that you get value from our newsletters (and naturally open them !).
The one topic, which is still very “hot” is of course Arc Flash protection where we recently ran a well attended and actively debated conference. Evgeniy Mitev and Trung Nguyen (both of Rio) stated that: “An arc flash is the plasma cloud that develops during and following an electrical fault, whereby the insulating properties of air are overcome through rapid ionisation. Most arc power is delivered to, and stored in, the plasma cloud as high-temperature plasma enthalpy. It is characterised by temperatures in excess of 15,000 °C, a cocktail of superheated toxic gases and airborne molten metal from melted conductor and steel, released by the components within an electrical assembly under fault.
As a result of the rapid energy release, a pressure wave also develops of such magnitude such that if contained, may lead to switchboard
structural failure and propel missiles such as panel doors. In the absence of
appropriate pressure relief, arc flash incidents have been known to collapse
entire substation buildings.”
Sesha Prasad (Welcon Technologies) noted the prompt to action here:
“By about 1994, NFPA (in the USA) statistics showed the alarming nature of arc flash hazard. As per the statistics, there were about 1 to 2 fatalities per day in the U.S. in electrical installations. However, there were more than 5 serious burn injuries per day which required extensive burn treatment and skin grafts. These statistics motivated NFPA to initiate research with regard to calculation of incident heat energy due to an arc flash and specifying appropriate Personal Protective Equipment (PPE) to provide arc flash protection.”
There is still considerable ongoing work in research in this area due to disagreement on the current conclusions of the research.
And as my good colleague, Peter Willis (of DIgSILENT Pacific) stated so succinctly in terms of arc flash hazards:
“It can be assumed that all asset owners and operators of electrical infrastructure would want to inform and protect their electrical workers against the many hazards of arc faults including.
•Electric shock.
•Burns Trauma from arc plasma, radiated heat, molten metal.
•Physical Trauma from flying debris and pressure waves.
•Respiratory Trauma from toxic gases.
In order to manage these hazards, they need to be understood by workers so the
appropriate action and countermeasures can be applied.”
Please find at the following link, a download on Arc Flash Protection (please forgive occasional reference to inches and pounds – our next iteration will have both metric and fps).
As engineering professionals, it is our duty to provide suitable protection against industrial hazards. As Sir Francis Bacon remarked 500 years ago:"Man seeketh in society comfort, use and protection."
Yours in engineering learning
Steve
