525 kV HVDC NEW CABLE SYSTEMS FOR THE ENERGY TRANSITION
PRYSMIAN GROUP | 525 kV HVDC CONNECTING THE WORLD. TODAY AND IN THE FUTURE. YEARS OF EXPERIENCE 150 R&D CENTRES AROUND THE WORLD 26 Prysmian Group is world leader in the energy and telecom cables and systems industry. With almost 150 years of experience, sales of over €16 billion, around 30.000 employees in 50 countries and 108 plants, the Group is strongly positioned in high-tech markets and offers the widest possible range of products, services, technologies and know-how.
3 We operate in the business of high voltage underground and submarine cables and systems for power transmission and distribution, special cables for applications in many different industries and medium and low voltage cables for the construction and infrastructure sectors. We manufacture cables and accessories for voice, video and data transmission for the telecom industry, offering a comprehensive range of optical fibres, optical and copper cables and connectivity systems. Sustainability is in our DNA Prysmian’s ambition is to act as an enabler to accelerate the energy transition, while also creating business value, by supporting the development of greener and smarter power grids with innovative cable technologies to cover longer distances and sea depths, ensuring higher performance, reliability and sustainability. This ambition is demonstrated by our everyday business activities to provide clean energy where it is needed, all over the world. Interconnectors between countries are another key part of the energy transition: as the backbone of power grids, cables are, and will be an essential part of this development, supporting the implementation of larger, more integrated, efficient and sustainable power transmission systems. As a company, we can play a crucial role in the global energy transition.
PRYSMIAN GROUP | 525 kV HVDC Power transmission as a function of technology 525 kV CABLE TECHNOLOGY, A STEP FURTHER 1000 525 kV extruded - 70°C Copper Cross-section [mm2] Power [MW] 525 kV extruded - 90°C 320 kV extruded - 70°C 525 kV suitable for connections above 2GW 525 kV paper - 60°C 800 1000 1600 1400 1800 2600 2800 1200 1400 1600 1800 2000 2200 2400 2600 320 kV suitable for connections up to 1.3 GW 1200 2000 MORE EFFICIENT, RELIABLE, ECO-FRIENDLY POWER TRANSMISSION Prysmian Group launched the new 525 kV HVDC cable technology, making a significant step forward towards more efficient, reliable and eco-friendly power transmission. 525 kV extruded land cable systems are qualified with two different insulation materials, P-Laser and XLPE. They are both designed to operate at very high electrical stresses and are tested with large conductor cross-sections to maximize power transmission over long distances with minimized land use. For example, the ±525 kV technology uses less cable to transmit the same power compared to classic 380 kV AC systems. This is reflected in less construction efforts when installing the cables and narrower trench widths. P-Laser also benefits from a higher operating temperature than classic HVDC systems at 320 kV, further increasing its power transmission capacity. Calculated in ambient conditions with soil thermal resistivity of 0.8 mK/W, ambient temperature of 18°C, burial depth of 1.5m and cables installed in bundle
5 525kV systems are effective solutions able to connect power generation areas such as wind generation-rich regions to major consumption centers, typically located far from renewable energy sources, reducing the required land usage and ensuring lower environmental impact. 525 kV XLPE submarine cable systems are also successfully developed and tested according to International Standards. This breakthrough innovation will enable a massive increase in the transmission capacity of Bipole systems of up to 2.5 GW, which is almost twice the value achieved with 320 kV DC systems currently in service. This is key to connecting huge amounts of green energy to the grid such as next generation offshore windfarms. The pace at which renewable power needs to be connected each year has to increase to meet challenging targets set worldwide to lower carbon emissions: increasing the power each link can transmit is the only way to deploy the needed energy infrastructure in time. The company leveraged on extensive and in-depth knowledge of materials and manufacturing processes, successfully optimizing the industrial process while keeping reliability and guaranteeing strict technological parameters. An entire system of submarine cable and accessories - including flexible factory joints, rigid repair joints and sea-land joints - with the best dielectric properties was successfully developed and is now available on the market. Prysmian Group wanted to take things a step further confirming its role and commitment in the development of power grid infrastructure, empowering its customers in the continuous effort towards the energy transition to reach the EU 2050 goal of having 300 GW of offshore wind power and also reducing infrastructure costs for the benefit of energy bills and final consumers. TRANSMISSION CAPACITY up to 2.5 GW A CONTINUOUS EFFORT TOWARDS THE ENERGY TRANSITION
PRYSMIAN GROUP | 525 kV HVDC XLPE technology XLPE insulation technology is based on polyethylene and requires a cross-linking process, which is essential for stabilizing the insulation material. This process determines the presence in the insulation of crosslinking by-products (such as methane, cumyl alcohol, acetophenone, etc.). These by-products should be removed, after the crosslinking with a specific thermal treatment process, known as “degassing”. The degassing operation decreases the amount of residual by-products present in the cable. Electrical and thermomechanical working performance should be selected accordingly, to guarantee reliable system operations at the ever-increasing voltage levels. MAIN XLPE TECHNOLOGY ADVANTAGES: PERFORMANCES: High transmission power, longer transmission lengths with lower system losses Insulation and accessories tested up to 600 kV DC Underground and submarine cable systems fully qualified up to 525 kV in accordance with CIGRE Technical Brochure 852 Using the technological platform used for XLPE AC and DC cables Further optimization of 320 kV voltage class Higher operating temperatures than classic paper cables Higher electrical strength than state-of-the-art 320 kV extruded systems Very low electrical conductivity and high thermal stability The newly developed XLPE material presents higher cleanliness and lower electrical conductivity, allowing for an increase of the maximum allowable electrical stresses in the insulation (if compared to the previous XLPE materials), meaning that the conductivity is more stable between cold and hot conditions. As a result, it is possible to reach cable voltage levels up to 600 kV, while reducing thicknesses at standard voltages with lighter and less expensive cables.
