# Optimal Placement of Multiple Feeder Terminal Units Using Intelligent Algorithms
## 5 Case Study and Discussion
### Comparative Analysis of Configuration Schemes
This result can only reflect that with the parameters obtained from the actual research of a certain area in China in this paper, it is better to only consider \"three remote\" terminal units' locations than to configure three types of FTUs concurrently from the perspective of LCC. In the case of other values of the input parameters, it cannot be denied that the distribution network with multiple FTUs configurations may perform better. It should be noted that the data in row 2 of Table 7 is different from that in row 4 of Table 5 (both are solved by DPSO), because the result in Table 7 is the optimal value of 10 simulation runs, while the result in Table 5 is the average value obtained from the 10 simulation runs. The results of Table 7 are analyzed as follows:  
(1) By comparing the calculation results of scheme 1, 2, and 3, it can be seen that:  
Compared to scheme 3, the reliability indices SAIDI of the configuration scheme given in the proposed model (scheme 1) is increased by 1.458 min/yr.cust, with SAIFI almost unchanged, CAIDI increased by 9.948 min/yr.cust, and ASAI decreased by 0.0003%; however, its initial investment cost is reduced by 46.155% (25.45 k$), and its LCC is decreased by 2.378% (14.2151 k$). This results show that although scheme 3 realizes the most reliable operation, the blind and comprehensive configuration of \"three remote\" terminal units is not necessarily the optimal scheme when economy and reliability are considered simultaneously with the only variable, i.e., FTUs' placement. It can be seen that the evaluation indexes of scheme 2 is close to that of scheme 1. Therefore, the comparison results of scheme 2 and scheme 3 are similar to those of scheme 1 and scheme 3. In scheme 2, multiple FTUs are configured for the distribution network. The evaluation index of scheme 2 in Table 7 strongly shows that from the perspective of LCC, the distribution network considering multiple FTUs optimal configuration is better than configuring \"three remote\" terminal units blindly and widely. This verifies the significance of optimizing the configuration of feeder automation terminals in distribution network. This conclusion is more meaningful in suburbs or rural areas without large-scale industry and commerce. The reliability requirements of distribution network in these areas are not as high as those in cities or downtown areas. The FTUs configuration scheme obtained by the proposed optimization model can not only meet the reliability constraints of the area, but also perform better in economy. (2) By comparing the calculation results of four schemes in Table 7, it can be seen that:  
The sum of outage loss and maintenance cost accounts for a large proportion, and the cost is generated every year in the whole life cycle of distribution network, which proves the superiority of terminal configuration optimization model based on the whole LCC. Therefore, it should be fully considered in the planning stage of distribution network project. (3) By comparing the calculation results of scheme 1 and scheme 4, 5, it can be seen that:  
The LCC of the planning scheme with the minimum initial investment cost (scheme 4) or the minimum sum of initial investment cost, maintenance cost and outage loss (scheme 5) as the objective function is greater than that of scheme 1, so they are not the scheme with the minimum LCC. The initial investment cost of scheme 1 is 281% (21.91 k$) and 121% (16.26 k$) higher than that of scheme 4 and scheme 5, respectively, while the annual outage loss of distribution network is reduced by 14.199% (17.87 k$) and 8.771% (10.38 k$) respectively. Such loss reduction is considerable after accumulating every year. Therefore, the initial investment cost in the early stage has a certain impact on the cost generated in the operation stage of the distribution network project. The high initial investment of FTUs may reduce the future outage loss, thus reducing the LCC of the configuration scheme.