Project 36.008 – HVDC Cable and HVAC Submarine Cable Systems
Objective
Significant trends are developing in applications of high-voltage direct current (HVDC) cable systems for power-grid integration and interconnections. Increasingly, HVDC cable systems and high-voltage alternating current (HVAC) submarine cable systems are being used for power transmission from remote renewable-energy generation to power grids. The line distances of HVDC cable circuits are steadily increasing for both land and submarine applications. All these occurrences are being enabled by advances in HVDC and HVAC submarine cable and converter technologies. More cable manufacturers are offering HVDC cables and HVAC submarine cables or adding manufacturing capacity in anticipation of the growing demands. Research is needed to:
- Understand needs, trends, and technologies for HVDC system integration with existing power grids
- Develop tools for effective designs and implementations
- Understand failure mechanisms and demonstrate inspection, diagnostic, monitoring, and fault-location methods
- Provide guidance, develop strategies, and share practices for effective operation, inspection, and maintenance
Engineers, designers, and managers of underground transmission can use the tools and methods developed in this project to effectively apply, operate, and maintain HVDC transmission and HVAC submarine cable technologies. Utility engineers may use an improved understanding of the HVDC and HVAC submarine cable systems to achieve effective and economical system designs and determine system ratings. Maintenance departments can deploy new fault location methods and tools to locate faults more efficiently, especially for long-distance HVDC and HVAC submarine cables.
Approach
This project investigates and develops methods and tools for effective applications of HVDC cable and HVAC submarine cable technologies for system integration and interconnection. The project:
Analyzes and evaluates design tools for utility engineers to prepare feasibility studies and verify proposals and implementations
Assesses cable-insulation materials and aging characteristics to optimize designs and extend the life of HVDC cable and HVAC submarine cable systems
Evaluates operational practices in application of HVDC cable and HVAC submarine cable technologies, based on technical and economic benefits and increased power-transfer capability requirements
Measures condition-assessment, maintenance, inspection, and fault location technologies to meet operation and maintenance requirements
Research Value
This research produces new understanding, methods, and tools that can assist engineers and designers to apply, operate, and maintain HVDC and HVAC submarine transmission cable systems as well as extend asset life and prevent unexpected outages. For example:
- The use of reference books, design tools, and other investigative results may lead to more effective designs and applications for power grid integration, interconnection, and transmission.
- Effective inspection and monitoring of assets could lead to increased asset utilization, rapid maintenance intervention, improved reliability, and reduced repair costs.
- Better understanding of failure mechanisms and prevention procedures may result in longer asset life, reduced customer outages, and lower operating costs.
Anticipated Deliverables
| Deliverable | Description | Date |
|---|---|---|
| EPRI High-Voltage, Direct Current (HVDC) Transmission Reference Book (The Olive Book) – 2027 Edition (Technical Report) | The EPRI Olive Book is a state-of-the-art guidebook and comprehensive source of technical information for designing, building, operating, and extending the life of HVDC transmission systems. The project team continuously updates the Olive Book. | December 2027 |
| Underground Transmission Workstation—DC Ampacity (Software) | This task aims to enhance the stand-alone Underground Transmission Workstation (UTW) DC ampacity calculation software tool for HVDC transmission cables. The calculation procedures are based on previous EPRI studies. | December 2027 |
| Guide for High-Voltage Direct Current (HVDC) Transmission Cable Ratings – 2027 Update (Technical Report) | This report provides calculation procedures for continuous ratings of buried land or submarine HVDC transmission cables. | December 2027 |
| Off-Line Fault Location Systems for Transmission AC and DC Cables – 2027 Update (Technical Report) | Off-line fault location is critical for determining the location of a cable fault. This task provides results of a study in applying and demonstrating developed fault location technology for long distance HVDC cables and HVAC submarine cables. | December 2027 |
| Guide on HVAC and HVDC Array and Export Power Cables for Offshore Wind Farms – 2027 Edition (Technical Report) | This task is a multi-year effort addressing technical challenges in exporting a large amount of energy from offshore wind collectors to land-based grid connections. Both HVDC and HVAC technologies are investigated, including best practices and the state of technology from design to operation and maintenance. | December 2027 |