TEPCO and Chubu Electric Energize 900 MW Higashi-Shimizu Back-to-Back VSC Frequency Converter Station

Overcoming Japan’s historical east-west electrical divide between 50 Hz and 60 Hz power systems, TEPCO Power Grid and Chubu Electric Power Grid have energize...

TEPCO and Chubu Electric Energize 900 MW Higashi-Shimizu Back-to-Back VSC Frequency Converter Station

Overcoming Japan’s historical east-west electrical divide between 50 Hz and 60 Hz power systems, TEPCO Power Grid and Chubu Electric Power Grid have energized the expanded 900 MW Higashi-Shimizu Frequency Converter (FC) Station, deploying ±100 kV Back-to-Back Modular Multilevel Converters.

Unifying Japan’s Dual-Frequency Transmission Network

Japan’s power grid has been fundamentally bisected since the 1890s, with eastern Japan (Tokyo) operating at 50 Hz and western Japan (Nagoya, Osaka) at 60 Hz. Following severe power sharing bottlenecks after the 2011 earthquake, utilities launched a national program to expand cross-frequency transfer capacity to 3,000 MW.

The newly commissioned Higashi-Shimizu Phase 2 expansion adds 900 MW of bidirectional transfer capacity using modern VSC-HVDC Back-to-Back valves interconnected via a shared direct-current busbar inside seismic-damped converter halls.

Advanced Active Harmonic Filtering and Black-Start Capability

The facility features four 500/275 kV converter transformers and high-speed IGBT semiconductor stacks that eliminate the need for massive AC harmonic filter yards required by older line-commutated converter (LCC) stations.

The back-to-back converters are programmed with black-start capability, allowing either the 50 Hz or 60 Hz grid to restore power to the adjacent system during major earthquake-induced blackout events.