Concept Design and Development of a Module for the Construction of Reversible HVDC Submarine Deep-Water Sea Electrodes

Molfino, P.; Nervi, M.; Rossi, Mansueto; Malgarotti, S.; Odasso, A.

doi:10.1109/tpwrd.2016.2555882

Cited by 9 publications

(6 citation statements)

References 5 publications

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“…If it is not possible to cover wide areas, the current density will be higher, leading to high values of the electric field, which cannot be tolerated, for example, by fishes and scuba divers. For this reason, in these cases, the electrodes are usually made of a graphite bar, platinized titanium or mixed-metal-coated titanium inserted inside a box [15], eventually filled with coke. The function of coke is to reduce the corrosion rate of the active parts, since the conduction mechanism between the active parts and coke is mostly electronic instead of ionic, and thus, corrosion is greatly reduced.…”

Section: Sea Electrodesmentioning

confidence: 99%

An Overview on Reversible Sea Return Electrodes for HVDC Links

et al. 2023

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HVDC electrodes are usually implemented in HVDC links to avoid the installation of a metallic return. Submarine cables, especially those dealing with lengths of thousands of kilometers, are expensive, and high costs of laying are normally expected. Due to the high number of reversible HVDC links, the marine electrodes must be able to withstand both anodic and cathodic operations, which leads to careful considerations in terms of the material to be used. This paper shows the state of the art of the currently installed reversible sea return electrodes, focusing on the type of installation (sea, shore or pond electrodes) and on the material used, from the first plant installed in 1954 up to the more recent ones established during the XXI century. All reported data derive from publicly available sources. Moreover, since nowadays environmental issues are among the most important topics, for each material and for each type of installation, a guideline on the possible interferences caused by marine electrodes with the surrounding environment is proposed.

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Section: Sea Electrodesmentioning

confidence: 99%

An Overview on Reversible Sea Return Electrodes for HVDC Links

et al. 2023

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“…As early as 1951, a U.S. naval shipyard built a deep sea pressure simulation device, achieving a cyclic pressurization of 0.1-4 MPa with a maximum pressure of 4.2 MPa [7]. After that, a device with a maximum pressure of 82.75 MPa was developed [8].…”

Section: Related Workmentioning

confidence: 99%

An Innovative System of Deep In Situ Environment Reconstruction and Core Transfer

Peng

Yang

et al. 2023

Applied Sciences

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The reconstruction of deep in situ environment up to 95 °C and 70 MPa using water is critical for the fidelity testing of deep Earth rocks. The temperature and pressure of the water have strong coupling in such an environment, which makes the control of temperature and pressure very difficult. The paper firstly presents the design of the system of deep in situ environment reconstruction and core transfer (SERCT); secondly, for the problem of high temperature and pressure control, a pressure-temperature (P-T) interpolation control algorithm based on the iso–density P-T curves of water is proposed. A P-T coupling control path is decomposed into two independent interpolation paths: an iso–thermal pressure control and an iso–mass temperature control, which realizes the decoupling control of temperature and pressure. Then, a fuzzy-PID dual mode method is adopted for the pressure control after decoupling, which reduces the overshoot and the dynamic response time of the system. For temperature control, a segmented and grouped electric heating mode is designed to improve the uniformity of the temperature field. A fuzzy PID temperature control algorithm based on grey prediction is proposed to achieve high precision temperature control with small overshoot. Finally, the effectiveness of the proposed methods is verified by experiments.

