# A Short-Circuit Current Calculation Model for Renewable Power Plants Considering Internal Topology
## 5 Conclusions  
Improved accuracy in fault detection and SCC estimation enhances the design, protection, and operation of renewable power plants. It allows for more reliable protection systems, reduced costs, and more efficient integration with the grid. These benefits not only improve the safety and economic performance of the wind farm but also contribute to a more resilient and stable power grid, which is critical as renewable energy becomes an increasingly larger part of global electricity generation. In the design of wind farm electrical protection systems, the accurate calculation of short-circuit currents is essential for the proper selection and sizing of protective devices. For instance, in a wind farm substation, circuit breakers are required to protect the electrical network connected to multiple wind turbines. If the short-circuit current is underestimated, engineers may inadvertently \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{\(\gamma\)} & \multirow{2}{*}{\begin{tabular}{c} **Short Circuit** \\ **Impedance/\(\Omega\)** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} **PCC Voltage** \\ **Simulated** \\ **Value/v.u.** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} **Simulated** \\ **Value/kA** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} **Single-Machine** \\ **Multiplication** \\ **Calculation** \\ **Value/kA** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} **Single-Machine** \\ **Multiplication** \\ **Calculation** \\ **Error/\%** \\ \end{tabular} } & \multirow{2}{*}{\
\begin{tabular}{c} **The** \\ **Method** \\ **Calculation** \\ **Value/kA** \\ \end{tabular} } & \multirow{2}{*}{
\begin{tabular}{c} **The** \\ **Proposed** \\ **Method** \\ **Relative** \\ **Value/kA** \\ \end{tabular} } \\ \hline \multirow{2}{*}{0.25} & 1 & 0.2086 & 0.4059 & 0.4223 & 4.04 & 0.4055 & \(-0.11\) \\  & 2 & 0.3451 & 0.3511 & 0.3583 & 2.03 & 0.3482 & \(-0.84\) \\  & 3 & 0.4552 & 0.2978 & 0.3098 & 4.01 & 0.3022 & 1.46 \\ \hline \multirow{2}{*}{0.50} & 1 & 0.2808 & 0.3797 & 0.3878 & 2.12 & 0.3762 & \(-0.92\) \\  & 2 & 0.4561 & 0.2976 & 0.3095 & 4.02 & 0.3019 & 1.47 \\  & 3 & 0.5790 & 0.2478 & 0.2605 & 5.11 & 0.2556 & 3.16 \\ \hline \multirow{2}{*}{0.75} & 1 & 0.4570 & 0.2975 & 0.3092 & 3.95 & 0.3017 & 1.40 \\  & 2 & 0.6651 & 0.2264 & 0.2309 & 1.97 & 0.2279 & 0.63 \\ \cline{1-1}  & 3 & 0.7723 & 0.2028 & 0.2030 & 0.10 & 0.2019 & \(-0.46\) \\ \hline \hline \end{tabular}
\end{table} 
Table 3: The short-circuit current of the wind farm. choose circuit breakers with insufficient interrupting capacity. This miscalculation could result in delayed fault clearance, allowing fault conditions to persist longer, potentially causing significant damage to sensitive equipment, such as turbines or transformers, or even leading to cascading failures within the grid. Conversely, by employing accurate short-circuit current calculations, engineers can ensure that circuit breakers with appropriately rated interrupting capacities are selected. This enables timely fault detection and isolation, thereby enhancing system reliability and minimizing the risk of extensive equipment damage and grid instability. Such precision in short-circuit current estimation thus directly contributes to both the operational safety and cost-efficiency of the wind farm. An inaccurate short-circuit current estimate may lead to over-protection, resulting in frequent and unnecessary disconnections of renewable energy sources during transient conditions. By using more accurate calculations, engineers can reduce such occurrences, leading to less frequent power interruptions and better overall plant efficiency, which in turn improves economic returns by ensuring that the plant operates closer to its full potential. According to the control strategy of the N-SMSs, the analytical expression of short-circuit current under LVRT has been derived in this paper.