7 XLPE DATASHEET | Land CONDUCTOR Bare copper wires filled with water swellable tapes, with nominal cross-section area up to 4000 mm². Aluminum is also available. INSULATION Low peroxide XLPE. METALLIC SHEATH The smooth metallic sheath is constituted by a longitudinally welded aluminum tape (WAS) applied over the outer semiconductive layer and water barrier, to provide water tightness, mechanical protection and to carry fault currents. OUTER SEMI-CONDUCTIVE LAYER Water-swellable tapes and extruded semi-conducting screen layer, to have a smooth electrical interface with insulation. OUTER SHEATH An extruded layer of red or black colored high density polyethylene compound is provided over the metallic sheath. An extruded black semi conductive layer can be applied over the outer sheath for after installation tests. Flame retardant and low smoke versions are available. Dimensional data for 3000 mm2 copper Electrical data for 3000 mm2 copper Indicative diameter 140 mm Indicative cable weight 40 kg/m Ohmic resistance 0.0060 Ω/km Coaxial inductance 0.14 mH/km Capacitance 0.24 µF/km INTEGRATED FO CABLE Up to 4 integrated fiber optic elements for monitoring purposes, able to accommodate both multi-mode and single-mode fibers. INNER SEMI-CONDUCTIVE LAYER Water-swellable tapes and extruded semiconducting screen layer, to have a smooth electrical interface with insulation.
PRYSMIAN GROUP | 525 kV HVDC XLPE DATASHEET | Submarine CONDUCTOR Bare copper wires filled with sea-grade water blocking compound, with nominal cross-section area up to 3500 mm². Aluminum is also available. INSULATION Low peroxide XLPE. METALLIC SHEATH The insulated core has a lead alloy sheath applied over the longitudinal water barrier. ARMOUR Single or double layer of galvanized steel round wires, flushed with bitumen as further anti-corrosion protection. Double steel layer or Composite armour designs for high depth applications are also available. SERVING Two layers of polypropylene strings, to protect against abrasion and reduce cable friction. INNER SEMI-CONDUCTIVE LAYER Water-swellable tapes and extruded semi-conducting screen layer, to have a smooth electrical interface with insulation. OUTER SEMI-CONDUCTIVE LAYER Water-swellable tapes and extruded semiconducting screen layer, to have a smooth electrical interface with insulation. ANTI-CORROSION SHEATH An extruded layer of insulating polyethylene compound; to avoid any electrical breakdown by induced over-voltages, the metallic sheath is short-circuited with the armour wires at intermediate distances. Semiconductive polyethylene is also available. INTEGRATED FO CABLE Up to 4 integrated fiber optic elements for monitoring purposes, able to accommodate both multi-mode and single-mode fibers. Dimensional data for 2500 mm2 copper Electrical data for 2500 mm2 copper Indicative diameter 160 mm Indicative cable weight 65 kg/m Ohmic resistance 0.0072 Ω/km Coaxial inductance 0.15 mH/km Capacitance 0.22 µF/km
9 P-Laser technology P-Laser cable technology is based on a High-Performance Thermoplastic Elastomer (HPTE) insulation, an in-house developed insulation material based on polypropylene. The excellent electrical properties of polypropylene are well known; however, intensive R&D work was needed to achieve a combination of excellent values of flexibility and thermomechanical properties. Compared to XLPE, HPTE does not require any crosslinking process and therefore does not require the time and energy consuming degassing process. Being intrinsically free of any cross-linking by products, P-Laser insulation performances are outstanding, and it can safely withstand demanding electrical stresses such as polarity reversals and transient overvoltages. MAIN P-LASER TECHNOLOGY ADVANTAGES: PERFORMANCES: High transmittable power, help avoiding hotspot issues along the route, easier to switch to aluminum conductors Lower environmental impact and carbon footprint Insulation and accessories tested up to 600 kV DC Underground cable systems fully qualified up to 525 kV in accordance with CIGRE Technical Brochure 852 Full compatibility with existing HVDC cable accessories P-laser cables in construction phase for >1000 km 320 kV and 525 kV HVDC projects High operating temperature up to 90°C High electrical strength, capable to better