The results of the measurements concerning the electric quantities from an auxiliary generator, a three-phase rectifier controlled by thyristors, and a main generator from a power group, performed using an integrated measuring system are presented. The modality to determine the power quality parameters is detailed. The analysis allows the detection of possible undesired distorting regimes, with serious drawbacks over the operation of a power group. The correct analysis/interpretation of the recorded data may be used to a real-time diagnosis/removing of undesired regimes. The coordinated recording may also detect the power flow (auxiliary <-> main) generators through the rectifier, when the protection measures are compulsory. A new approach considering the correct techniques for testing and correct handling of the powers/energies is discussed. New research directions are considered in order to perform a correct handling and proper taxing for power and energy sources in a power system.