Steady-state short-circuit current calculation for internally limited inverter-based distributed generation sources connected as current sources using the sequence method

초록

When inverter-based distributed generation (IBDG) sources with output current limited by an internal current loop control or other control logic are connected to power system networks, they can affect the short-circuit current (SCC) despite their small capacities. Therefore, we derive a method to calculate steady-state SCC from IBDG sources connected to a grid as a current source. To achieve this purpose, this study proposes a method that refers zero- and negative-sequence networks to a positive-sequence network that includes IBDG sources modeled as a current source. This study also defines positive-sequence bus impedance and current injection matrices of the network. Subsequently, this study derives new equations that find the positive-sequence SCC and induced voltages of the network. The proposed method can more accurately calculate SCC that flows from IBDG sources. Thus, accurate SCCs can be used for designing, planning, or maintaining power systems.

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