# A Multi-Period Optimal Reactive Power Dispatch Approach Considering Multiple Operative Goals
## 4 Conclusions  
This paper presented a novel approach to the MP-ORPD problem. A new formulation considering three operative goals was presented and implemented. The first goal under consideration was to maintain adequate voltage profiles in all power systems using a reduced set of buses (pilot nodes), whereby the values of the voltage set points were adjusted dynamically, changing every period according to load conditions. The second goal was to avoid excessive maneuvers on shunt devices, since a large number of these lead to lower life expectancy for the devices and more maintenance under real-life circumstances. The third goal was to maintain the dynamic reactive power reserves of the generators, guaranteeing a fast response to control voltages during the contingency scenario. The main feature of the proposed MP-ORPD model lies in its applicability in real power systems, since it does not follow conventional objective functions, such as power loss reduction; instead, it guarantees operative feasibility throughout a given time horizon, while minimizing the number of maneuvers on reactive power devices. Several tests carried out on the IEEE 57-bus and 118-bus test systems proved the effectiveness and applicability of the proposed approach. It was found that the weighting method allows the priority of the objectives to be adjusted, providing flexibility to meet the needs of each system under analysis. The decision to choose a set of pilot nodes significantly improved the computation \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline  & \begin{tabular}{c} **Case** \\ **Base** \\ \end{tabular} & **TQG** & **TQD** & **TVD** & \begin{tabular}{c} **TQG+** \\ **TQD** \\ \end{tabular} & \begin{tabular}{c} **TQG+** \\ **TVD** \\ \end{tabular} & \
\begin{tabular}{c} **TVD+** \\ **TQD** \\ \end{tabular} &
\begin{tabular}{c} **TQG+** \\ **TVD+** \\ **TQD** \\ \end{tabular} \\ \hline \(\sum u_{il}^{\top}\) & 0 & 85 & 20 & 51 & 72 & 71 & 54 & 78 \\ \(\sum u_{il}^{\top}\) & 0 & 13 & 0 & 20 & 14 & 19 & 0 & 17 \\ \(\sqrt{TQG}\) & 33037 & 4493 & 35997 & 36509 & 4494 & 10337 & 37000 & 10341 \\ \(\sqrt{TVD}\) & 18.22 & 20.98 & 7.37 & 8E-06 & 20.98 & 0.66 & 4E-12 & 0.66 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Sensibility of the objective function components for IEEE 118-bus system. \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline  & \begin{tabular}{c} **Case** \\ **Base** \\ \end{tabular} & **TQG** & **TQD** & **TVD** & \begin{tabular}{c} **TQG+** \\ **TQD** \\ \end{tabular} & \begin{tabular}{c} **TQD+** \\ **TVD** \\ \end{tabular} & \
\begin{tabular}{c} **TVD+** \\ **TQD** \\ \end{tabular} &
\begin{tabular}{c} **TQD+** \\ **TQD** \\ \end{tabular} \\ \hline \(\sum u_{il}^{\top}\) & 0 & 117 & 51 & 141 & 118 & 118 & 135 & 118 \\ \(\sum u_{il}^{\top}\) & 0 & 0 & 0 & 4 & 0 & 1 & 0 & 1 \\ \(\sqrt{TQG}\) & 4757 & 3928 & 4588 & 6965 & 3928 & 5101 & 7080 & 5101 \\ \(\sqrt{TVD}\) & 10.56 & 29.94 & 10.97 & 0.18 & 29.9 & 1.69 & 0.2 & 1.69 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Sensibility of the objective function components for the IEEE 57-bus system. times with respect to the optimization of the system nodes. The computation times for the optimization process were 17.5 and 100 s for IEEE 57-bus and 118-bus test systems, respectively, showing that the model can be used in coordinated voltage control strategies for day-ahead and very short-term operation planning. Although dynamic reactive power reserves are considered, voltage stability issues are not explicitly integrated in the model. This could be a topic of future research, along with the implementation of a multi-area MP-ORPD model and parallelization process in order to reduce computation times.