Analysis of zero-sequence current injection response in compensated distribution networks

The zero-sequence current injection is an essential method that is applied to various complex applications in compensated distribution networks. This paper introduces the necessary current injection theory, including the equations that describe the system’s response to current injection and parameters affecting it. The parameters are especially considered in terms of basic parameters of compensated networks including system damping, detuning, and asymmetry, so that the outcome of the current injection can be easily understood intuitively. This allows easy analysis of current injection response using the basic earth fault parameters. The influence of current injection frequency is further described, and concept of resonant frequency is introduced, illustrating its advantages. Finally, PSCAD simulations are used to visualize and verify the validity of the presented current injection theory.