withstand polarity reversals and transient overvoltages Reduction of CO2 emissions by up to 30% and 100% eco-friendly and fully recyclable materials* *Refers to the end-of-life phase of Life Cycle Assessment (LCA) evaluation HPTE is designed for operation at 90°C. This allows, in comparison to operation at 70°C, to either transmit more power or to reduce the cable cross section and thus investment costs. Also, this feature can be used to operate the link at increased safety margins. PLaser is fully recyclable, a key advantage for the end of life stage of obsolete HVDC links. As the production process with PLaser has a low energy consumption, it has an overall reduced carbon footprint compared to XLPE up to 30%. P-Laser technology is fully compatible with existing cable accessories and can be integrated in networks using different insulation technologies.
PRYSMIAN GROUP | 525 kV HVDC P-LASER DATASHEET | Land CONDUCTOR Bare aluminum wires filled with water swellable tapes, with nominal cross-section area up to 4000 mm². Copper is also available. METALLIC SHEATH The smooth metallic sheath is constituted by a longitudinally welded aluminum tape (WAS) applied over the outer semiconductive layer and water barrier, to provide water tightness, mechanical protection and to carry fault currents. INNER SEMI-CONDUCTIVE LAYER Water-swellable tapes and extruded semiconducting screen layer, to have a smooth electrical interface with insulation. OUTER SEMI-CONDUCTIVE LAYER Water-swellable tapes and extruded semiconducting screen layer, to have a smooth electrical interface with insulation. OUTER SHEATH An extruded layer of red or black colored high density polyethylene compound is provided over the metallic sheath. An extruded black semi conductive layer can be applied over the outer sheath for after installation tests. Flame retardant and low smoke versions are available. Dimensional data for 3500 mm2 aluminum Electrical data for 3500 mm2 aluminum Indicative diameter 155 mm Indicative cable weight 25 kg/m Ohmic resistance 0.0081 Ω/km Coaxial inductance 0.13 mH/km Capacitance 0.25 µF/km INSULATION P-Laser, based on HPTE insulation material which is fully recyclable and compatible with existing cable accessories. INTEGRATED FO CABLE Up to 4 integrated fiber optic elements for monitoring purposes, able to accommodate both multi-mode and single-mode fibers.
11 P-LASER DATASHEET | Submarine INNER SEMI-CONDUCTIVE LAYER Water-swellable tapes and extruded semiconducting screen layer, to have a smooth electrical interface with insulation. OUTER SEMI-CONDUCTIVE LAYER Water-swellable tapes and extruded semi-conducting screen layer, to have a smooth electrical interface with insulation. ANTI-CORROSION SHEATH An extruded layer of insulating polyethylene compound; to avoid any electrical breakdown by induced over-voltages, the metallic sheath is short-circuited with the armour wires at intermediate distances. Semiconductive polyethylene is also available. INTEGRATED FO CABLE Up to 4 integrated fiber optic elements for monitoring purposes, able to accommodate both multi-mode and single-mode fibers. Note: Technology under development CONDUCTOR Bare aluminium wires filled with sea-grade water blocking compound, with nominal cross-section area up to 3500 mm². Copper is also available. INSULATION P-Laser, based on HPTE insulation material which is fully recyclable and compatible with existing cable accessories. METALLIC SHEATH The insulated core has a lead alloy sheath applied over the longitudinal water barrier. ARMOUR Single or double layer of galvanized steel round wires, flushed with bitumen as further anti-corrosion protection. Double steel layer or Composite armour designs for high depth applications are also available. SERVING Two layers of polypropylene strings, to protect against abrasion and reduce cable friction. Dimensional data for 2500 mm2 aluminum Indicative diameter 160 mm Indicative cable weight 50 kg/m Electrical data for 2500 mm2 aluminum Ohmic resistance 0.0119 Ω/km Coaxial inductance 0.15 mH/km Capacitance 0.22 µF/km
