To speed up the algorithm of Gauss-Seidel load flow, an accelerating factor \((\alpha)\) is usually used. Which one of the following relations presents that?

1) \(\mathbf{V}_{\mathbf{i}, \mathbf{A c c}}^{(\mathbf{k}+\mathbf{1})}=\mathbf{V}_{\mathbf{i}}^{(\mathbf{k})}+\alpha \Delta \mathbf{V}_{\mathbf{i}}^{(\mathbf{k}+\mathbf{1})}\)

2) \(\mathbf{V}_{\mathbf{i}, \mathbf{A c c}}^{(\mathbf{k}+\mathbf{1})}=\alpha \mathbf{V}_{\mathbf{i}}^{(\mathbf{k})}+\Delta \mathbf{V}_{\mathbf{i}}^{(\mathbf{k}+\mathbf{1})}\)

3) \(\mathbf{V}_{\mathbf{i}, \mathbf{A c c}}^{(\mathbf{k}+\mathbf{1})}=\alpha\left(\mathbf{V}_{\mathbf{i}}^{(\mathbf{k}+\mathbf{1})}-\mathbf{V}_{\mathbf{i}}^{(\mathbf{k})}ight)\)

4) \(\mathbf{V}_{\mathbf{i}, \mathbf{A c c}}^{(\mathbf{k}+\mathbf{1})}=\mathbf{V}_{\mathbf{i}}^{(\mathbf{k}+\mathbf{1})}+\alpha \Delta \mathbf{V}_{\mathbf{i}}^{(\mathbf{k})}\)