Details:

Project: Lower Churchill HVDC Project

Service: LCC HVDC

Client: Nalcor

Country: Canada

Year: Our involvement began first back in 2007, and is currently on-going

Overview:

The Lower Churchill HVDC project is a 900 MW point-to-point LCC HVDC link connecting Labrador to Newfoundland Island in Canada. In the early stages of the project, it was originally planned to be a 3-terminal LCC HVDC link, and TGS performed a significant amount of studies for the 3-terminal option of the project. Later, it was decided it would be only a 2-terminal HVDC link. Currently, TGS is providing equipment-related services, as well as system support services, to Nalcor for this 2-terminal HVDC project. Additionally, TGS is a member of the technical integration committee, which is overseeing the successful integration of the Lower Churchill HVDC link, the nearby Maritime VSC link, three new synchronous condensers and a new 230 kV HVAC link on the Newfoundland Island.

TGS Study services:

In the early stages of the project, when it was originally planned to be a three-terminal HVDC link, TGS performed the following services:
  • AC Network Reduction— performed using PSS/E
  • Custom PSCAD HVDC Model & Reduced AC System Model Development
  • System Impact Studies — performed using PSS/E and PSCAD
    • Power flow
    • Short circuit
    • AC voltage stability
    • Transient stability
  • Electromagnetic Transient Studies — performed using PSCAD

TGS Project Execution services:

Currently, TGS is performing the following services:
  • Member of the technical integration committee, which oversees the successful integration of the Lower Churchill HVDC link, the nearby Maritime VSC link, three new synchronous condensers and a new 230 kV HVAC link on the Newfoundland Island.
  • Review of HVDC manufacturer design reports
  • Witnessing of testing

TGS Power Quality services:

  • Harmonic measurements — on site
  • TGS performed background harmonic measurements for the potential converter locations

Challenges:

This project is was challenging in that due to its importance to the island and the unique geography and transmission line route, it required a 2pu overload (per pole), a 400km electrode and a cable switching scheme to allow uninterrupted transmission in the event of a contingency.