ABB’s TXplore robot redefines transformer inspection
Despite the use of non-invasive condition monitoring techniques to determine possible faults and avoid adverse failures in oil immersed transformers, there are routine and emergency situations that require costly internal inspections with major risk to both transformer structure and human inspectors. Nowadays, utilities perform internal visual inspections following lightning strikes and when there is the need to isolate the exact location or severity of a fault, multiple faults or complete a planned repair. In cases such as these, the mineral oil must be removed and stored so that a highly skilled transformer inspector can enter the hazardous enclosed space of the transformer tank, risking damage to both the inspector and transformer. The inspection process also requires medical teams and other expert personnel to be present. Commonly, during inspections, transformer downtime is three days – seen overall, internal human inspection has high human and capital costs. With over 200,000 projects completed, ABB is a global leader in the production, monitoring and maintenance of transformers. Much thought has been devoted to internal inspections of these devices with the aim of lowering capital costs, improving the effectiveness of inspection data, lowering the safety risk to humans and transformer assets and reducing downtime. In late 2012, ABB proposed a concept to develop a remotely driven robotic system to operate reliably and effectively within the toxic and fragile environment of a transformer unit and eliminate the need for human inspection. To be a viable option for utilities, the remotely driven robotic system must inspect the transformer, navigate effectively and maintain the integrity of both the transformer and its oil. High quality visual images and data must be collected and transmitted to external systems for evaluation. A multi-disciplinary team of scientists and engineers from ABB was formed to design such a system. The result of their efforts is the submersible transformer inspection robot now known as TXplore.
Technical development and validation of TXplore
Power transformers are expensive, yet critical machines that are designed and manufactured using complex engineering and construction methods to deal with stressors encountered during their lifetime – e.g., overvoltage, short-circuit currents, high temperature of windings and contaminants. The circulation of insulating oil allows heat to be removed from the windings and is crucial to the health of the transformer. Any object, including a robot, which enters the transformer must preserve the integrity of the oil. For this reason, ABB designed the entirely new TXplore system.