New technical requirements for Large Demand Facilities in Finland

The ongoing energy transition is introducing large-scale demand facilities into the Finnish power system, with capacities ranging from several hundred megawatts to gigawatt scale. These facilities primarily include data centers, green steel production, power-to-gas installations, and electric boilers. The operational behavior of such high-capacity loads has a significant impact on the stability and performance of the power system.

As the transmission system operator (TSO) with system responsibility, Fingrid is accountable for ensuring the technical functionality and security of Finland’s power system. In response to the evolving system landscape, Fingrid aims to publish an updated grid code for demand facilities by 2026.

To support this objective, Fingrid has conducted comprehensive studies to assess system needs related to frequency stability, voltage stability, and secure interconnection operations. These studies utilized a range of analytical tools, including a dynamic model of the Finnish power system.

Grid measurements and simulations indicate that voltage dips caused by typical grid faults propagate across wide areas, particularly within the 400 kV network. This phenomenon is attributed to the reduced number of synchronous generators and the increased grid strength, which lowers impedance between nodes. Projections for 2030 suggest a worsening trend, underscoring the importance of ensuring that large demand facilities can ride through grid faults. Failure to do so could jeopardize system frequency, especially since generation units are generally equipped with fault ride-through capabilities.

Two critical technical requirements for maintaining frequency and voltage stability are Low Voltage Ride Through (LVRT) and Post-Fault Active Power Recovery (PFAPR). Additionally, large demand facilities often include substantial reactive power compensation systems for power factor correction, which must be carefully managed during transients to prevent overvoltages in the transmission network.

Another key consideration is the potential for control interactions, particularly given the prevalence of converter-connected loads. Special attention must be paid to load types such as AI training clusters, which may excite inter-area oscillation modes.

Recognizing the diversity of load types and their primary processes, Fingrid acknowledges that a uniform set of technical requirements may not be techno-economically feasible. Therefore, requirements may be tailored based on the specific characteristics of each load type.

This paper outlines the key findings from the system studies, presents the main technical requirements for demand facilities, and briefly describes the compliance process.