Editorial by Rob Stephen

Welcome to the 42^nd edition of CIGRE Science and Engineering (CSE), which brings together modelling and analysis with the practical challenges of grounding, equipment resilience and substation design. There are several areas of interest for different stakeholders:

1. For planners and system operators: connection, operation and planning considerations for large power electronics-interfaced loads.
2. For equipment specialists: transformer short-circuit withstand capability, winding fluid flow and end-of-life assessment.
3. For designers: grounding calculations, digital substations and probabilistic approaches to equipment-bay design.
4. For researchers and asset managers: AI-based predictive maintenance, real-time electromagnetic transient modelling and motor-drive fault behaviour.

The Joint Working Group paper, from C4/C2/C1, continues the discussion of large power electronics-interfaced loads. Part 2 moves into the connection process, operations and planning considerations: essential reading for those assessing how these loads will interact with the wider power system.

Transformer specialists have three complementary topics to explore.  A working group paper from A2.03 addresses guidelines for assessing short-circuit withstand capability. A separate paper examines deep learning for high-resolution three-dimensional pressure fields and fluid-flow distribution in OD/KD transformer windings.  A further joint working group paper from JWG A2/C3.70 turns to life cycle assessment at the end-of-life stage, extending the discussion from equipment performance to environmental assessment.

Two best papers from the GCC conference connect established engineering challenges with developing analytical approaches. One examines grounding-grid design calculations for FACTS and HVDC projects; the other considers a holistic approach to artificial intelligence in predictive maintenance and electrical equipment monitoring. Together, they offer readers a reason to explore both design practice and the changing tools available for asset management.

Grounding receives a second perspective in the paper on rodless systems, which examines analytical estimation of resistance for arrangements without vertical electrodes. Read alongside the FACTS and HVDC contribution, it invites closer attention to the assumptions behind grounding.

For readers concerned with dynamic behaviour, the paper on real-time substep electromagnetic transient (EMT) modelling focuses on multi-terminal HVDC systems. At equipment level, another contribution analyses a dual-star permanent-magnet synchronous motor drive under a switch short-circuit fault in motor operation. These papers approach system behaviour at different scales, linking the edition’s broader planning themes with detailed modelling and fault analysis.

Substation engineers will find two further perspectives: the challenges and technical requirements of digitisation in Colombia, and a mathematical approach to incorporating probabilistic design principles into outdoor substation equipment bays. They invite readers to consider how digital technology and explicit treatment of uncertainty might inform future designs.

As can be seen from the list of papers they a wide area of pertinent subjects critical to the power engineer.