PRYSMIAN GROUP | 525 kV HVDC Mass Impregnated Non Drained Technology Mass Impregnated Non Drained (MIND) cables are suitable for voltages of up to 600 kV DC. The insulation consists of high-density paper tapes impregnated with a high-viscosity compound which does not require fluid pressure feeding, thus allowing cables to be installed in HVDC links in very long lengths, up to several hundreds of kilometers. Nevertheless, they have intrinsic limitations in power given by kraft paper’s electrical and thermal performances. Research and development work on materials and technologies carried out by Prysmian over the years has led to a product that can operate up to 60°C and has the longest track record of operation at 525 kV voltage level. MIND cables are still of interest for all applications where thermal performances are limited by other factors or aren’t the main design driver, such as limitation of transmission losses, environmental constraints, or high depth applications. MAIN MIND TECHNOLOGY ADVANTAGES: PERFORMANCES: Largest track record and high reliability for 525 kV voltage level Field proven designs for high depth applications Competing solution for low transmission loss applications Operating temperature up to 60°C High electrical strength, capable to withstand polarity reversals and transient overvoltages Laboratory and Field proven capability for high water depths Prysmian’s special armour design enables record installation depths exceeding 2200 m, using special armour design features also developed by Prysmian. MIND cables are the only technology installed and in operation at 1600 m. For high depth applications, mechanical constraints reduce the crosssection disadvantage with extruded cables. The thin insulation package typically used in MIND cables is beneficial in reducing the cable weight and pulling tensions during installation. This doesn’t affect the current rating, as thermal conditions at high depths are more favorable thanks to lower temperatures and large distances between pole cables, not installed in bundle.
13 MIND DATASHEET | Submarine Dimensional data for 1200 mm2 aluminum Electrical data for 1200 mm2 aluminum Indicative diameter 135 mm Indicative cable weight 30 kg/m Ohmic resistance 0.0247 Ω/km Coaxial inductance 0.16 mH/km Capacitance 0.33 µF/km INNER SEMI-CONDUCTIVE LAYER Carbon black paper layers OUTER SEMI-CONDUCTIVE LAYER Carbon black and metallized paper layers. ANTI-CORROSION SHEATH An extruded layer of semiconductive polyethylene compound, to avoid any electrical breakdown by induced over-voltages. Insulating polyethylene is also available for metallic armours. SERVING Two layers of polypropylene strings, to protect against abrasion and reduce cable friction. CONDUCTOR Aluminum keystone conductors, with nominal cross-section area up to 2500 mm². Copper is also available. INSULATION High density wood pulp paper tapes, impregnated with fully degasified special viscous compound. METALLIC SHEATH The insulated core has a lead alloy sheath applied over the longitudinal water barrier. REINFORCEMENT One layer of steel tapes, to allow for proper thermal expansion and contraction of the MIND insulation. ARMOUR Double layer of composite wires, specially designed for high depth applications, combining light weight features with high tensile strength performances. Steel wires or single layers designs are also available.
PRYSMIAN GROUP | 525 kV HVDC Milestone projects HVDC UNDERGROUND INTERCONNECTIONS 1. SuedOstLink Insulation: P-LASER Power transmitted: 2,000 MW (the first project to use extruded cables at this highest voltage level) 270 KM Prysmian cable route 550 KM of Prysmian HVDC underground cables Insulation: XLPE 2. SuedLink Power transmitted: 2,000 MW 580 KM Prysmian cable route 1,200 KM of Prysmian HVDC underground cables Insulation: P-LASER 3. A-Nord Power transmitted: 2,000 MW 300 KM Prysmian cable route 640 KM of Prysmian HVDC underground cables 3. 2. 1. 4. 5. 6.
15 HVDC SUBMARINE INTERCONNECTIONS 4. North Sea Link CONNECTING UK AND NORWAY Power transmitted: 1,400 MW 950 KM of Prysmian submarine cables 1,500 KM of Prysmian land cables Insulation: MIND 5. Viking Link CONNECTING UK AND DENMARK Power transmitted: 1,400 MW 1,250 KM of Prysmian submarine cable 135 KM of Prysmian land cables Insulation: MIND 6. Tyrrhenian Link CONNECTING SARDINIA, SICILY AND CAMPANIA Power transmitted: 1,000 MW 1,500 KM of Prysmian submarine cables 2,200 M max water depth Insulation: MIND
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