ABB, a power and automation technology group, has won the approval of DNV GL – the world’s largest ship and offshore type approval organization – for its REA 10 arc flash monitoring systems for installation on board ship and offshore units. Designed to protect new and existing medium and low voltage electrical switchgear, the REA modules use fibre optic detectors to monitor and protect against electrical arcs.
Arc flash is particularly important in the oil and gas sector, where growing demand for power is twinned with the highest health and safety standards. It is not a new phenomenon but interest and concern about the dangers associated with arc flash events have increased dramatically in recent years in response to new guidelines and standards put forward by various international trade and safety bodies such as the Institute of Electrical and Electronic Engineers (IEEE), the US Occupational Safety and Health Administration (OSHA) and Lloyds Register.
Reducing the arcing time through faster detection is the most practical means of lowering incident energy levels and improving workplace safety. The energy released in an arc flash incident is directly proportional to arcing time and even a few milliseconds improvement may shift hazard levels and PPE requirements to lower categories. For arcing times of 40 ms or less there is typically no personal injury or switchgear damage, while arcing times of 500 ms or more will cause serious personal injury and major damage to switchgear.
ABB’s REA arc flash protection relays use a long unclad fibre-optic sensor that can absorb the light from an arc flash throughout its length. This offers the benefits of simpler installation and better coverage than individual light sensors, as well as the ability to retrofit in existing installations and self-checking. In normal operation, both intense light and over-current must be present simultaneously for tripping to occur, with the relay signaling the circuit to break within a miniscule 2.5 ms.
Offshore operators are now required to carry out studies to identify arc flash risks and put in place measures to protect operatives and equipment, with the approach being to supply and renew specialist PPE on an annual basis. Operators could instead install ABB’s REA arc flash detection system, which eliminates a significant portion of the risk by reducing tripping times.
Ian Hodkinson, head of ABB’s Distribution Automation business in the UK said: “Winning type approval from DNV is a major endorsement for ABB’s REA Arc Flash Detection System. A typical substation might only experience a single incidence of arc flash protection in its lifetime but the impact of such an incident is significant in terms of risk to life and limb, serious damage to electrical hardware and lost production time.”
To achieve DNV’s approval, ABB’s equipment was type tested by DNV in accordance with the standard set out by IEC 60255 and environmental tests were carried out according to DNV’s Standard for Certification (low temperature, dry heat, damp heat, salt mist and vibration) in accordance with the EMC directive and IEC 60255 series.
