ABB’s TVOC-2 arc guard system instantaneously enabled a global industrial automation company to avert a possible fire that could have threatened its entire plant after an arcing event in a motor control center
While ABB’s wide range of electrification systems enables manufacturers to operate more efficiently with more reliable power, one system in particular has also helped save the lives of employees. TVOC-2 arc guardTM from ABB is an optical detection system that, together with an external breaker, can limit the damage to personnel and equipment in case of an arcing accident in a cable or circuit breaker. This potentially dangerous occurrence can ignite the wiring within an electrical panel and may continue burning as current flows from the upstream power supply.
ABB channel partner PSY International (formerly PSY Systems) discovered the true effectiveness of arc guard during a recent event at a customer’s location. PSY International is renowned for its work in industrial automation and process control for specialized applications across many industries. Based in Johannesburg, PSY provides services throughout Africa, the United Kingdom, Australia and Scandinavia. Its client base includes businesses in sectors such as iron and steel, food and beverage, milling and sugar, manufacturing, chemical, water and waste.
Recently, just two weeks after installing a motor control center (MCC) and arc guard at a customer location, engineers there encountered an unexpected cable arc. ‘’This uncontrolled event could have destroyed the panel and, even more disastrously, could have put the entire plant at risk of an electrical fire,’’ said Elvis Khumalo, Product Marketing Specialist for ABB’s low-voltage products in South Africa. ‘’Even if the damage was confined to the MCC itself, the complete system would have had to be shut down until it could be replaced, a process that could take up to six weeks and generate significant costs for the customer in terms of downtime, as well as equipment repair and replacement.’’
Fortunately, ABB’s technology automatically prevented any of these devastating consequences from developing. The arc guard system shut off the main power supply within 50 milliseconds, preventing any damage to the panel. Arc guard was able to prevent a disaster because it relies on unshielded fiber-optic sensors—16 of them in this instance— to detect the intense light created by a developing arc anywhere in the panel. Once an imminent arc was spotted by arc guard’s sensors, the unit’s hardwired shunt trip provided millisecond reaction time to shut down the system.
The ABB arc guard incorporates a central unit that can be used either in a standalone configuration or linked to other main and extension modules. Two high-speed, insulated-gate bipolar transistor outputs signal the circuit breaker to trip. The system also includes a heavy-duty relay output that can be used either for circuit breaker failure protection or as an alarm output.
Arc guard stopped the emerging arcing incident at PSY’s customer site before it could cause any damage. “It was fortunate for the client to have the arc guard system installed,” said Paul Young, managing director of PSY International. “This particular incident could have resulted in serious injuries or even death from the hazardous arc. Additionally, it could have cost the client R500,000 (rands) for a new MCC panel, as well as losses in production due to shut down. With arc guard in place, workers remained safe and all that was required was a cleanup of the panel.”
The success of arc guard in this incident reinforces PSY International’s commitment to ABB technology as it provides process control and machine safety solutions for a broad spectrum of industries, building on advanced systems from ABB.
“Safety always comes first at ABB,” continued Khumalo, “and arc guard is designed to help manufacturers carry forward their own dedication to safety in their plants and in their customers’ facilities.”
