Vattenfall Pioneers Ethernet-Based Relay Protection System to Boost Swedish Power Grid Reliability

Vattenfall Eldistribution has initiated testing of a novel communication solution for relay protection within Sweden's regional power grid, aiming to improve fault detection speed and grid reliability. This innovative system, which began operation just before Christmas 2025, enables information transfer between protection systems via Ethernet, marking a world-first in its real-world application, according to Per Kriewitz, a Vattenfall power system specialist.

The technology primarily operates on lines with voltages between 70 and 130 kilovolts, employing longitudinal differential protection (LDS) to detect short circuits within milliseconds by comparing electrical measurements at different points along a power line. With around 400 lines currently utilizing LDS, the new Ethernet-based communication replaces older specialized equipment, allowing for more standardized protection systems and facilitating faster upgrades.

A significant advancement in the system is the use of ground-based atomic clocks for precise time synchronization, replacing previously GPS-based methods, which enhances the accuracy of measurements critical for fault identification. The positive initial results have encouraged Vattenfall to plan further implementation of this technology across more lines in 2026, as part of ongoing efforts to modernize the regional grid's protection and monitoring capabilities.