RTE France and Amprion Commission Synchronized Cross-Border Grid Stability Control for High-Power Interties

French transmission operator RTE and German TSO Amprion have operationalized a synchronized cross-border wide-area monitoring and dynamic control scheme acro...

RTE France and Amprion Commission Synchronized Cross-Border Grid Stability Control for High-Power Interties

French transmission operator RTE and German TSO Amprion have operationalized a synchronized cross-border wide-area monitoring and dynamic control scheme across the Franco-German 400 kV border substations, coordinating phase-shifting transformers and fast-acting reactive power devices to maximize interconnection transfer capacity.

Unlocking Cross-Border Capacity Through Dynamic Phasor Coordination

Electricity flows across the central European synchronous grid frequently encounter loop flows and thermal bottlenecking during concurrent surges in German renewable feed-in and French nuclear exports. To manage these multidirectional stress patterns, RTE and Amprion deployed an automated Wide Area Monitoring System (WAMS).

The joint platform collects sub-second Phasor Measurement Unit (PMU) telemetry from border substations in Vigy, Muhlbach, and Ensdorf, computing dynamic thermal line ratings (DLR) and real-time angular stability margins across the 400 kV interconnections.

Automated Tap-Control of Phase-Shifting Transformers

Central to the system is the automated, synchronized adjustment of large 400 kV phase-shifting transformers (PSTs). Rather than relying on static seasonal dispatch angles, the new control architecture dynamically calculates optimal phase angle shifts to redirect circulating currents and prevent line overloads without tripping circuit breakers.

The PSTs feature rapid-switching vacuum on-load tap changers (OLTC) capable of executing automated multi-step tap changes under full load within seconds, backed by high-speed fiber-optic teleprotection interlinks conforming to IEC 61850-90-5.

Enhanced Resilience for the European Energy Union

By dynamically managing power flows and thermal headroom, the Franco-German intertie increases cross-border commercial trading capacity by up to 1,200 MW during peak market hours while significantly reducing redispatch costs paid by consumers.

The initiative serves as a model for neighboring European TSOs seeking to optimize existing cross-border transmission corridors through digital automation prior to constructing costly new physical lines.