A new approach in detecting and identifying power quality disturbances is presented. The use of Formal Language Theory, already exploited in other fields, was used to develop an innovative tool to identify patterns in electrical signals. The Concordia transform is applied to the 3-phase electrical system, composing a 2-D signal. The obtained signal is computed with a “healthy” 3-phase composed signal, retrieving new data. A Formal Language based inference algorithm is used to infer a grammar from this new data. Each type of fault has its own grammar, which allows the developed algorithm to easily detect and identify the disturbances.