Medium Voltage Soft Starters for Centrifugal Chillers

ITER Fusion Research Facility – France

 The ITER Fusion Research Facility in Cadarache, France, is one of the most ambitious scientific infrastructure projects ever undertaken. Developed through an international collaboration of 34 nations, ITER aims to demonstrate the feasibility of nuclear fusion as a large-scale, carbon-free energy source.

Because of the scale and complexity of the project, the facility requires highly reliable electrical and mechanical infrastructure. One critical element is the central cooling infrastructure, where centrifugal chillers maintain stable operating temperatures for multiple subsystems throughout the ITER complex.

Reliable operation of these chillers depends on the controlled starting of large compressor motors. Therefore, medium voltage soft starters were specified to ensure smooth motor acceleration while maintaining electrical stability across the facility’s medium voltage power distribution network.

Application: Centrifugal Chiller Motor Control

The centrifugal chillers installed at the ITER site are driven by 800 kW medium voltage induction motors. Motors of this size require a carefully controlled starting process to prevent excessive inrush current and reduce mechanical stress on compressor components.

Consequently, the motor starting solution needed to provide:

• Controlled starting of large medium voltage motors
• Reduced inrush current and voltage disturbances on the MV network
• Protection selectivity with the facility electrical grid
• Integration with plant protection and monitoring systems
• Reliable operation within a mission-critical infrastructure environment
• Long-term performance with minimal maintenance requirements

In a facility such as ITER, where multiple high-power systems operate simultaneously, maintaining electrical stability during motor startup is essential for overall plant reliability.

Solcons’ Solution

To meet these requirements, Solcon supplied eight HRVS-DN medium voltage soft starter systems, each designed for 800 kW centrifugal chiller motors operating within the ITER facility.

The HRVS-DN platform provides controlled motor acceleration by gradually increasing the voltage supplied to the motor. As a result, starting current is limited while the compressor system reaches operating speed smoothly and efficiently.

In addition, each system integrates Solcon’s MPS3000 motor protection relay, which provides advanced protection, monitoring, and communication capabilities while maintaining protection selectivity with the facility electrical grid.

Each unit was delivered as a complete cabinet system, engineered to meet the project’s electrical integration and installation requirements.

Key System Capabilities

• Controlled starting and stopping of medium voltage motors
• MPS3000 motor protection relay with coordinated protection selectivity
• Winding and bearing temperature monitoring and protection
• Adjustable current limit and acceleration ramp
• Profibus communication connected to the MPS3000, enabling monitoring of current, voltage, and operational events
• Custom cabinet configuration for site installation
• Integration with facility monitoring and control systems

All units were factory tested prior to delivery and supplied between 2016 and 2017 as part of the ITER construction and commissioning schedule.

Operational Performance

Since commissioning, the HRVS-DN soft starters have supported the facility’s cooling infrastructure by providing reliable starting of the centrifugal chiller motors.

Key project outcomes include:

• 8 medium voltage soft starters installed
• Reliable operation since commissioning
• 7 units remain in original delivered configuration
• One cabinet refurbished following environmental exposure during construction
• Continued operation within design specifications

Overall, the installation demonstrates how medium voltage soft starters combined with advanced motor protection and monitoring can support large compressor and chiller applications in complex infrastructure environments.

Medium Voltage Soft Starters for Critical Infrastructure

Large research facilities, industrial plants, and energy infrastructure projects depend on reliable motor control systems for pumps, compressors, and chillers.

In these applications, medium voltage soft starters provide a proven method for:

• Reducing electrical stress on medium voltage power networks
• Protecting mechanical equipment during motor startup
• Supporting stable operation of critical infrastructure systems

The HRVS-DN installation at the ITER project site demonstrates how properly engineered medium voltage motor starting and protection solutions deliver reliable performance in demanding technical environments.