ABB Inc: Safety System Uses Light to Prevent Arc Flash

Feb. 14, 2012
Some of the industry segments and applications that can benefit from Arc Guard include substations; critical power facilities such as hospitals and data centers; yachts; cruise and refrigerated container ships; oil rigs; chemical plants; railroad trains and way stations; steel mills; and wind/solar power facilities.
A new-generation Arc Guard Safety System uses light to prevent arc flash injuries. The product is the next generation of the company's proprietary Arc Guard System, which has been protecting electrical equipment for over 35 years. TVOC-2 features numerous upgrades and new functions to provide arc flash protection by detecting faults in low- and medium-voltage switchgear and disconnecting the power provided to the arc within 30 to 50 milliseconds. Without the Arc Guard System, an arc flash will typically trip a circuit breaker in approximately one second, which is enough time for the arc to destroy the switchgear and kill or seriously injure a person. TVOC-2 is now UL listed, and when installed along with the company's Emax circuit breakers, carries a functional safety rating of SIL-2 as certified by TÜV Rheinland. The SIL-2 certification confirms that the TVOC-2 has achieved the standard required to protect both humans and equipment and be used where an engineered safety solution is required.The Arc Guard System uses light as the main condition to instantaneously trip the incoming circuit-breaker. The system acts in three phases:
• Detection - on optical sensor senses when light (an arc flash) is inside the equipment
• Recognition - the arc monitor determines the intensity of the light
• Action - the TVOC-2 sends a signal to trip the breaker(s).
Other feature upgrades include:
• Pre-calibrated optical sensors and fiber optic point sensors
• Hardware-based self monitoring system for critical functions; the software is used only for supervision and information processing
• Wide ranging input voltage ratings (100 to 240 V AC and 100 to 250 V DC)
• Selective tripping of only the affected circuit breaker, not all breakers within a system
• The HMI can be mounted on the TVOC-2 or panel door
• Standard system has 10 sensor inputs, expandable to 30
• User-friendly start-up menu, easy to install
• Mounting options on DIN-Rail or directly on a panel wall.