Our expertise in HVDC and FACTS technology

Our expertise in hvdc & FACTS technology

Our services

The large-scale development of renewable energy and public demand to avoid the construction of new overhead lines has led to an increase in new HVDC links using underground DC cables. The increasing penetration of power electronics-based devices in the grid also has a significant impact on grid performance and reliability. It requires improvements in control and protection systems and understanding of dynamic behaviour. RTE International provides services in the field of power systems with a focus on HVDC and FACTS. We offer comprehensive services to meet the needs of the evolving power industry. Its team of experts from a wide range of backgrounds, specialising in power electronics and power systems, addresses a wide variety of technical challenges in the field of power transmission.

Testing of HVDC/FACTS control and protection systems.

Testing the implementation of new C&P functions several years after commissioning requires specialised tools and skills.

  • Testing of C&P software updates
  • Accelerating the return to service of equipment
  • Analysis of events recorded on site

Dynamic analysis of HVDC/FACTS performance

Detailed power system studies with HVDC/FACTS.

  • Development of converter station models for EMT simulations
  • EMT simulation with complex AC networks
  • Real-time simulation with physical C&P cells
  • Identification of potential interactions

Integration of renewable energy

Specific analysis for the connection of wind farms to transmission networks.

  • Harmonic amplification analysis
  • Sizing of harmonic filters
  • EMT simulation in the time domain for transformer and cable supply

Real-time simulation with HVDC/FACTS control replicas

The largest multi-vendor HVDC/FACTS real-time simulation laboratory in Europe

  • Study interaction phenomena related to HVDC and FACTS devices
  • Study and test multi-vendor and multi-power systems
  • Training engineers and supporting maintenance activities
  • Testing of control and protection software updates
  • Network studies and improving offline models

Principle of real-time simulation with physical control replicas

  • Over 10 real-time simulators with associated I/O boards
  • 2000 m² of technical premises to host HVDC and FACTS control replicas
  • Dedicated rooms to host third party project replicas

Electrical systems studies

Analysis of complex systems

  • HVDC/FACTS systems in transmission networks
  • Integration of long AC cables or a reactive compensation device
  • Integration of wind farms

Different types of analysis

  • Simulation of electromagnetic transients (EMT)
  • Harmonic analysis
  • Transient stability simulation
  • Harmonic analysis and impedance locus calculation

Example of harmonic analysis for the connection of an offshore wind farm

The TSO usually provides harmonic impedances at the point of common coupling for wind farms. RTE determined the harmonic impedances based on the minimum and maximum short circuit of the system. The final harmonic study reflects the results of several thousand simulations corresponding to different grid topologies and load conditions.

The overall results are summarised as surfaces in the RX plane (R: real part of the impedance and X: imaginary part of the impedance).

HVDC/FACTS project management

Supporting projects from planning to maintenance

  • Technical specification of HVDC/FACTS equipment
  • Improving specifications and optimising system performance
  • Evaluation of bids for HVDC applications
  • Analysis of design reports
  • Factory control and protection – witness testing
  • Preparation of test and commissioning procedures for HVDC/FACTS control and protection systems
  • Supervision of on-site testing
  • Engineering training and maintenance support activities


Wide range of topics for HVDC projects and EMT simulation

  • Basics of HVDC-LCC and HVDC-VSC
  • HVDC control and protection
  • HVDC modelling and studies
  • Maintenance of HVDC systems and integration into AC networks
  • HVDC VSC project management
  • EMT modelling and simulations – basic concepts
  • EMT modelling and simulations – advanced concepts for transmission networks

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