## 3 Electrode Station Configuration
### General Data
In the transient state, for a current \(I_{tot\_tr}\) of 12.8 kA, the final current density values \(J_{fit\_lo\_tr}\) (under full-load conditions) and \(J_{int\_tr}\) (under periodic maintenance) result as equal to 213.28 A/m\({}^{2}\) and 255.93 A/m\({}^{2}\), respectively. * The soil electrical resistivity takes the infinitive value, for the sake of simplifying the calculation process, giving more unfavourable/safe results. * The water zone that corresponds to an arc of angle \(\theta_{g}\), on the floor plan in Figure 1, is disregarded to simplify the calculation, giving more unfavourable/safe results. * The breakwater/dam of Figure 1 is disregarded in order to simplify the respective calculation. This affects the electric field strength calculation along with that of the absolute potential, concerning radii within or up to the breakwater. The absolute potential on the dam can be calculated approximately as the product of the respective electric field strength of the seawater and the ratio of the electrical resistivities \(\rho_{d}\)/\(\rho_{w}\). The last three assumptions were also made during the study of the basic form of the electrode stations in Section 5.1 in [2]. Furthermore, from the respective study, using a single source (Tables 2-7, Section 4 in [2]), it was found that in the present case, the worst scenario in terms of electric field strength limits is the application of the steady-state current, and this is the reason why only this is examined next. In addition, from the respective study of a straight frame of 13 electrodes at equal distances, ranging from 0.2 m to 1.5 m (Tables 9-11, Section 5 in [2]), it was found that increasing the distance between the electrodes reduces slightly the maximum electric field strength and the necessary safety distance, in terms of electric field strength limits, in front of the dam in the open sea. On the other hand, the necessary length of the dam increases significantly, while the estimated area of the critical zone (i.e., the zone formed by the six frames, within which the electric field strength may be beyond the require limits, depending on the loading) varies significantly. Balancing between the opposing results, and for reasons of electrode repairaibility by a diver/worker, a distance \(\ell_{p}\) between electrodes equal to 0.5 m is chosen. Basic Electrode Station Configuration--Straight Frames in Series, Each Placed Parallel to the Longitudinal Axis of the Dam (1 st Configuration)  
The usual configuration is the placement of straight frames in series, parallel to the longitudinal axis of the protective dam, at equal distances between them, as already presented in Figure 4 and analysed in Section 5 in [2]. This positioning is very simple in form, but presents a number of problems, especially regarding the violation of the electric field strength limits, both between the frames during the maintenance phase and in front of the dam in the open sea area, in the cases where the dam length is limited. In addition, it was found in paragraph 5.4 in [2] that the most unfavourable results are observed during the steady state in the maintenance phase of a frame, which is when one of the six frames is out of service.