Hitachi Energy has introduced AxoniQ, a portfolio of solutions designed for multi-terminal direct current (MTDC) systems. The technology is intended to support evolving power systems as renewable energy capacity increases and grids become more interconnected. MTDC systems are used to help manage congestion and enable power flow between multiple terminals and across different energy markets. By linking several generation and demand points, they allow electricity to be routed to where it is required.
The AxoniQ portfolio combines power electronics and control technologies and includes the following components:
AxoniQ Protect: A protection system designed to interrupt DC faults in under three milliseconds at voltage levels of up to 525 kilovolts. It enables selective fault isolation by disconnecting only the affected section of a DC grid while allowing the rest of the system to remain in operation. This approach is intended to support continued operation of the wider network during faults and maintenance.
AxoniQ Connect: A modular DC switching station that allows additional terminals to be connected and divides the grid into protection zones. This creates smaller, more manageable subsystems and is intended to support maintenance and phased expansion.
AxoniQ Control: A control system designed to maintain voltage stability and balance power flows across the network. It supports grid reconfiguration during disturbances and is intended to enable coordinated operation and energy exchange between connected systems.
According to ENTSO-E’s Offshore Network Development Plans 2024 report, Europe is expected to enter a large-scale expansion phase of offshore renewable energy by 2040. This will require significant transmission build-out and early development of hybrid grid structures. The report indicates that MTDC-based grids could increase transmission capacity by up to nearly three times in a 2040 scenario.