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“…Step and touch voltages should also be eliminated according to IEC 60749-1:2007 [17] (pp. [59][60][61][62][63][64][65][66][67][68][69][70]. From the six usual types of electrodes (land-shallow horizontal, land vertical, land-deep well, sea, shore-beach, shore-pond) according to [17] (p. 19), the shoreline pond electrode was selected for which the determination of the electric field and the potential rise was calculated according to the guidelines of CIGRE B4.61 675:2017 [17].…”

Section: Introductionmentioning

confidence: 99%

“…The detailed solution of the field of a shoreline pond anode electrode is mentioned in technical reports about Italy-Greece Interconnection, such as [60]. EPRI proposes the use of numerical algorithms using resistivity data from geophysical methods [45], which are more widely used in grounding electrodes [61] but also in sea electrodes [58,62,63]. In [62], both near and far electric fields were analyzed, using the numerical methods of hemispheroidal, finite volume element and inclined layer, and finally proposes the use of the first two methods [64,65] that have finite limits on the volume of water for the calculation of the scalar potential and ground potential.…”

mentioning

confidence: 99%

“…In [62], both near and far electric fields were analyzed, using the numerical methods of hemispheroidal, finite volume element and inclined layer, and finally proposes the use of the first two methods [64,65] that have finite limits on the volume of water for the calculation of the scalar potential and ground potential. In [63,66], the use of the finite element method for near-field analysis was suggested. Alternatively, semi-analytical methods can be used, such as the complex images method with a "generalized pencil of functions" interpolator, achieving numerical convergence and solution stability with satisfactory results in the HVDC electrode study [67], which was confirmed with the help of finite elements in grounding systems [68].…”

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confidence: 99%

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Alternative Simplified Analytical Models for the Electric Field, in Shoreline Pond Electrode Preliminary Design, in the Case of HVDC Transmission Systems

et al. 2022

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In Greece, a new bi-polar high voltage direct current (HVDC) transmission system with a ground return was designed with nominal characteristics of ±500 kV, 1 GW, between Attica in the continental country and the island of Crete, which is an autonomous power system based on thermal diesel units. The interconnection line has a total length of about 380 km. The undersea section is 330 km long. In this paper, the use of the Aegean Sea as an active part of the ground return, based on shoreline pond electrodes, was proposed to avoid EUR 200 Μ of expenses. According to the general guidelines for HVDC electrode design by the International Council on Large Electric Systems (CIGRE) working group B4.61/2017, the electric field and ground potential rise of shoreline electrodes should be studied to analyze safety, electrical interference and corrosion impacts related to the operation of the electrodes. Two kinds of studies are available; one is a simplified approach based on a spherical/pointed electrode centered at the edge of the seashore and seabed, assuming it to be sloping to the horizontal, and the other is a detailed simulated model using a suitable electric field software package. The first approach usually gives more unfavorable results than the second one, especially in the near electric field, while it can not take into account obstacles, i.e., dams, near to electrode position. The second approach demands a detailed description of the wider installation area, which cannot be available during the preliminary study, significant computational time and considerable financial resources for the purchase of a reliable specialized software package. In this research, a two-step modification of the CIGRE simplified model was proposed. The first modification deals with the obstacles in the near electric field, and the second modification deals with the use of a linear current source (instead of a point one), which can give more accurate results. Additionally, the electric field for complex electrode formation is calculated by applying the superposition method, which can be easily achieved using a common software package, i.e., MATLAB. The proposed simplified approaches were applied on shoreline pond electrode locations for the Attica–Crete HVDC interconnection line (between Stachtoroi island in Attica and Korakia beach in Crete), allowing the preliminary study to be conducted swiftly, giving satisfactory results about electric field gradient, ground potential rise and resistance to remote earth of electrodes stations for the near and far electric field.

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Concept Design and Development of a Module for the Construction of Reversible HVDC Submarine Deep-Water Sea Electrodes

Cited by 9 publications

References 5 publications

An Overview on Reversible Sea Return Electrodes for HVDC Links

An Overview on Reversible Sea Return Electrodes for HVDC Links

An Innovative System of Deep In Situ Environment Reconstruction and Core Transfer

Alternative Simplified Analytical Models for the Electric Field, in Shoreline Pond Electrode Preliminary Design, in the Case of HVDC Transmission Systems

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