The investigations of synchronization between the signals are commonly used methodology to assess the condition of transformer insulation during lightning impulse test. Hence, a synchronization measure has so to be defined properly for several non stationary signals through appropriate formulation by using any signal processing, statistical and mathematical analysis. In this paper, the principles of vector space representation of signals, projection theorem, normalization, orthogonal matrix and triangular matrix principles are effectively adopted to derive Joint balancing (Jbalan) vector coefficient for impulse testing of any power and voltage rating and type of transformers. It provides the better way to visualize the mutual computation between several non stationary signals. Jbalan vector coefficient allows the testing engineer to completely describe the mutual synchronization of all possible signals involved during impulse test and it avoid tedious evaluations of integral to take a decision about the transformer through numerical value. To validate the analysis, 5MVA, 7.5MVA and 90/120/150 MVA transformers are used.