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Using a drone to analyze a 35-m-high surge tank at Taltson Hydro in Canada

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Using a drone to analyze a 35-m-high surge tank at Taltson Hydro in Canada

By Eloise McMinn Mitchell

Hydroelectric power is a highly scrutinized industry. The infrastructure is built with the best technology of the day. However, that technology is constantly developing. Over time, it is necessary to go back to the hydroelectric plant and update it and, where possible, upgrade the plant output.

The 18 MW Taltson Hydroelectric Facility is situated on the Taltson River, a 290-m-long waterway in the Northwest Territory of Canada. The Taltson plant was built in 1965 to supply electricity to the Pine Point Mine, a lead and zinc ore mine. Since 1986, when the mine was in the process of closing, the facility has provided primary power to communities in the South Slave region.

The turbine and generator as well as other key components have reached their end-of-life and must be replaced. The refurbishment of the Taltson turbine-generator unit will help ensure that electricity customers have access to renewable and reliable hydropower for the next 50 years. The hydroelectric power station has been taken offline for six months to enable this refurbishment. It will be overhauled, including installing a new turbine and a new generator and performing as-needed repair work.

Planning for future hydroelectric upgrades with drone mapping

Part of the expansive operations for the Taltson Hydro Plant’s refurbishment include the turbine being upgraded as well as the generator to increase the maximum capacity of the plant by 4 MW. To achieve this upgrade, all aspects of the water conveyance system must be inspected, with a particular focus on the penstock surge tank to understand its flow capacity and condition.

The penstock surge tank at Taltson Hydro reaches a height of 35 m and is a critical element because it is used as a damper during normal operation of the turbine.

Data collection to assess the condition of assets would also be critical to this process. A varied and expert team was assembled to gather data in and around the plant.

Mark Horton was part of the team from Dimension Consulting, brought in to digitize the hydro plant. He collaborated with Yannick Methot of GTA Hydro, the owner’s engineer. Together, they helped to assess and plan the upgrades to the plant.

Mark Nevison of Crux Trades is a rope access specialist who was contracted to help on high access points around the site. He is the team lead of the rope specialists helping with the refurbishment. Nevison had the idea to contact Osprey Integrity, drone service provider specialists, for some of the data collection. They were particularly interested in the surge tank, which reaches 35 m high. By using drones, they could help plan the best means of accessing any necessary work at height.

Including drones in inspection workflows

Osprey Integrity president Courtland Penk went to the site, which is incredibly remote — access is only possible via a small plane, rather than roads. The company needed to complete visual inspections as well as gather LiDAR imagery. For this reason, they felt that Flyability’s Elios 3 drone was the ideal solution for the project. It could safely collect data at height and inside the confined spaces of penstocks, tunnels, and the surge tank. They particularly wanted to look at the orifice of the surge tower and then move further inside the penstock with the drone.

With the flight planned and the right tool selected, all that remained was for Penk and his team to complete the flight.

The drone flight with the Elios 3 was incredibly quick, taking just 7 minutes to collect all of the necessary data in the 35-m-high surge tank. Afterwards, the Osprey Integrity team flew the drone further into the structure, analyzing the T-joint in the piping and tunnels, alongside visual imagery and LiDAR data collection.

Results of the Elios 3 surge tank inspection

The data from the flight with the Elios 3 drone was incredibly useful. Penk did initial processing with CloudCompare and Metashape before sharing it with a third-party contractor involved in the project. The extracted three-dimensional scan was then used to perform computational fluid dynamics analysis on the orifice and T-joint losses for the future operation of the surge tank.

Nevison and his team then used the drone inspection results to plan access for the rope engineers. This was vital, as they found that some structures in the tank they intended to use to secure the ropes had rusted through. There were also missing bolts and screws.

<<Taltson results>>

Caption: Results of analysis collected via the drone revealed some structures in the Taltson surge tank that were intended to secure the ropes were not safe.

In addition, they found that the T-joint had been built differently from the as-planned records, which was important information to confirm the maximum pressure capacity of the penstock with the new installations.

Impact of a drone inspection

The work done by Penk’s team in collaboration with Nevison and the rope access specialists highlighted how rope teams can work in partnership with drone inspections to enable safer and more efficient operations.

Penk and Osprey Integrity were able to provide more information than expected and helped streamline the refurbishment process. Soon enough, the Taltson Hydro Plant will be online with the new unit and ready to supply electricity to the local community, with steps being taken for a future upgrade to a 22 MW site from 18 MW.

Eloise McMinn Mitchell is content and communications manager with Flyability.