Assessment, Prevention and Mitigation of Safety Risk in Cable Systems

Introduction

Energy production from the Renewable Energy Sector (RES) and the interconnection between power grids is an area of rapid expansion all over the world, and electric energy demand increases in the largest metropolitan areas, particularly in the developing countries.  However, construction of new overhead transmission lines is becoming increasingly difficult due to social opposition and challenges to obtain approvals and permits – an example is the German Transmission System Operators (GTSO) project. 

As a result of these constraints, alternative solutions are required to increase transfer capacity between critical power grid sections, such as underground power cable interconnections and submarine cable systems.

In addition, the consequences of climate change with more frequent and intense storms, floods, heat waves, wildfires and other extreme events will consequently require the use of more underground cable networks which are inherently more resilient to climate‑related hazards. 

The increasing number of installations of insulated cable systems, both underground and submarine, driven by the needs mentioned above, increases the hazards and safety risks associated with the activities inherent to these installations.

Underground power cables undergo numerous quality control tests during manufacture such as type, pre-qualification, routine, sample, and commissioning tests (after laying or on-site tests). These tests are essential because the installation of accessories (terminations, clamps, and joints) introduces the human factor into the cable system, making commissioning and on‑site tests particularly important.

Utility technical specifications, often included in tender documentation, introduce diagnostic tests such as partial discharge (PD), time‑domain reflectometry (TDR), AC withstand, and dissipation factor measurements to evaluate the quality of the complete cable system. 

Handling procedures during manufacturing, transportation, installation, site acceptance testing, commissioning, operation, maintenance, repair, and eventual dismantling or decommissioning — require special focus to introduce generic methods and best practices to avoid or mitigate safety risks during every lifetime phase of both land and submarine cable systems. The assessment prevention and safety risk mitigation must be also considered during the planning, design and engineering phases of the project. 

Scope and Methodology

The scope of the brochure is broad yet focused. It covers safety risks in insulated cable systems—both underground and submarine—across all lifecycle phases, from planning and design to decommissioning. The primary concern is human safety, though environmental and ecosystem risks are acknowledged.

The objective is to provide guidance on how to reduce accidents and hazards for personnel and prevent damage to system components. Members of the Working Group contributed with reports of past events and real accidents by sharing experiences of the participating countries, enabling efficient and successful collection of information and lessons learned.

A previous Working Group of the Study Committee B1 (SC B1) evaluated all documents published by the SC (Technical Brochures, Electra Magazine, Special Reports,...