Research Article
Nikolovski et al., J Ind Electron Appl 2017, 1:1
Journal of Industrial
Electronics & Applications
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Arc Flash Analysis and
Techniques for Hazard
Reduction Using Smart
Protective Devices
Srete Nikolovski*, Dragan Mlakic and Emir Alibasic
Abstract
This paper presents an arc fash risk assessment taking care of
the protection device coordination procedure in order to reduce
incident arc fash energy at low voltage busbars in a biomass power
plant. The mitigations were measured and presented to reduce
incident arc fash energy using the appropriate smart protection
device software. A short circuit analysis is performed to calculate
the values of short circuit currents and compute arc fash energy
dissipated at busbars at low voltage busbars in the biomass power
plant. An arc fash can cause damages to electrical equipment and
personnel. In this paper, three main techniques were considered,
namely arc fash prevention, prediction and monitoring, detection
and reduction using a smart arc fash module and proper protection
coordination software. A practical sample case is presented for low
voltage busbars in one biomass power plant in Croatia.
Keywords
Arc fash; Short circuit; Mitigation measures; Protection devices;
Time current coordination; Low voltage busbars; Biomass power
plant
Introduction
Our increased dependence on renewable energy sources and a
need to improve the reliability of distribution networks has resulted
in a lower tolerance of any power outage and higher security for
personnel and equipment. Consequently, it has created a need
for electrical workers to perform maintenance work on energized
electrical equipment (live working conditions). In addition to the
electrical shock hazard that results from a direct contact of live
conductors with a body, workers are also exposed to the injury risk
due to accidental initiation of electric arcs. Arc fash injuries can occur
without any direct contact with energized parts. Tis arc fash hazard,
due to arcing faults, has existed from the beginning of the electric
power industry but it has only recently been addressed as a specifc
problem and hazard in electrical safety programs and national safety
codes.
Electrical environment is changing fast and the power industry is
considering innovations in the electrical systems designs, equipment
and protection aiming to limit the arc fash hazard as it is detrimental
*Corresponding author: Srete Nikolovski, Department of Power Engineering,
University of Osijek, Osijek, Croatia; Tel: +3850912246005; Fax: 385 31 224
6005; E-mail: srete.nikolovski@etfos.hr
Received: December 05, 2017 Accepted: December 10, 2017 Published:
December 26, 2017
to the worker safety. Tis raises new issues in the power system design,
analysis, and computation and simulations [1].
Protection devices and new techniques for the arc fash detection
and fast elimination are essential for the electric power industry
analysis in order to avoid damages due to an arc fash produced by
short circuit currents [2]. Arc fash hazards can result from many
factors, including dropped tools, accidental contact with electrical
systems, build up of conductive dust, corrosion and inadequate work
procedures. An arc is produced by a fow of electric current through
ionized air afer an initial fashover or short circuit resulting in ash
that can cause signifcant heating and burn injuries.
An arc fash is very dangerous because it produces dangerous
levels of radiant heat energy capable of causing severe burns and
ignition of clothing, which can result in treatment requiring years of
skin grafing, rehabilitation and even death. Spray droplets of molten
metal, with the explosion distributing the molten metal and shrapnel
produced by the arc can be expanded to a large area. Produced blast
pressure waves can blow workers across the room and knocked them
of ladders. Arc fash can result in personnel deafness [3].
Te arc fash analysis and hazard assessment are diferently
normed in the USA and EU countries. In the USA, IEEE 1584-2002
entitled “IEEE Guide for Performing Arc-Flash Hazard Calculations”
is standard. It provides a methodology for calculating prospective arc
fash hazards [4]. Based on the test data, the IEEE 1584 committee
defned empirical equations to calculate arc fash incident energy for
AC systems. Although OSHA-Occupational Safety and Health Act of
1970 has not specially addressed the arc fash, the existing and new
provisions impact are as addressed:
OSHA 1910.132 (d), and 1926.28 (a). OSHA considers NFPA 70E
a consensus industry standard for assessing arc fash standards [5].
An employer is responsible to:
1) assess the hazards in the work place;
2) select, have and use the correct PPE;
3) document the assess distance.
OSHA considers arc fash assessments that follow NFPA 70E.
Tey have to be in line with OSHA requirements and protect workers
from electrical safety hazards [6,7].
In the EU, IEC standard does not pay a special attention to the
arc fash energy calculation but it has a standard for PPE-personnel
protection equipment for arc fash protection equipment testing. IEC
61482-1 and the identical EN 61482-1 are split into two parts which
cover the methods for testing of clothing fabrics and garments that
are designed to protect against arc fashes.
IEC 61482-1-2 and the identical E 61482-1-2, which now
supersedes ENV 50354, have become known as the “box test”. Tere
are two test method versions - the “material box test”, which includes
the heat transfer measurements, stoll curve diferential analysis, and
the “garment box test”, which requires only a visual assessment of the
garment performance [8].
Te box-test standard defnes two testing conditions, namely
Class 1 and Class 2: