## 6 Congestion Management
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Reference** & **FACTS Devices** & \
\begin{tabular}{c} **Methods/** \\ **Optimization** \\ **Algorithm** \\ \end{tabular} & **Findings** &
\begin{tabular}{c} **Limitations/Drawbacks/** \\ **Future Directions** \\ \end{tabular} \\ \hline
[204] & TCSC, UPFC & Optimal power flow (OPF) using GA & \
\begin{tabular}{c} Congestion reduced by OPF method \\ using GA to find the global \\ optimal schedule \\ \end{tabular} &
\begin{tabular}{c} Results shows that two UPFCs with a TCSC outperform one UPFC with two \\ TCSCs for reducing line loading. \\ The major drawback is the higher cost \\ \end{tabular} \\ \hline
[205] & TCSC, UPFC & Sensitivity analysis & \
\begin{tabular}{c} Congestion is removed in IEEE-30 \\ bus system using TCSCs and UPFCs \\ which significantly reduced the loss \\ and cost and resulted in \\ increased load-ability \\ \end{tabular} &
\begin{tabular}{c} The TCSC outperformed the UPFC for active power flow improvement. \\ Lack of detailed cost-effective \\ comparison of FACTS devices. \\ Future studies can be extended to power \\ quality in terms of voltage profile \\ improvements using FACTS devices \\ \end{tabular} \\ \hline
[209] & IPPC & Expected security cost using PSO & \
\begin{tabular}{c} Congestion in IEEE-30 bus system is \\ reduced by simultaneously optimally \\ placing IPFCs and minimizing \\ expected security cost using PSO. \\ Moreover, social welfare \\ maximization and generation \\ rescheduling are also considered \\ without IPFCs to reduce congestion \\ of the IEEE-30 bus system \\ \end{tabular} &
\begin{tabular}{c} The UPFC reduced congestion better than SOCBCs better than SOCBCs better than SOCBCs better than SOCBCs better than SOCBCs better than SOCBCs better than SOCBCs better than SOCBCs better than SOCBCs better power systems \\ \end{tabular} \\ \hline
[213] & \begin{tabular}{c} SVC, TCSC, \\ TCVR, TCPST, \\ UPFC \\ \end{tabular} & GA & \
\begin{tabular}{c} Graphical user interface (CUI) of \\ more than 300 IEEE bus systems is \\ considered for optimal placement of \\ FACTS devices with aim of \\ reducing congestion \\ \end{tabular} &
\begin{tabular}{c} The UPFC reduced congestion better \\ than the SVC, TCSC, TCVR, and TCPST. \\ Multiple FACTS devices perform better \\ than their individual placement in \\ power systems \\ \end{tabular} \\ \hline
[218] & SSSC, STATCOM & \begin{tabular}{c} Neural models based on \\ the averaging technique \\ \end{tabular} & \
\begin{tabular}{c} Reduced congestion in IEEE-14, 30, \\ and 118 bus systems based on \\ averaging technique and nodal \\ price indices \\ \end{tabular} &
\begin{tabular}{c} STATCOM is less effective than SSSCs for \\ alleviating congestion of \\ transmission lines. \\ Increased number of FACTS devices of \\ the same or different types can be more \\ effective than their individual \\ installation. However, FACTS device cost \\ is challenging for their selection \\ \end{tabular} \\ \hline
[189] & SVC, TCSC & \begin{tabular}{c} Mixed integer \\ optimization technique \\ \end{tabular} & \
\begin{tabular}{c} Congestion (total market cost) in \\ modified IEEE-30 bus system is \\ reduced by a combination of demand \\ response and FACTS devices \\ \end{tabular} &
\begin{tabular}{c} A combination of FACTS devices and \\ demand response is more beneficial for \\ congestion management reduction \\ \end{tabular} \\ \hline
[229] & SVC, TCSC, UPFC & GA, DE & \
\begin{tabular}{c} Optimal placement of FACTS \\ devices in IEEE-30 bus system \\ significantly reduced the active \\ power loss, transmission loss, and \\ operating cost using GA and DE \\ optimization techniques \\ \end{tabular} &
\begin{tabular}{c} Lack of optimization techniques’ \\ comparison with individual \\ FACTS devices. \\ It is concluded that the series FACTS device (TCSC) and shunt FACTS device (SVC) with a UPFC outperform their \\ combination without a UPFC \\ \end{tabular} \\ \hline
[232] & SVC, TCSC & GA, DE, PSO, GSA & \
\begin{tabular}{c} Various constraints such as active \\ power loss and operating cost of \\ IEEE-30 and 57 bus systems are \\ minimized along with enhanced \\ load-ability using FACTS devices \\ \end{tabular} &
\begin{tabular}{c} Lack of comparison about performance \\ of FACTS devices. \\ CSA performance is superior to GA, DE, and PSO. \\ The best place for SVCs is those weak \\ buses that have higher voltage deviation \\ in response to the increase in load-ability. \\ Similarly, for TCSCs the best place is \\ those transmission lines that have a \\ higher value of line stability index [215] \\ \end{tabular} \\ \hline
[238] & \begin{tabular}{c} Modular static \\ synchronous \\ series \\ compensator \\ (M-S8 SC) \\ \end{tabular} & \
\begin{tabular}{c} M-S8 SC is utilized to manage \\ congestion and increase RES \\ integration and cross-border power \\ flows in the power system by \\ adjusting transmission line reactance \\ in real time \\ \end{tabular} &
\begin{tabular}{c} Major advantages of M-S8 SC are \\ scalability, rapid deploy-ability, \\ redeployability, and lower cost \\ \end{tabular} \\ \hline \hline \end{tabular}
\end{table}