Applying superimposing principle and Thevenin's theory, as shown in Fig. 2.2, current breaking phenomena can be represented by cancelling current injection. In calculating or considering a TRV, every initial condition in the circuit shall be introduced. In Fig. 2.2, every of the initial conditions can be included in (b) but (b) brings no voltage across the terminals of the circuit-breaker, e.g. the current continues to flow. (c) corresponds to current injection to the dead, i.e. non-initial conditioned, circuit and creating TRV. Care should be taken that this method is only applicable to calculate TRV across terminals. But for intuitive evaluations, this method is useful and effective.
Table 2.1 show some examples and by the combination of a few of them, outlines of TRVs in actual power systems can be imaged.
