Labrador-Island Link

The Labrador-Island Transmission Link (LIL) is a high-voltage direct current (HVDC) transmission system connecting the Muskrat Falls Hydroelectric Generating Facility in Labrador to the island of Newfoundland. It is part of the Lower Churchill Project, designed to transmit power from Labrador to the island and beyond.

Technical Specifications

The LIL is configured as a ±320 kV, 900 MW bipolar transmission system using Line Commutated Converter (LCC) HVDC technology. The total length of the transmission line is approximately 1,100 km, making it one of the longest transmission lines of its kind in North America.

Key Components

Converter Stations

The system includes two converter stations: the Muskrat Falls Converter Station in Labrador and the Soldiers Pond Converter Station in Newfoundland. The Muskrat Falls station converts alternating current (AC) power from the generating facility into direct current (DC) power for long-distance transmission. The Soldiers Pond station converts the DC power back into AC power for distribution through the island's electricity grid.

Transmission Lines

The LIL consists of two main sections of overhead transmission lines. The first section spans 400 km from Muskrat Falls to the Strait of Belle Isle. The second section covers 700 km from Shoal Cove on the Newfoundland side of the Strait to Soldiers Pond on the Avalon Peninsula. The overhead transmission lines use steel towers ranging from 35 to 45 meters in height. Each tower supports two main conductor wires for power transmission and a smaller wire for lightning protection.

Strait of Belle Isle Crossing

The marine cable crossing of the Strait of Belle Isle consists of three ±350 kV submarine cables, each approximately 30 km long. The cables enter the Strait through horizontally directionally drilled (HDD) holes from both shores and are laid on the sea floor with appropriate protection.

Electrodes

The system includes two shoreline pond electrodes: the L'Anse au Diable electrode in Labrador and the Dowden's Point electrode in Conception Bay, Newfoundland. These electrodes, connected to their respective converter stations by small overhead transmission lines, serve as high-capacity grounding systems for the HVDC link.

Technical Advantages

HVDC technology was chosen for this project due to its effectiveness in transmitting large amounts of power over long distances and underwater. The LIL's design allows for voltage and frequency control when injecting power into the island's electrical system at Soldiers Pond.

Associated Infrastructure

The project includes various supporting infrastructure elements. These include a 1 km access road from the Trans-Canada Highway to the Soldiers Pond converter station, upgrades to the existing transmission system on the island, including the installation of synchronous condensers at Soldiers Pond for reactive power support, and modifications to the existing underfrequency load shedding scheme and implementation of special protection schemes.

Operational Aspects

The LIL's actual operating levels fluctuate throughout the day based on load requirements. It is integrated with other generation assets in Newfoundland and Labrador's power system, typically allowing for more than 90% of electricity to be generated from renewable sources. The commissioning of the LIL has significantly reduced reliance on the Holyrood Thermal Generating Station, particularly during summer months when Holyrood can be taken offline, allowing for 100% renewable energy generation.

Labrador Island link enables Newfoundland and Labrador's energy infrastructure to harness and transmit clean, renewable energy from Labrador to the island and potentially to export markets.