## 3 Electrode Station Configuration
### General Remarks
Basic Electrode Station Configuration--Straight Frames in Series, Each Placed Parallel to the Longitudinal Axis of the Dam (1 st Configuration)  
From the respective study of the electric field, according to Section 5.4 in [2], for the Korakia area, the values of the corresponding geometric quantities for vertical electrodes are \(t_{d}\) = 5.0 m at sea level and 18.0 m at a depth of 2.60 m; \(d_{r1}\) = 1.0 m; \(\ell_{f}\) = 6.0 m; \(d_{fp}\) = 10.90 m; \(s_{c}\) = 8.53 m, which, for reasons of location, was reduced to 6.5 m; \(d_{stv}\) = 50.3 m; \(\ell_{chf}\) = \(\ell_{cud}\) = 67.80 m; \(\ell_{p}\) = 0.50 m; \(h_{u}\) = 1.50 m; \(h_{m}\) = 2.57 m; \(h_{d}\) = 3.63 m; and \(h_{sb}\) = 5.00 m. The difference between the estimated width of the frame critical zone \(d_{fp}\) and the actual required width \(d_{stv}\) of the electrode station critical zone is very large (5 times larger), as is the difference between the distance \(s_{c}\) and the actual required length (as determined by the calculation \((\ell_{cud}-3\cdot\ell_{f})/3.5=14.23\) m), which is almost double. The electrode-station-to-remote-earth resistance \(R_{el}\) and the maximum value of the absolute potential \(V_{rd\_max}\), amount to 19.51 \(\Omega\) and 22.77 kV, respectively. The worst results occur during maintenance of the first or sixth frame. From the respective study of the electric field, for the area of Stachtoroi, according to Section 5.4 in [2], the values of the corresponding geometric quantities for vertical electrodes are: \(t_{d}\) = 5.0 m at sea level and 16.0 m at a depth of 3.0 m; \(d_{r1}\) = 1.0 m; \(\ell_{f}\) = 6.0 m; \(d_{fp}\) = 7.95 m; \(s_{c}\) = 5.80 m, which, for reasons of location, was reduced to 4.50 m; \(d_{stv}\) = 36.3 m; \(\ell_{cbd}\) = \(\ell_{cud}\) = 52.30 m; \(\ell_{p}\) = 0.50 m; \(h_{u}\) = 1.00 m; \(h_{m}\) = 2.07 m; \(h_{d}\) = 3.13 m; and \(h_{sb}\) = 3.50 m. The difference between the estimated width of the frame critical zone \(d_{fp}\) and the actual required width \(d_{stv}\) of the electrode station critical zone is again large (4.5 times larger), as is the difference between the distance \(s_{c}\) and the actual required length (as determined by the calculation \((\ell_{cud}-3\cdot\ell_{f})/3.5=9.8\) m), which is 1.5 times larger than required. The electrode-station-to-remote-earth resistance \(R_{el}\) and the maximum value of the absolute potential \(V_{rd\_max}\), amount to 14.82 \(\Omega\) and 17.30 kV, respectively. The worst results occur during maintenance of the first or sixth frame. Essentially, it turns out that the estimation of the electric field strength through a single frame is not sufficient and the placement of the electrodes inside the respective pond, parallel to the axis of the dam, is marginally performed, achieving (in the area of the frame that does not operate for maintenance reasons/fault) electric field strengths of the order of 3 V/m, which are higher than the 2.5 V/m required by [1], for the unprotected diver next to the electrode. The corresponding easement area in front of the dam extends to 45 m in order to ensure an electric field strength of less than 1.25 V/m, which is set as a limit of non-disturbance of all kinds of marine mammals, according to [1; 27; 35]. However, this arrangement is the most typical of near-shore submerged electrodes and is distinguished for the easy suspension-lifting-positioning system of electrodes due to their proximity to the dam. Second Electrode Station Configuration--Straight Frames in Series, Each Vertically Placed on the Longitudinal Axis of the Dam  
The respective configuration of the electrode station is conducted according to Figure 6, where the straight frame has the characteristics of the basic configuration (\(N_{d,frame}\) = 13, \(\ell_{p}\) = 0.50 m, \(\ell_{f}\) = 6.00 m).