Fast Linear Power Flow Algorithm for the Study of Steady-State Performance of DC Grid

As the penetration of renewable resources and direct current (dc) nature loads increase, dc grids are getting more attraction in the future smart grid architecture. However, how to obtain the steady-state performance of a dc grid under different disturbances fast is still a challenge. To solve this problem, this study aims to derive a fast linear power flow (LPF) model instead of nonlinear algorithms for a dc grid. After analyzing the control characteristics of different converters, a generalized control equation for each dc bus is derived. Then, on the basis of the generalized control and network equations, an LPF algorithm is proposed for the strict requirement of the dc voltage deviation. Error analysis is performed on the proposed LPF algorithm, and a correction method for the LPF algorithm is developed. Case studies based on Cigre B4 DC grid test system are conducted to validate the effectiveness of the proposed LPF. Compared with the Newton-Raphson algorithm, the proposed LPF not only improves the calculating speed greatly but also preserves the accuracy of the power flow of the dc grid.