# Multi-Stage Dynamic Transmission Network Expansion Planning Using LSHADE-SPACMA
## 6 Conclusions and Future Works  
The implementation of the LSHADE-SPACMA algorithm was investigated to solve the TNEP problem. Promising results were obtained using three sample systems and confirmed the potential of this approach. The results show that the LSHADE-SPACMA algorithm produces a better (low-cost) solution than IBPSO, MVO, and HT for the WDN. Moreover, the LSHADE-SPACMA reached optimum solutions for both large- and small-scale systems such as the Colombian system and the Garver test system in a single run. Ignoring N-1 reliability constraint in the TNEP model threatens the security of power systems. A suggested approach to tackle this problem was applied to the Egyptian WDN, and its performance was evaluated. The MSDTNEP up to year 2040 including an N-1 security constraint, and it was assessed based on two scenarios. Scenario 1 adopted plans based on the candidate routes with the implementation of load shedding. Scenario 2, the suggested solution, assumed that the maximum number of circuits in each line could be increased to 4. ANFIS was employed to predict load demand growth until 2040. The input and the output of ANFIS are the historical year and the actual peak load data, respectively. The numerical results show that dynamic planning leads to a more accurate and realistic assessment of the network. Moreover, the N-1 security constraint has a significant impact on the final configuration of WDN. The results also demonstrate that the planning of WDN with the candidate lines proposed in scenario 1 cannot guarantee system security without imposing a load shedding or partial blackouts. It should be noted that scenario 1 results in the addition of 31 circuits with load shedding of 627.96 MW at the end of the planning horizon. The total investment cost is estimated to be 287.46 million USD. Scenario 2 does not cause blackouts and is recommended. This scenario requires the addition of 62 circuits with no load shedding and an investment cost of 57.33 million USD. The results demonstrated that the suggested strategy is considered a promising solution to maintain N-1 security and avoid rolling blackouts. It is applicable for all power systems because it is not complex and has a low investment cost [34]. Egypt's vision is to achieve an energy sector that meets national sustainable development standards and optimizes the use of renewable resources to support economic growth and protect the environment's health and quality [35; 36]. Hence, a new paradigm of transmission and generation planning for WDN is needed, which considers the system's increasingly decentralized and stochastic nature due to the predicted high penetration of renewable energy sources in the Egyptian network. Figure 7: Comparison between scenarios 1 and 2. **Author Contributions:** [PERSON] and [PERSON] designed the problem under study; [PERSON] performed the simulations and obtained the results; [PERSON] analyzed the obtained results; [PERSON] wrote the paper, which was further reviewed by S.H.E.A.A., Y.A., M.M.S., and Z.M.A. All authors have read and agreed to the published version of the manuscript. **Funding:** This research received no external funding. **Institutional Review Board Statement:** Not applicable. **Informed Consent Statement:** Not applicable. **Data Availability Statement:** The data presented in this study are available on request from the corresponding author. The data are not publicly available due to their large size. **Conflicts of Interest:** The authors declare no conflict of interest.