Evolution of HV Cable Systems Marco Marelli Chair Cigré SC B1 “Insulated Cables”

POWER SYSTEMS OF THE FUTURE Cable Systems are evolving in their technologies and applications «Traditional» HV, EHV Power Transmission RES (Renewable Energy Sources) applications, in particular Wind Energy Cigré SC B1 monitor and cover all aspects

HV, EHV Power Transmission In HV AC the drivers are mostly cost-related e.g. use of Al conductors Interest in increasing the voltage level (UHV), and use of new cable technologies, including newer materials Number of long interconnectors at all stages (from planning to construction, both full-land and submarine) is increasing, and they are larger than ever. They are typically made or planned to be in DC. HVAC cables are currently limited to lengths of approx. 100 km. Longer lengths are possible at low frequencies or with intermediate compensation Evolution of HVDC cable technology and of converters technology are related. There is room for closer relations between B1 and B4, and some work of D1 in new (joint?) testing technologies. Overvoltages and surges phenomena associated to new converter topologies and multi-terminal schemes, may not be covered by current cable recommendations. New researches mainly related to GIL (e.g. use different gasses) and/or superconductors (also in DC)

Wind Energy Most of developments are on offshore wind energy. Need for cheap solution e.g. wet design submarine cables at 72.5 kV level. Need for fast-track standardization works positively faced by Cigrè SC B1. MVDC (from ±30 to ±100 kV DC) cables between wind turbines may happen in 5-10 years. Evaluation of different transmission modes e.g. using 16.7 Hz 245 kV three core cables to connect far distant wind farms up to 300 km from shore. New offshore network concepts, including cheaper solution for platforms and turbines, may have impact on cable installations with reduced space available (need for more compact cable layout) and removal of J-tubes (need of dynamic cables for array connections)

Other Renewable Energy Sources Solar Energy Continuous heavy cycling load can stress cables and accessories if not properly sized, adequate recommendations for proper design-installation- test seem to exist within Cigré. No new testing recommendations from other organizations are known at this time. The majority of large scale solar power generating plants is constructed by non-traditional transmission line owners. Communication regarding Cigré experience and expertise to non-traditional developers should help facility successful projects. Wave and Tidal Energy Quite small area for the moment. Cables are in the LV-MV range, with added mechanical features; TB 623 “Recommendations for Mechanical Testing of Submarine cables” should cover most of mechanical issues Wet connectors not covered by standards, they could be potential weak object in the system

TECHNICAL DIRECTIONS of Cigré and of SC B1 “Power Systems of the Future” and “Best Use of Existing Systems” remain the main focus of most of the work More attention to environmental issues Improved communication with stakeholders, starting from listening their needs

NEW WORKING BODIES of SC B1 The following WGs have been decided during SC Meeting and their ToRs prepared and approved by the TC Chairman during the second half of 2016: WG B1.58 Asset Management in MV Cable Systems (Detlef Wald/CH) WG B1.60 Maintenance of HV Cable Systems (Bart Mampaey/BE) WG B1.61 Installation of HV Cable Systems (Eugene Bergin/IR) Additionally, SC B1 decided to launch preparatory TFs to evaluate the need for future WGs on the following subjects: TF B1.62: Updating of TBs for EHVDC & UHVDC Cable Systems TB B1.63: Specifications for HVAC Dynamic Cables above 36kV TB B1.64: Evaluation of Armour Losses TB B1.65: Installation of Offshore Cable Systems

NEW WORKING BODIES of SC B1 The following WGs have been decided during SC Meeting and their ToRs prepared and approved by the TC Chairman during the second half of 2016: WG B1.58 Asset Management in MV Cable Systems (Detlef Wald/CH) WG B1.60 Maintenance of HV Cable Systems (Bart Mampaey/BE) WG B1.61 Installation of HV Cable Systems (Eugene Bergin/IR) Application of newer technologies for safer, cheaper, eco-friendly solutions Sustainability through practices for the extension of life Enlargement of scope to MV for power transmission lines

NEW WORKING BODIES of SC B1 Additionally, SC B1 decided to launch preparatory TFs to evaluate the need for future WGs on the following subjects: TF B1.62: Updating of TBs for EHVDC & UHVDC Cable Systems TB B1.63: Specifications for HVAC Dynamic Cables above 36kV TB B1.64: Evaluation of Armour Losses TB B1.65: Installation of Offshore Cable Systems Improved performances and practices for submarine cables Testing protocols for ultra-power transmission systems Attention to mechanical aspects associated to cables for RES

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