HVDC Transmission (LCC and VSC)

HVDC projects are on the rise around the world, in particular, VSC HVDC projects are gaining significant popularity. At TGS, we perform all steady state, short circuit, transient stability, SSR and EMT studies that are needed to study an HVDC project. We also develop custom HVDC models for transient stability and EMT applications.

Full scale of technology studies using EMT simulations

“To understand the technology and what can be expected from the manufacturer”

  • Verification of the performance of different converter technologies
  • Controller performance at different AC system strengths
  • Special controller and protection requirements
  • DC fault clearance mechanisms
  • Arrester requirements
  • DC resonance studies
  • AC/DC harmonic analysis
  • AC and DC filter design and analysis

System impact studies

“To identify the feasibility of an HVDC interconnection, along with the AC system upgrades and special requirements to be added to the DC controls”

  • Power flow analysis to identify and mitigate thermal loading and steady state voltage issues
  • Voltage stability analysis
  • Short circuit analysis to identify minimum and maximum short circuit levels at the HVDC terminals, to calculate the
  • Effective Short Circuit Ratio (ESCR), and to determine the breaker requirements
  • Transient stability analysis to determine dynamic performance of the interconnected AC and HVDC systems, and to determine the need for any special DC controls such as frequency, power oscillation damping and run-up or run-back schemes

Frequency Response Studies

“To provide information for AC/DC filter and controller design”

  • In-house developed special harmonics impedance scan program
  • Handling of frequency dependency of lines, transformers, generators loads and existing filters/shunts
  • Determine if DC line resonances are possible and, if so, propose mitigation

AC/DC Coupling Studies

“To determine the impact of an HVDC link on neighbouring AC circuits and vice versa”

  • Steady state and transient impact on parallel AC/DC transmission lines and other infrastructures (pipelines, telecommunication systems, etc.)
  • Impact of coupling on HVDC converter operation
  • Investigation of coupling suppression techniques